Internet Engineering Task Force M. Pei
Internet-Draft Symantec
Intended status: Informational N. Cook
Expires: January 9, 2017 Intercede
M. Yoo
Solacia
A. Atyeo
Intercede
H. Tschofenig
ARM Ltd.
July 8, 2016

The Open Trust Protocol (OTrP)
draft-pei-opentrustprotocol-01.txt

Abstract

This document specifies the Open Trust Protocol (OTrP), a protocol to install, update, and delete applications and to manage security configuration in a Trusted Execution Environment (TEE).

TEEs are used in environments where security services should be isolated from a regular operating system (often called rich OS). This form of compartmentlization grants a smaller codebase access to security sensitive services and restricts communication from the rich OS to those security services via mediated access.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at http://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on January 9, 2017.

Copyright Notice

Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved.

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.


Table of Contents

1. Introduction

The Trusted Execution Environment (TEE) concept has been designed and used to increase security by separating regular operating systems, also referred as Rich Execution Environment (REE), from security-sensitive applications. In an TEE ecosystem, a Trust Service Manager (TSM) is used to authorize manage keys and the Trusted Applications (TA) that run in a device. Different device vendors may use different TEE implementations. Different application providers may use different TSM providers. There arises a need of an open interoperable protocol that allows trustworthy TSM to manage security domains and contents running in different Trusted Execution Environment (TEE) of various devices.

The Open Trust Protocol (OTrP) defines a protocol between a TSM and a TEE and relies on IETF-defined end-to-end security mechanisms, namely JSON Web Encryption (JWE), JSON Web Signature (JWS), and JSON Web Key (JWK).

This specification assumes that a device that utilizes this specification is equipped with a TEE and is pre-provisioned with a device-unique public/private key pair, which is securely stored. This key pair is referred as the 'root of trust'. A Service Provider (SP) uses such a device to run Trusted Applications (TA).

A security domain is defined as the TEE representation of a service provider and is a logical space that contains the service provider's trusted applications. Each security domain requires the management operations of trusted applications (TAs) in the form of installation, update and deletion.

The protocol builds on the following properties of the system:

  1. The SP needs to determine security-relevant information of a device before provisioning information to a TEE. Examples include the verification of the root of trust, the type of firmware installed, and the type of TEE included in a device.
  2. A TEE in a device needs to determine whether a SP or the TSM is authorized to manage applications in the TEE.
  3. Secure Boot must be able to ensure a TEE is genuine.

This specification defines message payloads exchanged between devices and a TSM but does not mandate a specific transport.

2. Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].

3. Terminology

3.1. Definitions

The definitions provided below are defined as used in this document. The same terms may be defined differently in other documents.

Client Application:
An application running on a rich OS, such as an Android, Windows, or iOS application, provided by a SP.

Device:
A physical piece of hardware that hosts symmetric key cryptographic modules

OTrP Agent:
An application running in the rich OS allowing communication with the TSM and the TEE.

Rich Application:
Alternative name of "Client Application". In this document we may use these two terms interchangably.

Rich Execution Environment (REE)
An environment that is provided and governed by a rich OS, potentially in conjunction with other supporting operating systems and hypervisors; it is outside of the TEE. This environment and applications running on it are considered un-trusted.

Secure Boot Module (SBM):
A firmware in a device that delivers secure boot functionality. It is also referred as Trusted Firmware (TFW) in this document.

Service Provider (SP):
An entity that wishes to supply Trusted Applications to remote devices. A Service Provider requires the help of a TSM in order to provision the Trusted Applications to the devices.

Trust Anchor:
A root certificate that a module trusts. It is usually embedded in one validating module, and used to validate the trust of a remote entity's certificate.

Trusted Application (TA):
Application that runs in TEE.

Trusted Execution Environment (TEE):
An execution environment that runs alongside but isolated from an REE. A TEE has security capabilities and meets certain security-related requirements: It protects TEE assets from general software attacks, defines rigid safeguards as to data and functions that a program can access, and resists a set of defined threats. There are multiple technologies that can be used to implement a TEE, and the level of security achieved varies accordingly.

3.2. Abbreviations

CA
Certificate Authority
OTrP
Open Trust Protocol
REE
Rich Execution Environment
SD
Security Domain
SP
Service Provider
SBM
Secure Boot Module
TA
Trusted Application
TEE
Trusted Execution Environment
TFW
Trusted Firmware
TSM
Trusted Service Manager

4. OTrP Entities and Trust Model

4.1. System Components

There are the following main components in this OTrP system.

TSM:
The TSM is responsible for originating and coordinating lifecycle management activity on a particular TEE.
A Trust Service Manager (TSM) is at the core to the protocol that manages device trust check on behalf of service providers for the ecosystem scalability. In addition to its device trust management for a service provider, the TSM provides Security Domain management and TA management in a device, in particularly, over-the-air update to keep Trusted Applications up to date and clean up when a version should be removed.

In the context of this specification, the term Trusted Application Manager (TAM) and TSM are synonymous.
Certificate Authority (CA):
Mutual trust between a device and a TSM as well as a Service Provider is based on certificates. A device embeds a list of root certificates, called Trust Anchors, from trusted Certificate Authorities that a TSM will be validated against. A TSM will remotely attest a device by checking whether a device comes with a certificate from a trusted CA.
TEE:
The TEE resides in the device chip security zone and is responsible for protecting applications from attack, enabling the application to perform secure operations
REE:
The REE, usually called device OS such as Android OS in a phone device, is responsible for enabling off device communications to be established between the TEE and TSM. OTrP does not require the device OS to be secure.
OTrP Agent:
An application in the REE that can relay messages between a Client Application and TEE.
Secure Boot:
Secure boot (for the purposes of OTrP) must enable authenticity checking of TEEs by the TSM.

The OTrP establishes appropriate trust anchors to enable TEE and TSMs to communicate in a trusted way when performing lifecycle management transactions. The main trust relationships between the components are the following.

  1. TSM must be able to ensure a TEE is genuine
  2. TEE must be able to ensure a TSM is genuine
  3. Secure Boot must be able to ensure a TEE is genuine

4.2. Trusted Anchors in TEE

The TEE in each device comes with a trust store that contains a whitelist of TSM's root CA certificates, which are called Trust Anchors. A TSM will be trusted to manage Security Domains and TAs in a device only if its certificate is chained to one of the root CA certificates in this trust store.

Such a list is typically embedded in TEE of a device, and the list update is enabled and handled by device OEM provider.

4.3. Trusted Anchors in TSM

The Trust Anchor set in a TSM consists of a list of Certificate Authority certificates that signs various device TEE certificates. A TSM decides what TEE and TFW it will trust.

4.4. Keys and Cerificate Types

OTrP Protocol leverages the following list of trust anchors and identities in generating signed and encrypted command messages that are exchanged between a device with TEE and a TSM. With these security artifacts, OTrP Messages are able to deliver end-to-end security without relying on any transport security.

Key and Certificate Types
Key Entity Name Location Issuer Trust Implication Cardinality
1. TFW keypair and Certificate Device secure storage OEM CA A white list of FW root CA trusted by TSMs 1 per device
2. TEE keypair and Certificate Device TEE TEE CA under a root CA A white list of TEE root CA trusted by TSMs 1 per device
3. TSM keypair and Certificate TSM provider TSM CA under a root CA A white list of TSM root CA embedded in TEE 1 or multiple can be used by a TSM
4. SP keypair and Certificate SP SP signer CA TSM manages SP. TA trust is delegated to TSM. TEE trusts TSM to ensure that a TA is trustworthy. 1 or multiple can be used by a TSM

1. TFW keypair and Certificate:
A key pair and certificate for evidence of secure boot and trustworthy firmware in a device.
Location:
Device secure storage
Supported Key Type:
RSA and ECC
Issuer:
OEM CA
Trust Implication:
A white list of FW root CA trusted by TSMs
Cardinality:
One per device

2. TEE keypair and Certificate:
It is used for device attestation to remote TSM and SP.
This key pair is burned into the device at device manufacturer. The key pair and its certificate are valid for the expected lifetime of the device.
Location:
Device TEE
Supported Key Type:
RSA and ECC
Issuer:
TEE CA that chains to a root CA
Trust Implication:
A white list of TEE root CA trusted by TSMs
Cardinality:
One per device

3. TSM keypair and Certificate:
A TSM provider acquires a certificate from a CA that a TEE trusts.
Location:
TSM provider
Supported Key Type:
RSA and ECC.
Supported Key Size:
RSA 2048-bit, ECC P-256 and P-384.
Issuer:
TSM CA that chains to a root CA
Trust Implication:
A white list of TSM root CA embedded in TEE
Cardinality:
One or multiple can be used by a TSM

4. SP keypair and Certificate:
A SP uses its own key pair and certificate to sign a TA.
Location:
SP
Supported Key Type:
RSA and ECC
Supported Key Size:
RSA 2048-bit, ECC P-256 and P-384
Issuer:
SP signer CA that chains to a root CA
Trust Implication:
TSM manages SP. TA trust is delegated to TSM. TEE trusts TSM to ensure that a TA is trustworthy.
Cardinality:
One or multiple can be used by a SP

5. Protocol Scope and Entity Relations

This document specifies the minimally required interoperable artifacts to establish mutual trust between a TEE and TSM. The protocol provides specifications for the following three entities:

  1. Key and certificate types required for device firmware, TEE, TA, SP, and TSM
  2. Data message formats that should be exchanged between a TEE in a device and a TSM
  3. An OTrP Agent application in the REE that can relay messages between a Client Application and TEE

Figure 1: Protocol Scope and Entity Relationship

PKI    CA    --CA                                   CA--
        |    |                                         |
        |    |                                         |
        |    |                                         |
Device  |    |   ----OTrP Agent --- Rich App ---       |
SW      |    |   |                             |       |
        |    |   |                             |       |
        |    |   |                             |       |
OTrP    |    -- TEE                           TSM-------
        |
        |
       FW 
          

Figure 2: OTrP System Diagram


              ---OTrP Message Protocol--
              |                        |
              |                        |
 --------------------           ---------------   ----------
 |  REE   |  TEE    |           |    TSM      |   |  SP    |
 |  ---   |  ---    |           |    ---      |   |  --    |
 |        |         |           |             |   |        |
 | Client | SD (TAs)|           |   SD / TA   |   |  TA    |
 |  Apps  |         |           |     Mgmt    |   |        |
 |   |    |         |           |             |   |        |
 |   |    |         |           |             |   |        |
 | OTrP   | Trusted |           |  Trusted    |   |        |
 | Agent  |  CAs    |           | FW, TEE CAs |   |        |
 |        |         |           |             |   |        |
 |        |TEE Key/ |           |  TSM Key/   |   |SP Key/ |
 |        |  Cert   |           |    Cert     |   | Cert   |
 |        | FW Key/ |           |             |   |        |
 |        |  Cert   |           |             |   |        |
 ------------------             ---------------   ----------
              |                        |              |
              |                        |              |
              -----------------------------------------
                                |
                                |
                          --------------
                          |    CA      |
                          --------------                                                 
          

In the previous diagram, different Certificate Authorities can be used respectively for different types of certificates. OTrP Messages are always signed, where the signer keys is the message creator's key pair such as a FW key pair, TEE key pair or TSM key pair.

The main OTrP Protocol component is the set of standard JSON messages created by TSM to deliver device SD and TA management commands to a device, and device attestation and response messages created by TEE to respond to TSM OTrP Messages.

The communication method of OTrP Messages between a TSM and TEE in a device is left to TSM providers for maximal interoperability. A TSM can work with its SP and Client Applications how it gets OTrP Messages from a TSM. When a Client Application has had an OTrP Message from its TSM, it is imperative to have an interoperable interface to communicate with various TEE types. This is the OTrP Agent interface that serves this purpose. The OTrP Agent doesn't need to know the actual content of OTrP Messages except for the TEE routing information.

5.1. A Sample Device Setup Flow

TBD

5.2. Derived Keys in the Protocol

The protocol generates the following two key pairs in run time to assist message communication and anonymous verification between TSM and TEE.

1. TEE Anonymous Key (TEE AIK): one derived key pair per TEE in a device

The purpose of the key pair is to sign data by a TEE without using its TEE device key for anonymous attestation to a Client Application. This key is generated in the first GetDeviceState query. The public key of the key pair is returned to the caller Client Application for future TEE returned data validation.

2. TEE SP AIK: one derived key per SP in a device

The purpose of this key pair is for a TSM to encrypt TA binary data when it sends a TA to a device for installation. This key is generated in the first SD creation for a SP. It is deleted when all SDs are removed for a SP in a device.

With the presence of a TEE SP AIK, it isn't necessary to have a shared SP independent TEE AIK. For the initial release, this specification will not use TEE AIK.

5.3. Security Domain Hierarchy and Ownership

The primary job of a TSM is to help a SP to manage its trusted applications. A TA is typically installed in a SD. A SD is commonly created for a SP.

When a SP delegates its SD and TA management to a TSM, a SD is created on behalf of a TSM in a TEE and the owner of the SD is assigned to the TSM. A SD may be associated with a SP but the TSM has full privilege to manage the SD for the SP.

Each SD for a SP is associated with only one TSM. When a SP changes TSM, a new SP SD must be created to associate with the new TSM. TEE will maintain a registry of TSM ID and SP SD ID mapping.

From a SD ownership perspective SD tree is flat and there is only one level. A SD is associated with its owner. It is up to TEE's implementation how it maintains SD binding information for TSM and different SPs under the same TSM.

It is an important decision in this protocol specification that a TEE doesn't need to know whether a TSM is authorized to manage SD for a SP. This authorization is implicitly triggered by a SP Client Application, which instructs what TSM it wants to use. A SD is always associated with a TSM in addition to its SP ID. A rogue TSM isn't able to do anything on an unauthorized SP's SD managed by another TSM.

Since a TSM may support multiple SPs, sharing the same SD name for different SP creates a dependency in deleting a SD. A SD can be deleted only after all TAs associated with this SD is deleted. A SP cannot delete a Security Domain on its own with a TSM if a TSM decides to introduce such sharing. There are cases where multiple virtual SPs belong to the same organization, and a TSM chooses to use the same SD name for those SPs. This is totally up to the TSM implementation and out of scope of this specification.

5.4. SD Owner Identification and TSM Certificate Requirements

There is a need of cryptographically binding proof about the owner of a SD in device. When a SD is created on behalf of a TSM, a future request from the TSM must present itself as a way that the TEE can verify it is the true owner. The certificate itself cannot reliably used as the owner because TSM may change its certificate.

To this end, each TSM will be associated with a trusted identifier defined as an attribute in the TSM certificate. This field is kept the same when the TSM renew its certificates. A TSM CA is responsible to vet the requested TSM attribute value.

This identifier value must not collide among different TSM providers, and one TSM shouldn't be able to claim the identifier used by another TSM provider.

The certificate extension name to carry the identifier can initially use SubjectAltName:registeredID. A dedicated new extension name may be registered later.

One common choice of the identifier value is the TSM's service URL. A CA can verify the domain ownership of the URL with the TSM in the certificate enrollment process.

TEE can assign this certificate attribute value as the TSM owner ID for the SDs that are created for the TSM.

An alternative way to represent a SD ownership by a TSM is to have a unique secret key upon SD creation such that only the creator TSM is able to produce a Proof-of-Possession (POP) data with the secret.

5.5. Service Provider Container

A sample Security Domain hierarchy for the TEE is shown below.

[[TBD diagram]]

The OTrP assumes that a SP managed by TSM1 cannot be managed by TSM2. Explicit permission grant should happen. SP can authorize TSM.

6. OTrP Agent

OTrP Agent is an Rich Application or SDK that facilitates communication between a TSM and TEE. It also provides interfaces for TSM SDK or Client Applications to query and trigger TA installation that the application needs to use.

This interface for Client Applications may be commonly an Android service call. A Client Application interacts with a TSM, and turns around to pass messages received from TSM to OTrP Agent.

In all cases, a Client Application needs to be able to identify an OTrP Agent that it can use.

6.1. Role of OTrP Agent

OTrP Agent is responsible to communicate with TEE. It takes request messages from an application. The input data is mostly from a TSM that an application communicates. An application may also directly call OTrP Agent for some TA query functions.

OTrP Agent may internally process a request from TSM. At least, it needs to know where to route a message, e.g. TEE instance. It doesn't need to process or verify message content.

OTrP Agent returns TEE / TFW generated response messages to the caller. OTrP Agent isn't expected to handle any network connection with an application or TSM.

OTrP Agent only needs to return an OTrP Agent error message if the TEE is not reachable for some reason. Other errors are represented as response messages returned from the TEE which will then be passed to the TSM.

6.2. OTrP Agent and Global Platform TEE Client API

A Client Application may rely on Global Platform (GP) TEE API for TA communication. OTrP may use the GP TEE Client API but it is internal to OTrP implementation that converts given messages from TSM. More details can be found at [GPTEE].

6.3. OTrP Agent Implementation Consideration

A Provider should consider methods of distribution, scope and concurrency on device and runtime options when implementing an OTrP Agent. Several non-exhaustive options are discussed below. Providers are encouraged to take advantage of the latest communication and platform capabilities to offer the best user experience.

6.3.1. OTrP Agent Distribution

OTrP Agent installation is commonly carried out at OEM time. A user can dynamically download and install an OTrP Agent on-demand.

It is important to ensure a legitimate OTrP Agent is installed and used. If an OTrP Agent is compromised it may send rogue messages to TSM and TEE and introduce additional risks.

6.3.2. Number of OTrP Agent

We anticipate only one shared OTrP Agent instance in a device. The device's TEE vendor will most probably supply one OTrP Agent. Potentially we expect some open source.

With one shared OTrP Agent, the OTrP Agent provider is responsible to allow multiple TSMs and TEE providers to achieve interoperability. With a standard OTrP Agent interface, TSM can implement its own SDK for its SP Client Applications to work with this OTrP Agent.

Multiple independent OTrP Agent providers can be used as long as they have standard interface to a Client Application or TSM SDK. Only one OTrP Agent is expected in a device.

OTrP Protocol MUST specify a standard way for applications to lookup the active OTrP Agent instance in a device.

TSM providers are generally expected to provide SDK for SP applications to interact with OTrP Agent for the TSM and TEE interaction.

6.3.3. OTrP Android Service Option

OTrP Agent can be a bound service in Android with a service registration ID that a Client Application can use. This option allows a Client Application not to depend on any OTrP Agent SDK or provider.

An OTrP Agent is responsible to detect and work with more than one TEE if a device has more than one. In this version, there is only one active TEE such that an OTrP Agent only needs to handle the active TEE.

6.4. OTrP Agent API for Client Applications

The client application shall be responsible for relaying messages between the OTrP agent and the TSM.

OTrP Agent APIs are defined below. An OTrP Agent in the form of an Android bound service can take this to be the functionality it provides via service call. The OTrP Agent implements this interface.

If a failure is occured during calling API, an error message described in "Common Errors" section (see Section 7.6) will be returned.

interface IOTrPAgentService {
  String processMessage(String tsmInMsg) throws OTrPAgentException;
  String getTAInformation(String spid, String taid) 
     throws OTrPAgentException;
}

public class OTrPAgentException extends Throwable {
  private int errCode;
}
           

6.4.1. API processMessage

String processMessage(String tsmInMsg) throws OTrPAgentException;
           

Description

Input

Output

6.4.2. API getTAInformation

String getTAInformation(String spid, String taid) 
   throws OTrPAgentException;

Description

Input

{
  "TAInformationTBS": {
    "taid": "<TA Identifier from the input>",
    "tsmid": "<TSM ID for the Security Domain where this TA 
              resides>",
    "spid": "<The service provider identifier of this TA>",
    "signercert": "<The BASE64 encoded certificate data of the TA
                   binary application's signer certificate>",
    "signercacerts": [ // the full list of CA certificate chain 
                       // including  the root CA
    "cacert": "<The BASE64 encoded CA certificate data of the TA 
                   binary application's signer certificate>"
    ],
    "tsmcert": "<The BASE64 encoded certificate data of the TSM that
                 manages this TA.>",
    "tsmcacerts": [ // the full list of CA certificate chain 
                    // including the root CA
    "cacert":"<The BASE64 encoded CA certificate data of the TSM
                  that manages this TA>"
    ]
  }
}

{
  "TAInformation": {
      "payload": "<BASE64URL encoding of the TAInformationTBS 
                  JSON above>",
      "protected": "<BASE64URL encoded signing algorithm>",
      "header": {
          "signer": {"<JWK definition of the TEE SP AIK public 
                      key>"}
      },
      "signature": "<signature contents signed by TEE SP AIK private
                    key BASE64URL encoded>"
  }
}

Output

6.5. Sample End-to-End Client Application Flow

6.5.1. Case 1: A new Client App uses a TA

  1. During the Client App installation time, the Client App calls TSM to initialize device preparation
    1. The Client Application knows it wants to use a TA1 but the application doesn'tknow whether TA1 has been installed or not. It can use GP TEE Client API to check the existence of TA1 first. If it doesn't exist, it will contact TSM to initiate the TA1 installation. Note that TA1 could have been installed that is triggered by other Client Applications of the same service provider in the same device.
    2. The Client Application sends TSM the TA list that it depends on. The TSM will query a device for the Security Domains and TAs that have been installed, and instructs the device to install any dependent TAs that have not been installed.
    3. In general, TSM has the latest information of TA list and their status in a device because all operations are instructed by TSM. TSM has such visibility because all Security Domain deletion and TA deletion are managed by TSM; the TSM could have stored the state when a TA is installed, updated and deleted. There is also the possibility that an update command is carried out inside TEE but a response is never received in TSM. There is also possibility that some manual local reset is done in a device that the TSM isn't aware of the changes.

  2. TSM generates message: GetDeviceStateRequest
  3. The Client Application passes the JSON message GetDeviceStateRequest to OTrP Agent API processMessage. The communication between a Client Application and OTrP Agent is up to the implementation of OTrP Agent.
  4. OTrP Agent routes the message to the active TEE. Multiple TEE case: it is up to OTrP Agent to figure this out. This specification limits the support to only one active TEE, which is the typical case today.
  5. The target active TEE processes the received OTrP message, returns a JSON message GetDeviceStateResponse
  6. The OTrP Agent passes the GetDeviceStateResponse to the Client App
  7. The Client Application sends GetDeviceStateResponse to TSM
  8. TSM processes GetDeviceStateResponse
    1. Extract TEEspaik for the SP, signs TEEspaik with TSM signer key
    2. Examine SD list and TA list

  9. TSM continues to carry out other actions basing on the need. The next call could be instructing the device to install a dependent TA.
    1. Assume a dependent TA isn't in the device yet, the TSM may do the following:
      • Create a SD to install the TA by sending a message CreateSDRequest. The message is sent back to the Client Application, and then OTrP Agent and TEE to process.
      • Install a TA with a message InstallTARequest.

    2. If a Client Application depends on multiple TAs, the Client Application should expect multiple round trips of the TA installation message exchanges.

  10. At the last TSM and TEE operation, TSM returns the signed TEE SP AIK public key to the application
  11. The Client Application shall store the TEEspaik for future loaded TA trust check purpose.
  12. If the TSM finds that this is a fresh device that does not have any SD for the SP yet, then the TSM may move on to create a SD for the SP next. The TSM may move on to create a SD for the SP next.
  13. During Client Application installation, the application checks whether required Trusted Applications are already installed, which may have been provided by TEE. If needed, it will contact its TSM service to determine whether the device is ready or install TA list that this application needs.

6.5.2. Case 2: A previously installed Client Application calls a TA

  1. The Client Application checks the device readiness: (a) whether it has a TEE; (b) whether it has TA that it depends. It may happen that TSM has removed TA this application depends on.
  2. The Client App calls OTrP Agent method "GetTAInformation"
  3. OTrP Agent queries the TEE to get TA information. If the given TA doesn't exist, an error is returned
  4. The Client App parses the TAInformation message.
  5. If the TA doesn't exist, the Client App calls its TSM to install the TA. If the TA exists, the Client App proceeds to call the TA.

7. OTrP Messages

The main OTrP Protocol component is the set of standard JSON messages created by TSM to deliver device SD and TA management commands to a device, and device attestation and response messages created by TEE to respond to TSM OTrP Messages.

An OTrP Message is designed to provide end-to-end security. It is always signed by its creator. In addition, an OTrP Message is typically encrypted such that only the targeted device TEE or TSM provider is able to decrypt and view the actual content.

7.1. Message Format

OTrP Messages use JSON format for JSON's simple readability and moderate data size in comparison with alternative TLV and XML formats.

JSON Message security has developed JSON Web Signing and JSON Web Encryption standard in the IETF Workgroup JOSE, see JWS [RFC7515] and JWE [RFC7516]. The OTrP Messages in this protocol will leverage the basic JWS and JWE to handle JSON signing and encryption.

7.2. Message Naming Convention

For each TSM command "xyz"", OTrP Protocol use the following naming convention to represent its raw message content and complete request and response messages:

Purpose Message Name Example
Request to be signed xyzTBSRequest CreateSDTBSRequest
Request message xyzRequest CreateSDRequest
Response to be signed xyzTBSResponse CreateSDTBSResponse
Response message xyzResponse CreateSDResponse

7.3. Request and Response Message Template

An OTrP Request message uses the following format:

  {
    "<name>TBSRequest": {
      <request message content>
    }
  }
           

A corresponding OTrP Response message will be as follows.

  {
    "<name>TBSResponse": {
      <response message content>
    }
  }
           

7.4. Signed Request and Response Message Structure

A signed request message will generally include only one signature, and uses the flattened JWS JSON Serialization Syntax, see Section 7.2.2 in RFC7515 [RFC7515] .

A general JWS object looks like the following.

{
  "payload": "<payload contents>",
  "protected":"<integrity-protected header contents>",
  "header": {
    <non-integrity-protected header contents>,
  },
  "signature":"<signature contents>"
}
           

OTrP signed messages only requires the signing algorithm as the mandate header in the property "protected". The "non-integrity-protected header contents" is optional.

OTrP signed message will be given an explicit Request or Response property name. In other words, a signed Request or Response uses the following template.

A general JWS object looks like the following.

{
  "<name>[Request | Response]": {
    <JWS Message of <name>TBS[Request | Response]
  }
}
           

With the standard JWS message format, a signed OTrP Message looks like the following.

{
  "<name>[Request | Response]": {
    "payload": "<payload contents of <name>TBS[Request | Response]>",
    "protected":"<integrity-protected header contents>",
    "header":  <non-integrity-protected header contents>,
    "signature":"<signature contents>"
  }
}
           

The top element " <name>[Signed][Request | Response]" cannot be fully trusted to match the content because it doesn't participate the signature generation. However, a recipient can always match it with the value associated with the property "payload". It purely serves to provide a quick reference for reading and method invocation.

Furthermore, most properties in an unsigned OTrP messages are encrypted to provide end-to-end confidentiality. The only OTrP message that isn't encrypted is the initial device query message that asks for the device state information.

Thus a typical OTrP Message consists of an encrypted and then signed JSON message. Some transaction data such as transaction ID and TEE information may need to be exposed to OTrP Agent for routing purpose. Such information is excluded from JSON encryption. The device's signer certificate itself is encrypted. The overall final message is a standard signed JSON message.

As required by JSW/JWE, those JWE and JWS related elements will be BASE64URL encoded. Other binary data elements specific to the OTrP specification are BASE64 encoded. This specification will identify elements that should be BASE64 and those elements that are to be BASE64URL encoded.

7.4.1. Identifying signing and Encryption keys for JWS/JWE messaging

JWS and JWE messaging allow various options for identifying the signing and encryption keys, for example, it allows optional elements including "x5c", "x5t" and "kid" in the header to cover various possibilities.

In order to protect privacy, it is important that the device's certificate is released only to a trusted TSM, and that it is encrypted. The TSM will need to know the device certificate, but untrusted parties must not be able to get the device certificate. All OTrP messaging conversations between a TSM and device begin with GetDeviceStateRequest / GetDeviceStateResponse. These messages have elements built into them to exchange signing certificates, described in the "Detailed Message Specification" section. Any subsequent messages in the conversation that follow on from this are implicitly using the same certificates for signing/encryption, and as a result the certificates or references may be ommitted in those subsequent messages.

In other words, the signing key identifier in the use of JWS and JWE here may be absent in the subsequent messages after the initial GetDeviceState query.

This has implication on the TEE and TSM implementation: they have to cache the signer certificates for the subsequent message signature validation in the session. It may be easier for a TSM service to cache transaction session information but not so for a TEE in a device. A TSM should check a device's capability to decide whether it should include its TSM signer certificate and OCSP data in each subsequent request message. The device's caching capability is reported reported in GetDeviceStateResponse signerreq parameter.

7.5. JSON Signing and Encryption Algorithms

The OTrP JSON signing algorithm shall use SHA256 or a stronger hash method with respective key type. JSON Web Algorithm RS256 or ES256 [RFC7518] SHALL be used for RSA with SHA256 and ECDSA with SHA256. If RSA with SHA256 is used, the JSON web algorithm representation is as follows.

The (BASE64URL encoded) "protected" header property in a signed message looks like the following:

If ECSDA with P-256 curve and SHA256 are used for signing, the JSON signing algorithm representation is as follows.

The value for the "protected" field will be the following.

Thus a common OTrP signed message with ES256 looks like the following.

  {
    "payload": "<payload contents>",
     "protected": "eyJhbGciOiJFUzI1NiJ9",
    "signature":"<signature contents>"
  }
           

The OTrP JSON message encryption algorithm should use one of the supported algorithms defined in the later chapter of this document. JSON encryption uses a symmetric key as its "Content Encryption Key (CEK)". This CEK is encrypted or wrapped by a recipient's key. OTrP recipient typically has an asymmetric key pair. Therefore CEK will be encrypted by the recipient's public key.

Symmetric encryption shall use the following algorithm.

This algorithm represents encryption with AES 128 in CBC mode with HMAC SHA 256 for integrity. The value of the property "protected" in a JWE message will be

An encrypted JSON message looks like the following.

  {
    "protected": "eyJlbmMiOiJBMTI4Q0JDLUhTMjU2In0",
     "recipients": [
        {
            "header": {
                "alg": "<RSA1_5 etc.>"
            },
            "encrypted_key": "<encrypted value of CEK>"
        } 
    ],
    "iv": "<BASE64URL encoded IV data>",
    "ciphertext": "<Encrypted data over the JSON plaintext 
                   (BASE64URL)>",
    "tag": "<JWE authentication tag (BASE64URL)>"
  }
           

OTrP doesn't use JWE AAD (Additional Authenticated Data) because each message is always signed after the message is encrypted.

7.5.1. Supported JSON Signing Algorithms

The following JSON signature algorithm are mandatory support in TEE and TSM:

ES256 is optional to support.

7.5.2. Support JSON Encryption Algorithms

The following JSON authenticated encryption algorithm is mandatory support in TEE and TSM.

A256CBC-HS512 is optional to support.

7.5.3. Supported JSON Key Management Algorithms

The following JSON key management algorithm is mandatory support in TEE and TSM.

ECDH-ES+A128KW and ECDH-ES+A256KW are optional to support.

7.6. Common Errors

An OTrP Response message typically needs to report operation status and error causes if an operation fails. The following JSON message elements should be used across all OTrP Messages.

"status": "pass | fail"

 "reason": {
     "error-code": "<error code if there is any>",
     "error-message": "<error message>"
  }


"ver": "<version string>"
           

7.7. OTrP Message List

The following table lists the OTrP commands and therefore corresponding Request and Response messages defined in this specification. Additional messages may be added in the future when new task messages are needed.

GetDeviceState -

A TSM queries a device's current state with a message GetDeviceStateRequest. A device TEE will report its version, its FW version, and list of all SD and TA in the device that is managed by the requesting TSM. TSM may determine whether the device is trustworthy and decide to carry out additional commands according to the response from this query.
CreateSD -

A TSM instructs a device TEE to create a SD for a SP. The recipient TEE will check whether the requesting TSM is trustworthy.
UpdateSD -

A TSM instructs a device TEE to update an existing SD. A typical update need comes from SP certificate change, TSM certificate change and so on. The recipient TEE will verify whether the TSM is trustworthy and owns the SD.
DeleteSD -

A TSM instructs a device TEE to delete an existing SD. A TEE conditionally deletes TAs loaded in the SD according to a request parameter. A SD cannot be deleted until all TAs in this SD are deleted. If this is the last SD for a SP, TEE can also delete TEE SP AIK key for this SP.
InstallTA -

A TSM instructs a device to install a TA into a SD for a SP. TEE in a device will check whether the TSM and TA are trustworthy.
UpdateTA -

A TSM instructs a device to update a TA into a SD for a SP. The change may commonly be bug fix for a previously installed TA.
DeleteTA -

A TSM instructs a device to delete a TA. TEE in a device will check whether the TSM and TA are trustworthy.

7.8. OTrP Request Message Routing Rules

For each command that a TSM wants to send to a device, the TSM generates a request message. This is typically triggered by a Client Application that uses the TSM. The Client Application initiates contact with the TSM and receives TSM OTrP Request messages according to the TSM's implementation. The Client Application forwards the OTrP message to an OTrP Agent in the device, which in turn sends the message to the active TEE in the device.

The current version of specification assumes that each device has only one active TEE, and OTrP Agent is responsible to connect to the active TEE. This is the case today with devices in the market.

Upon TEE responding with a request, the OTrP Agent gets OTrP response messages back to the Client Application that sends the request. In case the target TEE fails to respond the request, the OTrP Agent will be responsible to generate an error message to reply the Client Application. The Client Application forwards any data it received to its TSM.

7.8.1. SP Anonymous Attestation Key (SP AIK)

When the first new Security Domain is created in TEE for a SP, a new key pair is generated and associated with this SP. This key pair is used for future device attestation to the service provider instead of using device's TEE key pair.

8. Detailed Messages Specification

For each message in the following sections all JSON elements are mandatory if it isn't explicitly indicated as optional.

8.1. GetDeviceState

This is the first command that a TSM will query a device. This command is triggered when a SP's Client Application contacts its TSM to check whether the underlying device is ready for TA operations.

This command queries a device's current TEE state. A device TEE will report its version, its FW version, and list of all SD and TA in the device that is managed by the requesting TSM. TSM may determine whether the device is trustworthy and decide to carry out additional commands according to the response from this query.

The request message of this command is signed by TSM. The response message from TEE is encrypted. A random message encryption key (MK) is generated by TEE, and this encrypted key is encrypted by the receiving TSM public key such that only the TSM who sent the request is able to decrypt and view the response message.

8.1.1. GetDeviceStateRequest message

{
   "GetDeviceStateTBSRequest": {
      "ver": "1.0",
      "rid": "<Unique request ID>",
      "tid": "<transaction ID>",
      "ocspdat": "<OCSP stapling data of TSM certificate>",
      "icaocspdat": "<OCSP stapling data for TSM CA certificates>",
      "supportedsigalgs": "<comma separated signing algorithms>"
    }
}
           

The request message consists of the following data elements:

ver -
version of the message format
rid -
a unique request ID generated by the TSM
tid -
a unique transaction ID to trace request and response. This can be from a prior transaction's tid field, and can be used in the subsequent message exchanges in this TSM session. The combination of rid and tid should be made unique.
ocspdat -
OCSP stapling data for the TSM certificate. The TSM provides OCSP data such that a recipient TEE can validate the validity of the TSM certificate without making its own external OCSP service call. This is a mandate field.
icaocspdat -
OCSP stapling data for the intermediate CA certificates of the TSM certificate up to the root. A TEE side can cache CA OCSP data such that this value isn't needed in each call.
supportedsigalgs -
an optional property to list the signing algorithms that TSM is able to support. A recipient TEE should choose algorithm in this list to sign its response message if this property is present in a request.

The final request message is JSON signed message of the above raw JSON data with TSM's certificate.

{
  "GetDeviceStateRequest": {
    "payload":"<BASE64URL encoding of the GetDeviceStateTBSRequest
               JSON above>",
    "protected": "<BASE64URL encoded signing algorithm>",
    "header": {
        "x5c": "<BASE64 encoded TSM certificate chain up to the 
                root CA certificate>"
    },
    "signature":"<signature contents signed by TSM private key>"
  }
}
          

The signing algorithm should use SHA256 with respective key type. The mandatory algorithm support is the RSA signing algorithm. The signer header "x5c" is used to include the TSM signer certificate up to the root CA certificate.

8.1.2. Request processing requirements at a TEE

Upon receiving a request message GetDeviceStateRequest at a TEE, the TEE must validate a request:

  1. Validate JSON message signing
  2. Validate that the request TSM certificate is chained to a trusted CA that the TEE embeds as its trust anchor.
    • Cache the CA OCSP stapling data and certificate revocation check status for other subsequent requests.
    • A TEE can use its own clock time for the OCSP stapling data validation.
  3. Validate JSON message signing
  4. Collect Firmware signed data
    • This is a capability in ARM architecture that allows a TEE to query Firmware to get FW signed data.
  5. Collect SD information for the SD owned by this TSM

8.1.3. Firmware signed data

Firmware isn't expected to process or produce JSON data. It is expected to just sign some raw bytes of data.

The data to be signed by TFW key needs be some unique random data each time. The (UTF-8 encoded) "tid" value from the GetDeviceStateTBSRequest shall be signed by the firmware. TSM isn't expected to parse TFW data except the signature validation and signer trust path validation.

It is possible that a TEE can get some valid TFW signed data from another device. This is part of the TEE trust assumption where TSM will trust the TFW data supplied by the TEE. The TFW trust is more concerned by TEE than a TSM where a TEE needs to ensure that the underlying device firmware is trustworthy.

          
  TfwData: {
       "tbs": "<TFW to be signed data, BASE64 encoded>",
       "cert": "<BASE64 encoded TFW certificate>",
       "sigalg": "Signing method",
       "sig": "<Tfw signed data,  BASE64 encoded>"
  }
           

It is expected that FW use a standard signature methods for maximal interoperability with TSM providers. The mandatory support list of signing algorithm is RSA with SHA256.

The JSON object above is constructed by TEE with data returned from FW. It isn't a standard JSON signed object. The signer information and data to be signed must be specially processed by TSM according to definition given here. The data to be signed is the raw data.

8.1.3.1. Supported Firmware Signature Methods

TSM providers shall support the following signature methods. A firmware provider can choose one of the methods in signature generation.

The value of "sigalg" in the TfwData JSON message should use one of the following:

8.1.4. Post Conditions

Upon successful request validation, the TEE information is collected. There is no change in the TEE in the device.

The response message shall be encrypted where the encryption key shall be a symmetric key that is wrapped by TSM's public key. The JSON Content Encryption Key (CEK) is used for this purpose.

8.1.5. GetDeviceStateResponse message

The message has the following structure.

  { 
    "GetDeviceTEEStateTBSResponse": {
        "ver": "1.0",
        "status": "pass | fail",
        "rid": "<the request ID from the request message>",
        "tid": "<the transaction ID from the request message>",
        "signerreq": "true | false about whether TSM needs to send 
                      signer data again in subsequent messages",
        "edsi": "<Encrypted JSON dsi information>"
    }
 }
           

where

signerreq -
true if the TSM should send its signer certificate and OCSP data again in the subsequent messages. The value may be "false" if the TEE caches the TSM's signer certificate and OCSP status.
rid -
the request ID from the request message
tid -
the tid from the request message
edsi -
the main data element whose value is JSON encrypted message over the following Device State Information (DSI).

The Device State Information (DSI) message consists of the following.

{
    "dsi": {
        "tfwdata": {
            "tbs": "<TFW to be signed data is the tid>"
            "cert": "<BASE64 encoded TFW certificate>",
            "sigalg": "Signing method",  
            "sig": "<Tfw signed data,  BASE64 encoded>"
        },
        "tee": {
            "name": "<TEE name>",
            "ver": "<TEE version>",
            "cert": "<BASE64 encoded TEE cert>",
            "cacert": "<JSON array value of CA certificates up to 
                        the root CA>",
            "sdlist": {
                "cnt": "<Number of SD owned by this TSM>",
                "sd": [
                    {
                        "name": "<SD name>",
                        "spid": "<SP owner ID of this SD>",
                        "talist": [
                          {
                             "taid": "<TA application identifier>",
                             "taname": "<TA application friendly 
                                       name>" // optional
                          }
                        ]
                    }
                ] 
            },
            "teeaiklist": [
                {
                    "spaik": "<SP AIK public key, BASE64 encoded>",
                    "spaiktype": "<RSA | ECC>",
                    "spid": "<sp id>"
                }
            ]
        }
    }
} 
           

The encrypted JSON message looks like the following.

{
    "protected": "<BASE64URL encoding of encryption algorithm header 
                   JSON data>",
    "recipients": [
        {
            "header": {
                "alg": "RSA1_5"
            },
            "encrypted_key": "<encrypted value of CEK>"
        } 
    ],
    "iv": "<BASE64URL encoded IV data>",
    "ciphertext": "<Encrypted data over the JSON object of dsi 
                    (BASE64URL)>",
    "tag": "<JWE authentication tag (BASE64URL)>"
}
           

Assume we encrypt plaintext with AES 128 in CBC mode with HMAC SHA 256 for integrity, the encryption algorithm header is:

The value of the property "protected" in the above JWE message will be

In other words, the above message looks like the following:

{
    "protected": "eyJlbmMiOiJBMTI4Q0JDLUhTMjU2In0",
     "recipients": [
        {
            "header": {
                "alg": "RSA1_5"
            },
            "encrypted_key": "<encrypted value of CEK>"
        } 
    ],
    "iv": "<BASE64URL encoded IV data>",
    "ciphertext": "<Encrypted data over the JSON object of dsi 
                    (BASE64URL)>",
    "tag": "<JWE authentication tag (BASE64URL)>"
}
           

The full response message looks like the following:

{
  "GetDeviceTEEStateTBSResponse": {
    "ver": "1.0",
    "status": "pass | fail",
    "rid": "<the request ID from the request message>",
    "tid": "<the transaction ID from the request message>",
    "signerreq": "true | false", 
    "edsi": {
      "protected": "<BASE64URL encoding of encryption algorithm 
                     header JSON data>",
      "recipients": [
        {
          "header": {
            "alg": "RSA1_5"
          },
          "encrypted_key": "<encrypted value of CEK>"
        }
      ],
      "iv": "<BASE64URL encoded IV data>",
      "ciphertext": "<Encrypted data over the JSON object of dsi
                      (BASE64URL)>",
      "tag": "<JWE authentication tag (BASE64URL)>"
    }
  }
}
           

The CEK will be encrypted by the TSM public key in the device. The TEE signed message has the following structure.

{
  "GetDeviceTEEStateResponse": {
    "payload": "<BASE64URL encoding of the JSON message 
                 GetDeviceTEEStateTBSResponse>",
    "protected": "<BASE64URL encoding of signing algorithm>",
    "signature": "<BASE64URL encoding of the signature value>"
  }
}
           

The signing algorithm shall use SHA256 with respective key type, see Section Section 7.5.1.

The final response message GetDeviceStateResponse consists of array of TEE response. A typical device will have only one active TEE. An OTrP Agent is responsible to collect TEE response for all active TEEs in the future.

{
    "GetDeviceStateResponse": [ // JSON array 
       {"GetDeviceTEEStateResponse": ...},
       ...
       {"GetDeviceTEEStateResponse": ...}
    ]    
}
           

8.1.6. Error Conditions

An error may occur if a request isn't valid or the TEE runs into some error. The list of possible error conditions is the following.

ERR_REQUEST_INVALID
The TEE meets the following conditions with a request message: (1) The request from a TSM has an invalid message structure; mandatory information is absent in the message. undefined member or structure is included. (2) TEE fails to verify signature of the message or fails to decrypt its contents. (3) etc.
ERR_UNSUPPORTED_MSG_VERSION
TEE receives the version of message that TEE can't deal with.
ERR_UNSUPPORTED_CRYPTO_ALG
TEE receives a request message encoded with cryptographic algorithms that TEE doesn't support.
ERR_TFW_NOT_TRUSTED
TEE may consider the underlying device firmware be not trustworthy.
ERR_TSM_NOT_TRUSTED
TEE needs to make sure whether the TSM is trustworthy by checking the validity of TSM certificate and OCSP stapling data and so on. If TEE finds TSM is not reliable, it may return this error code.
ERR_TEE_FAIL
TEE fails to respond to a TSM request. The OTrP Agent will construct an error message in responding the TSM's request. And also if TEE fails to process a request because of its internal error, it will return this error code.

The response message will look like the following if the TEE signing can work to sign the error response message.

          
  {
      "GetDeviceTEEStateTBSResponse": {
          "ver": "1.0",
          "status": "fail",
          "rid": "<the request ID from the request message>",
          "tid": "<the transaction ID from the request message>",
          "reason": {"error-code":"<error code>"}
          "supportedsigalgs": "<signature algorithms TEE supports>"
      }
  }
           

where

supportedsigalgs -
an optional property to list the JWS signing algorithms that the active TEE supports. When a TSM sends a signed message that the TEE isn't able to validate, it can include signature algorithms that it is able to consume in this status report. A TSM can generate a new request message to retry the management task with a TEE supported signing algorithm.

If TEE isn't able to sign an error message, a general error message should be returned.

8.1.7. TSM Processing Requirements

Upon receiving a message of the type GetDeviceStateResponse at a TSM, the TSM should validate the following.

8.2. Security Domain Management

8.2.1. CreateSD

This command is typically preceded with GetDeviceState command that has acquired the device information of the target device by the TSM. TSM sends such a command to instruct a TEE to create a new Security Domain for a SP.

A TSM sends an OTrP Request message CreateSDRequest to a device TEE to create a Security Domain for a SP. Such a request is signed by TSM where the TSM signer may or may not be the same as the SP's TA signer certificate. The resulting SD is associated with two identifiers for future management:

A Trusted Application that is signed by a matching SP signer certificate for a SD is eligible to be installed into that SD. The TA installation into a SD by a subsequent InstallTARequest message may be instructed from TSM or a Client Application.

8.2.1.1. CreateSDRequest Message

The request message for CreateSD has the following JSON format.

{
   "CreateSDTBSRequest": {
     "ver": "1.0",
     "rid": "<unique request ID>",
     "tid": "<transaction ID>", // this may be from prior message
     "tee": "<TEE routing name from the DSI for the SD's target>",
     "nextdsi": "true | false",
     "dsihash": "<hash of DSI returned in the prior query>",
     "content": ENCRYPTED { // this piece of JSON data will be 
                             // encrypted
           "spid": "<SP ID value>",
        "sdname": "<SD name for the domain to be created>",        
        "spcert": "<BASE64 encoded SP certificate>",
        "tsmid": "<An identifiable attribute of the TSM 
                   certificate>",
        "did": "<SHA256 hash of the TEE cert>"
     }
   }
}
             

In the message,

rid -
A unique value to identify this request
tid -
A unique value to identify this transaction. It can have the same value for the tid in the preceding GetDeviceStateRequest.
tee -
TEE ID returned from the previous response GetDeviceStateResponse
nextdsi -
Indicates whether the up to date Device State Information (DSI) should be returned in the response to this request.
dsihash -
The BASE64 encoded SHA256 hash value of the DSI data returned in the prior TSM operation with this target TEE. This value is always included such that a receiving TEE can check whether the device state has changed since its last query. It helps enforce SD update order in the right sequence without accidently overwrite an update that was done simultaneously.
content -
The "content" is a JSON encrypted message that includes actual input for the SD creation. The encryption key is TSMmk that is encrypted by the target TEE's public key. The entire message is signed by the TSM private key TSMpriv. A separate TSMmk isn't used in the latest specification because JSON encryption will use a content encryption key for exactly the same purpose.
spid -
A unique id assigned by the TSM for its SP. It should be unique within a TSM namespace.
sdname -
a name unique to the SP. TSM should ensure it is unique for each SP.
spcert -
The SP's TA signer certificate is included in the request. This certificate will be stored by the device TEE and uses it to check against TA installation. Only if a TA is signed by a matching spcert associated with a SD the TA will be installed into the SD.
tsmid -
SD owner claim by TSM - A SD owned by a TSM will be associated with a trusted identifier defined as an attribute in the signer TSM certificate. TEE will be responsible to assign this ID to the SD. The TSM certificate attribute for this attribute TSMID must be vetted by the TSM signer issuing CA. With this trusted identifier, SD query at TEE can be fast upon TSM signer verification.
did -
The SHA256 hash of the binary encoded device TEE certificate. The encryption key CEK will be encrypted the recipient TEE's public key. This hash value in the "did" property allows the recipient TEE to check whether it is the expected target to receive such a request. If this isn't given, an OTrP message for device 2 could be sent to device 1. It is optional for TEE to check because the successful decryption of the request message with this device's TEE private key already proves it is the target. This explicit hash value makes the protocol not dependent on message encryption method in future.

Following is the OTrP message template, the full request is signed message over the CreateSDTBSRequest as follows.

{
    "CreateSDRequest": {
        "payload":"<CreateSDTBSRequest JSON above>",
        "protected":"<integrity-protected header contents>",
        "header":  <non-integrity-protected header contents>,
        "signature":"<signature contents signed by TSM private key>"
    }
}
             

TSM signer certificate is included in the "header" property.

8.2.1.2. Request processing requirements at a TEE

Upon receiving a request message CreateSDRequest at a TEE, the TEE must validate a request:

  1. Validate the JSON request message
    • Validate JSON message signing
    • Validate that the request TSM certificate is chained to a trusted CA that the TEE embeds as its trust anchor
    • Compare dsihash with its current state to make sure nothing has changed since this request was sent.
    • Decrypt to get the plaintext of the content: (a) spid, (b) sd name, (c) did
    • Check that a SPID is supplied
    • spcert check: check it is a valid certificate (signature and format verification only)
    • Check "did" is the SHA256 hash of its TEEcert BER raw binary data
    • Check whether the requested SD already exists for the SP
    • Check TSMID in the request matches TSM certificate's TSM ID attribute

  2. Create action
    • Create a SD for the SP with the given name
    • Assign the TSMID from the TSMCert to this SD
    • Assign the SPID and SPCert to this SD
    • Check whether a TEE SP AIK keypair already exists for the given SP ID
    • Create TEE SP AIK keypair if it doesn't exist for the given SP ID
    • Generate new DSI data if the request asks for updated DSI

  3. Construct CreateSDResponse message
    • Create raw content
      • Operation status
      • "did" or full signer certificate information,
      • TEE SP AIK public key if DSI isn't going to be included
      • Updated DSI data if requested if the request asks for it

    • The response message is encrypted with the same JWE CEK of the request without recreating a new content encryption key.
    • The encrypted message is signed with TEEpriv. The signer information ("did" or TEEcert) is encrypted.

  4. Deliver response message. (a) OTrP Agent returns this to the app; (b) The app passes this back to TSM
  5. TSM process. (a) TSM processes the response message; (b) TSM can look up signer certificate from device ID "did".

If a request is illegitimate or signature doesn't pass, a "status" property in the response will indicate the error code and cause.

8.2.1.3. CreateSDResponse Message

The response message for a CreateSDRequest contains the following content.

{  
  "CreateSDTBSResponse": {
    "ver": "1.0",
    "status": "<operation result>",
    "rid": "<the request ID received>",
    "tid": "<the transaction ID received>",
    "content": ENCRYPTED {
      "reason":"<failure reason detail>", // optional
      "did": "<the device id received from the request>",        
      "sdname": "<SD name for the domain created>",
      "teespaik": "<TEE SP AIK public key, BASE64 encoded>",
      "dsi": "<Updated TEE state, including all SD owned by 
        this TSM>"
    }
  }
}                         
             

In the response message, the following fields MUST be supplied.

did -
The SHA256 hash of the device TEE certificate. This shows the device ID explicitly to the receiving TSM.
teespaik -
The newly generated SP AIK public key for the given SP. This is an optional value if the device has had another domain for the SP that has triggered TEE SP AIK keypair for this specific SP.

There is possible extreme error case where TEE isn't reachable or the TEE final response generation itself fails. In this case, TSM should still receive a response from the OTrP Agent. OTrP Agent is able to detect such error from TEE. In this case, a general error response message should be returned, assuming OTrP Agent even doesn't know any content and information about the request message.

In other words, TSM should expect receive a TEE successfully signed JSON message, or a general "status" message.

{
  "CreateSDResponse": {
    "payload":"<CreateSDTBSResponse JSON above>",
    "protected": {
       "<BASE64URL of signing algorithm>"
    },
    "signature": "<signature contents signed by TEE device private 
                  key (BASE64URL)>"
  }
}
                        
             

A response message type "status" will be returned when TEE totally fails to respond. OTrP Agent is responsible to create this message.

{
  "status": {
     "result": "fail",
     "error-code": "ERR_TEE_UNKNOWN",
     "error-message": "TEE fails to respond"
  }
}
             

8.2.1.4. Error Conditions

An error may occur if a request isn't valid or the TEE runs into some error. The list of possible errors are the following. Refer to section Error Code List [errorcodelist] for detail causes and actions.

ERR_REQUEST_INVALID
ERR_UNSUPPORTED_MSG_VERSION
ERR_UNSUPPORTED_CRYPTO_ALG
ERR_DEV_STATE_MISMATCH
ERR_SD_ALREADY_EXIST
ERR_SD_NOT_FOUND
ERR_SPCERT_INVALID
ERR_TEE_FAIL
ERR_TEE_UNKNOWN
ERR_TSM_NOT_AUTHORIZED
ERR_TSM_NOT_TRUSTED

8.2.2. UpdateSD

This TSM initiated command can update a SP's SD that it manages for the following need. (a) Update SP signer certificate; (b) Add SP signer certificate when a SP uses multiple to sign TA binary; (c) Update SP ID.

The TSM presents the proof of the SD ownership to TEE, and includes related information in its signed message. The entire request is also encrypted for the end-to-end confidentiality.

8.2.2.1. UpdateSDRequest Message

The request message for UpdateSD has the following JSON format.

{
   "UpdateSDTBSRequest": {
     "ver": "1.0",
     "rid": "<unique request ID>",
     "tid": "<transaction ID>", // this may be from prior message
     "tee": "<TEE routing name from the DSI for the SD's target>",
     "nextdsi": "true | false",
     "dsihash": "<hash of DSI returned in the prior query>",
     "content": ENCRYPTED { // this piece of JSON will be encrypted
       "tsmid": "<TSMID associated with this SD>",
       "spid": "<SP ID>",
       "sdname": "<SD name for the domain to be updated>",        
       "changes": {
         "newsdname": "<Change the SD name to this new name>", 
                       // Optional
         "newspid": "<Change SP ID of the domain to this new value>", 
                       // Optional
         "spcert": ["<BASE64 encoded new SP signer cert to be added>"], 
                       // Optional
         "deloldspcert": ["<The SHA256 hex value of an old SP cert 
                    assigned into this SD that should be deleted >"], 
                       // Optional
         "renewteespaik": "true | false"
         }
     }
  }
}
             

In the message,

rid -
A unique value to identify this request
tid -
A unique value to identify this transaction. It can have the same value for the tid in the preceding GetDeviceStateRequest.
tee -
TEE ID returned from the previous response GetDeviceStateResponse
nextdsi -
Indicates whether the up to date Device State Information (DSI) should be returned in the response to this request.
dsihash -
The BASE64 encoded SHA256 hash value of the DSI data returned in the prior TSM operation with this target TEE. This value is always included such that a receiving TEE can check whether the device state has changed since its last query. It helps enforce SD update order in the right sequence without accidently overwrite an update that was done simultaneously.
content -
The "content" is a JSON encrypted message that includes actual input for the SD update. The standard JSON content encryption key (CEK) is used, and the CEK is encrypted by the target TEE's public key.
tsmid -
SD owner claim by TSM - A SD owned by a TSM will be associated with a trusted identifier defined as an attribute in the signer TSM certificate.
spid -
the identifier of the SP whose SD will be updated. This value is still needed because SD name is considered unique within a SP only.
sdname -
the name of the target SD to be updated.
changes -
its content consists of changes that should be updated in the given SD.
newsdname -
the new name of the target SD to be assigned if this value is present.
newspid -
the new SP ID of the target SD to be assigned if this value is present.
spcert -
a new TA signer certificate of this SP to be added to the SD if this is present.
deloldspcert -
a SP certificate assigned into the SD should be deleted if this is present. The value is the SHA256 fingerprint of the old SP certificate.
renewteespaik -
the value should be 'true' or 'false'. If it is present and the value is 'true', TEE should regenerate TEE SP AIK for this SD's owner SP. The newly generated TEE SP AIK for the SP must be returned in the response message of this request. If there are more than one SD for the SP, a new SPID for one of the domain will always trigger a new teespaik generation as if a new SP is introduced to the TEE.

Following the OTrP message template, the full request is signed message over the UpdateSDTBSRequest as follows.

{
  "UpdateSDRequest": {
    "payload":"<UpdateSDTBSRequest JSON above>",
    "protected":"<integrity-protected header contents>",
    "header":  <non-integrity-protected header contents>,
    "signature":"<signature contents signed by TSM private key>"
  }
}
             

TSM signer certificate is included in the "header" property.

8.2.2.2. Request processing requirements at a TEE

Upon receiving a request message UpdateSDRequest at a TEE, the TEE must validate a request:

  1. Validate the JSON request message
    • Validate JSON message signing
    • Validate that the request TSM certificate is chained to a trusted CA that the TEE embeds as its trust anchor. TSM certificate status check is generally not needed anymore in this request. The prior request should have validated the TSM certificate's revocation status
    • Compare dsihash with TEE cached last response DSI data to this TSM
    • Decrypt to get the plaintext of the content
    • Check that the target SD name is supplied
    • Check whether the requested SD exists
    • Check that the TSM owns this TSM by verifying TSMID in the SD matches TSM certificate's TSM ID attribute
    • Now the TEE is ready to carry out update listed in the "content" message

  2. Update action
    • If "newsdname" is given, replace the SD name for the SD to the new value
    • If "newspid" is given, replace the SP ID assigned to this SD with the given new value
    • If "spcert" is given, add this new SP certificate to the SD.
    • If "deloldspcert" is present in the content, check previously assigned SP certificates to this SD, and delete the one that matches the given certificate hash value.
    • If "renewteespaik" is given and has a value as "true", generate a new TEE SP AIK keypair, and replace the old one with this.
    • Generate new DSI data if the request asks for updated DSI
    • Now the TEE is ready to construct the response message

  3. Construct UpdateSDResponse message
    • Create raw content
      • Operation status
      • "did" or full signer certificate information,
      • TEE SP AIK public key if DSI isn't going to be included
      • Updated DSI data if requested if the request asks for it

    • The response message is encrypted with the same JWE CEK of the request without recreating a new content encryption key.
    • The encrypted message is signed with TEEpriv. The signer information ("did" or TEEcert) is encrypted.

  4. Deliver response message. (a) OTrP Agent returns this to the app; (b) The app passes this back to TSM
  5. TSM process. (a) TSM processes the response message; (b) TSM can look up signer certificate from device ID "did".

If a request is illegitimate or signature doesn't pass, a "status" property in the response will indicate the error code and cause.

8.2.2.3. UpdateSDResponse Message

The response message for a UpdateSDRequest contains the following content.

{  
  "UpdateSDTBSResponse": {
    "ver": "1.0",
    "status": "<operation result>",
    "rid": "<the request ID received>",
    "tid": "<the transaction ID received>",
    "content": ENCRYPTED {
      "reason":"<failure reason detail>", // optional
      "did": "<the device id hash>",        
      "cert": "<TEE certificate>", // optional 
      "teespaik": "<TEE SP AIK public key, BASE64 encoded>",
      "teespaiktype": "<TEE SP AIK key type: RSA or ECC>",
      "dsi": "<Updated TEE state, including all SD owned by 
        this TSM>"
    }
  }
}                         
             

In the response message, the following fields MUST be supplied.

did -
The request should have known the signer certificate of this device from a prior request. This hash value of the device TEE certificate serves as a quick identifier only. Full device certificate isn't necessary.
teespaik -
the newly generated SP AIK public key for the given SP if TEE SP AIK for the SP is asked to be renewed in the request. This is an optional value if "dsi" is included in the response, which will contain all up to date TEE SP AIK key pairs.

Similar to the template for the creation of the encrypted and signed CreateSDResponse, the final UpdateSDResponse looks like the following.

{
  "UpdateSDResponse": {
    "payload":"<UpdateSDTBSResponse JSON above>",
    "protected": {
        "<BASE64URL of signing algorithm>"
    },
    "signature": "<signature contents signed by TEE device private 
                  key (BASE64URL)>"
  }
}
                        
             

A response message type "status" will be returned when TEE totally fails to respond. OTrP Agent is responsible to create this message.

{
  "status": {
     "result": "fail",
     "error-code": "ERR_TEE_UNKNOWN",
     "error-message": "TEE fails to respond"
  }
}
             

8.2.2.4. Error Conditions

An error may occur if a request isn't valid or the TEE runs into some error. The list of possible errors are the following. Refer to section Error Code List [errorcodelist] for detail causes and actions.

ERR_REQUEST_INVALID
ERR_UNSUPPORTED_MSG_VERSION
ERR_UNSUPPORTED_CRYPTO_ALG
ERR_DEV_STATE_MISMATCH
ERR_SD_NOT_FOUND
ERR_SDNAME_ALREADY_USED
ERR_SPCERT_INVALID
ERR_TEE_FAIL
ERR_TEE_UNKNOWN
ERR_TSM_NOT_AUTHORIZED
ERR_TSM_NOT_TRUSTED

8.2.3. DeleteSD

A TSM sends a DeleteSDRequest message to TEE to delete a specified SD that it owns. A SD can be deleted only if there is no TA associated with this SD in the device. The request message can contain a flag to instruct TEE to delete all related TAs in a SD and then delete the SD.

The target TEE will operate with the following logic.

  1. Lookup given SD specified in the request message
  2. Check that the TSM owns the SD
  3. Check that the device state hasn't changed since the last operation
  4. Check whether there are TAs in this SD
  5. If TA exists in a SD, check whether the request instructs whether TA should be deleted. If the request instructs TEE to delete TAs, delete all TAs in this SD. If the request doesn't instruct the TEE to delete TAs, return an error "ERR_SD_NOT_EMPTY".
  6. Delete SD
  7. If this is the last SD of this SP, delete TEE SP AIK key

8.2.3.1. DeleteSDRequest Message

The request message for DeleteSD has the following JSON format.

{
   "DeleteSDTBSRequest": {
     "ver": "1.0",
     "rid": "<unique request ID>",
     "tid": "<transaction ID>", // this may be from prior message
     "tee": "<TEE routing name from the DSI for the SD's target>",
     "nextdsi": "true | false",
     "dsihash": "<hash of DSI returned in the prior query>",
     "content": ENCRYPTED { // this piece of JSON will be encrypted
       "tsmid": "<TSMID associated with this SD>",
       "sdname": "<SD name for the domain to be updated>",        
       "deleteta": "true | false"
     }
  }
}
             

In the message,

rid -
A unique value to identify this request
tid -
A unique value to identify this transaction. It can have the same value for the tid in the preceding GetDeviceStateRequest.
tee -
TEE ID returned from the previous response GetDeviceStateResponse
nextdsi -
Indicates whether the up to date Device State Information (DSI) should be returned in the response to this request.
dsihash -
The BASE64 encoded SHA256 hash value of the DSI data returned in the prior TSM operation with this target TEE. This value is always included such that a receiving TEE can check whether the device state has changed since its last query. It helps enforce SD update order in the right sequence without accidently overwrite an update that was done simultaneously.
content -
The "content" is a JSON encrypted message that includes actual input for the SD update. The standard JSON content encryption key (CEK) is used, and the CEK is encrypted by the target TEE's public key.
tsmid -
SD owner claim by TSM - A SD owned by a TSM will be associated with a trusted identifier defined as an attribute in the signer TSM certificate.
sdname -
the name of the target SD to be updated.
deleteta -
the value should be 'true' or 'false'. If it is present and the value is 'true', TEE should delete all TAs associated with the SD in the device.

Following the OTrP message template, the full request is signed message over the DeleteSDTBSRequest as follows.

{
    "DeleteSDRequest": {
        "payload":"<DeleteSDTBSRequest JSON above>",
        "protected":"<integrity-protected header contents>",
        "header":  <non-integrity-protected header contents>,
        "signature":"<signature contents signed by TSM private key>"
    }
}
             

TSM signer certificate is included in the "header" property.

8.2.3.2. Request processing requirements at a TEE

Upon receiving a request message DeleteSDRequest at a TEE, the TEE must validate a request:

  1. Validate the JSON request message
    • Validate JSON message signing
    • Validate that the request TSM certificate is chained to a trusted CA that the TEE embeds as its trust anchor. TSM certificate status check is generally not needed anymore in this request. The prior request should have validated the TSM certificate's revocation status
    • Compare dsihash with TEE cached last response DSI data to this TSM
    • Decrypt to get the plaintext of the content
    • Check that the target SD name is supplied
    • Check whether the requested SD exists
    • Check that the TSM owns this TSM by verifying TSMID in the SD matches TSM certificate's TSM ID attribute
    • Now the TEE is ready to carry out update listed in the "content" message

  2. Deletion action
    • Check TA existence in this SD
    • If "deleteta" is "true", delete all TAs in this SD. If the value of "deleteta" is "false" and some TA exists, return an error "ERR_SD_NOT_EMPTY"
    • Delete the SD
    • Delete TEE SP AIK key pair if this SD is the last one for the SP
    • Now the TEE is ready to construct the response message

  3. Construct DeleteSDResponse message
    • Create response content
      • Operation status
      • "did" or full signer certificate information,
      • Updated DSI data if requested if the request asks for it

    • The response message is encrypted with the same JWE CEK of the request without recreating a new content encryption key.
    • The encrypted message is signed with TEEpriv. The signer information ("did" or TEEcert) is encrypted.

  4. Deliver response message. (a) OTrP Agent returns this to the app; (b) The app passes this back to TSM
  5. TSM process. (a) TSM processes the response message; (b) TSM can look up signer certificate from device ID "did".

If a request is illegitimate or signature doesn't pass, a "status" property in the response will indicate the error code and cause.

8.2.3.3. DeleteSDResponse Message

The response message for a DeleteSDRequest contains the following content.

{  
  "DeleteSDTBSResponse": {
    "ver": "1.0",
    "status": "<operation result>",
    "rid": "<the request ID received>",
    "tid": "<the transaction ID received>",
    "content": ENCRYPTED {
      "reason":"<failure reason detail>", // optional
      "did": "<the device id hash>",        
      "dsi": "<Updated TEE state, including all SD owned by 
        this TSM>"
    }
  }
}                         
             

In the response message, the following fields MUST be supplied.

did -
The request should have known the signer certificate of this device from a prior request. This hash value of the device TEE certificate serves as a quick identifier only. Full device certificate isn't necessary.

The final DeleteSDResponse looks like the following.

{
  "DeleteSDResponse": {
    "payload":"<DeleteSDTBSResponse JSON above>",
    "protected": {
        "<BASE64URL of signing algorithm>"
    },
    "signature": "<signature contents signed by TEE device 
      private key (BASE64URL)>"
  }
}

A response message type "status" will be returned when TEE totally fails to respond. OTrP Agent is responsible to create this message.

{
  "status": {
     "result": "fail",
     "error-code": "ERR_TEE_UNKNOWN",
     "error-message": "TEE fails to respond"
  }
}
             

8.2.3.4. Error Conditions

An error may occur if a request isn't valid or the TEE runs into some error. The list of possible errors are the following. Refer to section Error Code List [errorcodelist] for detail causes and actions.

ERR_REQUEST_INVALID
ERR_UNSUPPORTED_MSG_VERSION
ERR_UNSUPPORTED_CRYPTO_ALG
ERR_DEV_STATE_MISMATCH
ERR_SD_NOT_EMPTY
ERR_SD_NOT_FOUND
ERR_TEE_FAIL
ERR_TEE_UNKNOWN
ERR_TSM_NOT_AUTHORIZED
ERR_TSM_NOT_TRUSTED

8.3. Trusted Application Management

This protocol doesn't introduce a TA container concept. All the TA authorization and management will be up to TEE implementation.

The following three TA management commands will be supported.

8.3.1. InstallTA

TA binary data can be from two sources:

  1. TSM supplies the signed TA binary
  2. Client Application supplies the TA binary

This specification considers only the first case where TSM supplies TA binary. When such a request is received by TEE, a SD is already created and is ready to take TA installation.

A TSM sends the following information in message InstallTARequest to a target TEE:

TEE processes command given by TSM to install TA into a SP's SD. It does the following:

8.3.1.1. InstallTARequest Message

The request message for InstallTA has the following JSON format.

{
  "InstallTATBSRequest": {
    "ver": "1.0",
    "rid": "<unique request ID>",
    "tid": "<transaction ID>",
    "tee": "<TEE routing name from the DSI for the SD's target>",
    "nextdsi": "true | false",
    "dsihash": "<hash of DSI returned in the prior query>",
    "content": ENCRYPTED { 
      "tsmid": "<TSM ID previously assigned to the SD>",
      "spid": "<SPID value>",
      "sdname": "<SD name for the domain to install the TA>",
      "spcert": "<BASE64 encoded SP certificate >", // optional
      "taid": "<TA identifier>"
    },
    "encrypted_ta": {
      "key": "<A 256-bit symmetric key encrypted by TEEspaik public 
              key>",
      "iv": "<hex of 16 random bytes>",
      "alg": "<encryption algoritm. AESCBC by default.",
      "ciphertadata": "<BASE64 encoded encrypted TA binary data>",
      "cipherpdata": "<BASE64 encoded encrypted TA personalization 
                      data>"
    }
  }
}
             

In the message,

rid -
A unique value to identify this request
tid -
A unique value to identify this transaction. It can have the same value for the tid in the preceding GetDeviceStateRequest.
tee -
TEE ID returned from the previous response GetDeviceStateResponse
nextdsi -
Indicates whether the up to date Device State Information (DSI) should be returned in the response to this request.
dsihash -
The BASE64 encoded SHA256 hash value of the DSI data returned in the prior TSM operation with this target TEE. This value is always included such that a receiving TEE can check whether the device state has changed since its last query. It helps enforce SD update order in the right sequence without accidently overwrite an update that was done simultaneously.
content -
The "content" is a JSON encrypted message that includes actual input for the SD update. The standard JSON content encryption key (CEK) is used, and the CEK is encrypted by the target TEE's public key.
tsmid -
SD owner claim by TSM - A SD owned by a TSM will be associated with a trusted identifier defined as an attribute in the signer TSM certificate.
spid -
SP identifier of the TA owner SP
spcert -
an optional field to specify SP certificate that signed the TA. This is sent if the SP has a new certificate that hasn't been previously registered with the target SD where the TA should be installed.
sdname -
the name of the target SD where the TA should be installed
encrypted_ta -
the message portion contains encrypted TA binary data and personalization data. The TA data encryption key is placed in "key", which is encrypted by the recipient's public key. The TA data encryption uses symmetric key based encryption such as AESCBC.

Following the OTrP message template, the full request is signed message over the InstallTATBSRequest as follows.

{
    "InstallTARequest": {
        "payload":"<InstallTATBSRequest JSON above>",
        "protected":"<integrity-protected header contents>",
        "header":  <non-integrity-protected header contents>,
        "signature":"<signature contents signed by TSM private key>"
    }
}
             

8.3.1.2. InstallTAResponse Message

The response message for a InstallTARequest contains the following content.

{  
  "InstallTATBSResponse": {
    "ver": "1.0",
    "status": "<operation result>",
    "rid": "<the request ID received>",
    "tid": "<the transaction ID received>",
    "content": ENCRYPTED {
      "reason":"<failure reason detail>", // optional
      "did": "<the device id hash>",        
      "dsi": "<Updated TEE state, including all SD owned by 
        this TSM>"
    }
  }
}                         
             

In the response message, the following fields MUST be supplied.

did -
the SHA256 hash of the device TEE certificate. This shows the device ID explicitly to the receiving TSM.

The final message InstallTAResponse looks like the following.

{
    "InstallTAResponse": {
        "payload":"<InstallTATBSResponse JSON above>",
        "protected": {
            "<BASE64URL of signing algorithm>"
        },
        "signature": "<signature contents signed by TEE device 
          private key (BASE64URL)>"
    }
}
                        
             

A response message type "status" will be returned when TEE totally fails to respond. OTrP Agent is responsible to create this message.

{
  "status": {
     "result": "fail",
     "error-code": "ERR_TEE_UNKNOWN",
     "error-message": "TEE fails to respond"
  }
}
             

8.3.1.3. Error Conditions

An error may occur if a request isn't valid or the TEE runs into some error. The list of possible errors are the following. Refer to section Error Code List [errorcodelist] for detail causes and actions.

ERR_REQUEST_INVALID
ERR_UNSUPPORTED_MSG_VERSION
ERR_UNSUPPORTED_CRYPTO_ALG
ERR_DEV_STATE_MISMATCH
ERR_SD_NOT_FOUND
ERR_TA_INVALID
ERR_TA_ALREADY_INSTALLED
ERR_TEE_FAIL
ERR_TEE_UNKNOWN
ERR_TEE_RESOURCE_FULL
ERR_TSM_NOT_AUTHORIZED
ERR_TSM_NOT_TRUSTED

8.3.2. UpdateTA

This TSM initiated command can update TA and its data in a SP's SD that it manages for the following purposes.

  1. Update TA binary
  2. Update TA's personalization data

The TSM presents the proof of the SD ownership to TEE, and includes related information in its signed message. The entire request is also encrypted for the end-to-end confidentiality.

TEE processes command given by TSM to update TA of a SP SD. It does the following:

8.3.2.1. UpdateTARequest Message

The request message for UpdateTA has the following JSON format.

{
  "UpdateTATBSRequest": {
    "ver": "1.0",
    "rid": "<unique request ID>",
    "tid": "<transaction ID>",
    "tee": "<TEE routing name from the DSI for the SD's target>",
    "nextdsi": "true | false",
    "dsihash": "<hash of DSI returned in the prior query>",
    "content": ENCRYPTED { 
      "tsmid": "<TSM ID previously assigned to the SD>",
      "spid": "<SPID value>",
      "sdname": "<SD name for the domain to be created>",
      "spcert": "<BASE64 encoded SP certificate >", // optional
      "taid": "<TA identifier>"
    },
    "encrypted_ta": {
      "key": "<A 256-bit symmetric key encrypted by TEEspaik public 
              key>",
      "iv": "<hex of 16 random bytes>",
      "alg": "<encryption algoritm. AESCBC by default.",
      "ciphernewtadata": "<Change existing TA binary to this new TA
          binary data(BASE64 encoded and encrypted)>",
      "ciphernewpdata": "<Change the existing data to this new TA
          personalization data(BASE64 encoded and encrypted)>" 
          // optional
    }
  }
}
             

In the message,

rid -
A unique value to identify this request
tid -
A unique value to identify this transaction. It can have the same value for the tid in the preceding GetDeviceStateRequest.
tee -
TEE ID returned from the previous response GetDeviceStateResponse
nextdsi -
Indicates whether the up to date Device State Information (DSI) should be returned in the response to this request.
dsihash -
The BASE64 encoded SHA256 hash value of the DSI data returned in the prior TSM operation with this target TEE. This value is always included such that a receiving TEE can check whether the device state has changed since its last query. It helps enforce SD update order in the right sequence without accidently overwrite an update that was done simultaneously.
content -
The "content" is a JSON encrypted message that includes actual input for the SD update. The standard JSON content encryption key (CEK) is used, and the CEK is encrypted by the target TEE's public key.
tsmid -
SD owner claim by TSM - A SD owned by a TSM will be associated with a trusted identifier defined as an attribute in the signer TSM certificate.
spid -
SP identifier of the TA owner SP
spcert -
an optional field to specify SP certificate that signed the TA. This is sent if the SP has a new certificate that hasn't been previously registered with the target SD where the TA should be installed.
sdname -
the name of the target SD where the TA should be updated
taid -
an identifier for the TA application to be updated
encrypted_ta -
the message portion contains new encrypted TA binary data and personalization data.

Following the OTrP message template, the full request is signed message over the UpdateTATBSRequest as follows.

              
              
{
    "UpdateTARequest": {
        "payload":"<UpdateTATBSRequest JSON above>",
        "protected":"<integrity-protected header contents>",
        "header":  <non-integrity-protected header contents>,
        "signature":"<signature contents signed by TSM private key>"
    }
}
             

8.3.2.2. UpdateTAResponse Message

The response message for a UpdateTARequest contains the following content.

{  
  "UpdateTATBSResponse": {
    "ver": "1.0",
    "status": "<operation result>",
    "rid": "<the request ID received>",
    "tid": "<the transaction ID received>",
    "content": ENCRYPTED {
      "reason":"<failure reason detail>", // optional
      "did": "<the device id hash>",        
      "dsi": "<Updated TEE state, including all SD owned by 
        this TSM>"
    }
  }
}                         
             

In the response message, the following fields MUST be supplied.

did -
the SHA256 hash of the device TEE certificate. This shows the device ID explicitly to the receiving TSM.

The final message UpdateTAResponse looks like the following.

{
    "UpdateTAResponse": {
        "payload":"<UpdateTATBSResponse JSON above>",
        "protected": {
            "<BASE64URL of signing algorithm>"
        },
        "signature": "<signature contents signed by TEE device 
          private key (BASE64URL)>"
    }
}
                        
             

A response message type "status" will be returned when TEE totally fails to respond. OTrP Agent is responsible to create this message.

{
  "status": {
     "result": "fail",
     "error-code": "ERR_TEE_UNKNOWN",
     "error-message": "TEE fails to respond"
  }
}
             

8.3.2.3. Error Conditions

An error may occur if a request isn't valid or the TEE runs into some error. The list of possible errors are the following. Refer to section Error Code List [errorcodelist] for detail causes and actions.

ERR_REQUEST_INVALID
ERR_UNSUPPORTED_MSG_VERSION
ERR_UNSUPPORTED_CRYPTO_ALG
ERR_DEV_STATE_MISMATCH
ERR_SD_NOT_FOUND
ERR_TA_INVALID
ERR_TA_NOT_FOUND
ERR_TEE_FAIL
ERR_TEE_UNKNOWN
ERR_TSM_NOT_AUTHORIZED
ERR_TSM_NOT_TRUSTED

8.3.3. DeleteTA

This operation defines OTrP messages that allow a TSM instruct a TEE to delete a TA for a SP in a given SD. A TEE will delete a TA from a SD and also TA data in the TEE. A Client Application cannot directly access TEE or OTrP Agent to delete a TA.

8.3.3.1. DeleteTARequest Message

The request message for DeleteTA has the following JSON format.

{
  "DeleteTATBSRequest": {
    "ver": "1.0",
    "rid": "<unique request ID>",
    "tid": "<transaction ID>",
    "tee": "<TEE routing name from the DSI for the SD's target>",
    "nextdsi": "true | false",
    "dsihash": "<hash of DSI returned in the prior query>",
    "content": ENCRYPTED { 
      "tsmid": "<TSM ID previously assigned to the SD>",
      "sdname": "<SD name of the TA>",
      "taid": "<the identifier of the TA to be deleted from the 
               specified SD>"
    }
  }
}
             

In the message,

rid -
A unique value to identify this request
tid -
A unique value to identify this transaction. It can have the same value for the tid in the preceding GetDeviceStateRequest.
tee -
TEE ID returned from the previous response GetDeviceStateResponse
nextdsi -
Indicates whether the up to date Device State Information (DSI) should be returned in the response to this request.
dsihash -
The BASE64 encoded SHA256 hash value of the DSI data returned in the prior TSM operation with this target TEE. This value is always included such that a receiving TEE can check whether the device state has changed since its last query. It helps enforce SD update order in the right sequence without accidently overwrite an update that was done simultaneously.
content -
The "content" is a JSON encrypted message that includes actual input for the SD update. The standard JSON content encryption key (CEK) is used, and the CEK is encrypted by the target TEE's public key.
tsmid -
SD owner claim by TSM - A SD owned by a TSM will be associated with a trusted identifier defined as an attribute in the signer TSM certificate.
sdname -
the name of the target SD where the TA is installed
taid -
an identifier for the TA application to be deleted

Following the OTrP message template, the full request is signed message over the DeleteTATBSRequest as follows.

              
              
{
    "DeleteTARequest": {
        "payload":"<DeleteTATBSRequest JSON above>",
        "protected":"<integrity-protected header contents>",
        "header":  <non-integrity-protected header contents>,
        "signature":"<signature contents signed by TSM 
            private key>"
    }
}
             

8.3.3.2. Request processing requirements at a TEE

TEE processes command given by TSM to delete a TA of a SP SD. It does the following:

  1. Validate the JSON request message
    • TEE validates TSM message authenticity
    • Decrypt to get request content
    • Lookup the SD and the TA with the given SD name and TA ID
    • Checks that the TSM owns the SD, and TA is installed in the SD
    • Checks DSI hash matches that the device state hasn't changed

  2. Deletion action
    • If all the above validation points pass, the TEE deletes the TA from the SD
    • The TEE may also delete all personalization data for the TA

  3. Construct DeleteTAResponse message.

If a request is illegitimate or signature doesn't pass, a "status" property in the response will indicate the error code and cause.

8.3.3.3. DeleteTAResponse Message

The response message for a DeleteTARequest contains the following content.

{  
  "DeleteTATBSResponse": {
    "ver": "1.0",
    "status": "<operation result>",
    "rid": "<the request ID received>",
    "tid": "<the transaction ID received>",
    "content": ENCRYPTED {
      "reason":"<failure reason detail>", // optional
      "did": "<the device id hash>",        
      "dsi": "<Updated TEE state, including all SD owned by 
        this TSM>"
    }
  }
}                         
             

In the response message, the following fields MUST be supplied.

did -
the SHA256 hash of the device TEE certificate. This shows the device ID explicitly to the receiving TSM.

The final message DeleteTAResponse looks like the following.

{
    "DeleteTAResponse": {
        "payload":"<DeleteTATBSResponse JSON above>",
        "protected": {
            "<BASE64URL of signing algorithm>"
        },
        "signature": "<signature contents signed by TEE device 
            private key (BASE64URL)>"
    }
}
                        
             

A response message type "status" will be returned when TEE totally fails to respond. OTrP Agent is responsible to create this message.

{
  "status": {
     "result": "fail",
     "error-code": "ERR_TEE_UNKNOWN",
     "error-message": "TEE fails to respond"
  }
}
             

8.3.3.4. Error Conditions

An error may occur if a request isn't valid or the TEE runs into some error. The list of possible errors are the following. Refer to section Error Code List [errorcodelist] for detail causes and actions.

ERR_REQUEST_INVALID
ERR_UNSUPPORTED_MSG_VERSION
ERR_UNSUPPORTED_CRYPTO_ALG
ERR_DEV_STATE_MISMATCH
ERR_SD_NOT_FOUND
ERR_TA_NOT_FOUND
ERR_TEE_FAIL
ERR_TEE_UNKNOWN
ERR_TSM_NOT_AUTHORIZED
ERR_TSM_NOT_TRUSTED

9. Response Messages a TSM May Expect

A TSM expects some feedback from a remote device when a request message is delivered to a device. The following three types of responses SHOULD be supplied.

Type 1:
Expect a valid TEE generated response message
A valid TEE signed response may contain errors detected by TEE, e.g. TSM is trusted but TSM supplied data is missing, for example, SP ID doesn't exist. TEE MUST be able to sign and encrypt.
If TEE isn't able to sign a response, TEE should returns an error to OTrP Agent without giving any other internal information. OTrP Agent will be generating the response.

Type 2:
OTrP Agent generated error message when TEE fails. OTrP Agent errors will be defined in this document.
A Type 2 message has the following format.
      {
        "OTrPAgentError": {
            "ver": "1.0",
            "rid": "",
            "tid": "",
            "errcode": "ERR_TEE_FAIL | ERR_TEE_BUSY"
        }
      }
           

Type 3:
OTrP Agent itself isn't reachable or fails. A Client Application is responsible to handle error and response TSM in its own way. This is out of scope for this specification.

10. Attestation Implementation Consideration

It is important to know that the state of a device is appropriate before trusting that a device is what it says it is. The attestation scheme for OTrP must also be able to cope with different TEEs, those that are OTrP compliant and those that use another mechanism. In the initial version, only one active TEE is assumed.

It is out of scope about how TSM and device implement the trust hierarchy verification. However, it is helpful to understand what each system provider should do in order to properly implement OTrP trust hierarchy.

In this section, we provide some implementation reference consideration.

10.1. OTrP Secure Boot Module

10.1.1. Attestation signer

It is proposed that attestation for OTrP is based on the SBM secure boot layer, and that further attestation is not performed within the TEE itself during security domain operations. The rationale is that the device boot process will be defined to start with a secure boot approach that, using eFuse, only releases attestation signing capabilities into the SBM once a secure boot has been established. In this way the release of the attestation signer can be considered the first "platform configuration metric", using TCG terminology.

10.1.2. SBM initial requirements

R1
SBM must be possible to load securely into the secure boot flow
R2
SBM must allow a public / private key pair to be generated during device manufacture
R3
The public key and certificate must be possible to store securely from tamper
R4
The private key must be possible to store encrypted at rest
R5
The private key must only be visible to the SBM when it is decrypted
R6
The SBM must be able to read a list of root and intermediate certificates that it can use to check certificate chains with. The list must be stored such that it cannot be tampered with
R7
Possible need to allow a TEE to access its unique TEE specific private key

10.2. TEE Loading

During boot SBM is required to start all of the ROOT TEEs. Before loading them the SBM must first determine whether the code sign signature of the TEE is valid. If TEE integrity is confirmed it may be started. The SBM must then be able to receive the identity certificate from the TEE (if that TEE is OTrP compliant). The identity certificate and keys will need to be baked into the TEE image, and therefore also covered by the code signer hash during the manufacture process. The private key for the identity certificate must be securely protected. The private key for a TEE identity must never be released no matter how the public key and certificate are released to the SBM.

Once the SBM has successfully booted a TEE and retrieved the identity certificate it will commit this to the platform configuration register (PCR) set, for later use during attestation. As a minimum the following data must be committed to the PCR for each TEE:

  1. Public key and certificate for the TEE
  2. TEE reference that can be used later by a TSM to identify this TEE

10.3. Attestation Hierarchy

The attestation hierarchy and seed required for TSM protocol operation must be built into the device at manufacture. Additional TEEs can be added post manufacture using the scheme proposed however it is outside of the current scope of this document to detail that.

It should be noted that the attestation scheme described is based on signatures. The only encryption that takes place is with eFuse to release the SBM signing key and later during protocol lifecycle management interchange with the TSM.

10.3.1. Attestation hierarchy establishment: manufacture

During manufacture the following steps are required:

  1. Device specific TFW key pair and certificate burnt into device, encrypted by eFuse. This key pair will be used for signing operations performed by SBM.
  2. TEE images are loaded and include a TEE instance specific key pair and certificate. The key pair and certificate are included in the image and covered by the code signing hash.
  3. The process for TEE images is repeated for any subordinate TEEs

10.3.2. Attestation hierarchy establishment: device boot

During device boot the following steps are required:

  1. Secure boot releases TFW private key by decrypting with eFuse
  2. SBM verifies the code-signing signature of the active TEE and places its TEE public key into a signing buffer, along with their reference for later access. For non-OTrP TEE, the SBM leaves the TEE public key field blank.
  3. SBM signs the signing buffer with TFW private key
  4. Each active TEE performs the same operation as SBM, building up their own signed buffer containing subordinate TEE information.

10.3.3. Attestation hierarchy establishment: TSM

Before a TSM can begin operation in the marketplace it must obtain a TSM key pair and certificate (TSMpub, TSMpriv) from a CA that is registered in the trust store of the TEE. In this way, the TEE can check the intermediate and root CA and verify that it trusts this TSM to perform operations on the TEE.

11. Acknowledgements

We thank Alin Mutu for his contribution to many discussion that helped to design the trust flow mechanisms, and the creation of the flow diagrams. Alin has contributed the context diagram and brought good point in trust establishment.

We also thank the following people for their input, review, and discussions that have greatly helped to shape the document: Sangsu Baek, Marc Canel, Roger Casals, Rob Coombs, Lubna Dajani, and Richard Parris.

12. Contributors

Brian Witten
Symantec
900 Corporate Pointe
Culver City, CA 90230
USA

Email: brian_witten@symantec.com
         
Tyler Kim
Solacia
5F, Daerung Post Tower 2, 306 Digital-ro
Seoul 152-790
Korea

Email: tkkim@sola-cia.com 
         

13. IANA Considerations

The error code listed in the next section will be registered.

13.1. Error Code List

This section lists error codes that could be reported by a TA or TEE in a device in responding a TSM request.

ERR_DEV_STATE_MISMATCH -
TEE will return this error code if DSI hash value from TSM doesn't match with that of device's current DSI.
ERR_SD_ALREADY_EXIST -
This error will occur if SD to be created already exist in the TEE.
ERR_SD_NOT_EMPTY -
This is reported if a target SD isn't empty.
ERR_SDNAME_ALREADY_USED
TEE will return this error code if new SD name already exists in the namespace of TSM in the TEE.
ERR_REQUEST_INVALID -
This error will occur if the TEE meets the following conditions with a request message: (1) The request from a TSM has an invalid message structure; mandatory information is absent in the message. undefined member or structure is included. (2) TEE fails to verify signature of the message or fails to decrypt its contents. (3) etc.
ERR_SPCERT_INVALID -
If new SP certificate for the SD to be updated is not valid, then TEE will return this error code.
ERR_TA_ALREADY_INSTALLED -
while installing TA, TEE will return this error if the TA already has been installed in the SD.
ERR_TA_INVALID -
This error will occur when TEE meets any of following conditions while checking validity of TA: (1) TA binary has a format that TEE can't recognize. (2) TEE fails to decrypt the encoding of TA binary and personalization data. (3) If SP isn't registered with the SP SD where TA will be installed. (4) etc.
ERR_TA_NOT_FOUND -
This error will occurs when target TA doesn't exist in the SD.
ERR_TEE_BUSY -
The device TEE is busy. The request should be generally sent later to retry.
ERR_TEE_FAIL -
TEE fails to respond to a TSM request. The OTrP Agent will construct an error message in responding the TSM's request. And also if TEE fails to process a request because of its internal error, it will return this error code.
ERR_TEE_RESOURCE_FULL -
This error is reported when a device resource isn't available anymore such as storage space is full.
ERR_TEE_UNKNOWN -
This error will occur if the receiver TEE is not supposed to receive the request. That will be determined by checking TEE name or device id in the request message.
ERR_TFW_NOT_TRUSTED -
TEE may concern the underlying device firmware is trustworthy. If TEE determines TFW is not trustworthy, then this error will occur.
ERR_TSM_NOT_TRUSTED -
Before processing a request, TEE needs to make sure whether the sender TSM is trustworthy by checking the validity of TSM certificate etc. If TEE finds TSM is not reliable, then it will return this error code.
ERR_UNSUPPORTED_CRYPTO_ALG -
This error will occur if TEE receives a request message encoded with cryptographic algorithms that TEE doesn't support.
ERR_UNSUPPORTED_MSG_VERSION -
This error will occur if TEE receives the version of message that TEE can't deal with.

14. Security Consideration

14.1. Cryptographic Strength

The strength of the cryptographic algorithms, using the measure of 'bits of security' defined in NIST SP800-57 allowed for the OTrP protocol is:

The available algorithms and key sizes specified in this document are based on industry standards. Over time the recommended or allowed cryptographic algorithms may change. It is important that the OTrP protocol allows for crypto-agility.

14.2. Message Security

OTrP messages between the TSM and TEE are protected by message security using JWS and JWE. The 'Basic protocol profile' section of this document describes the algorithms used for this. All OTrP TEE devices and OTrP TSMs must meet the requirements of the basic profile. In the future additional 'profiles' can be added.

PKI is used to ensure that the TEE will only communicate with a trusted TSM, and to ensure that the TSM will only communicate with a trusted TEE.

14.3. TEE Attestation

It is important that the TSM can trust that it is talking to a trusted TEE. This is achieved through attestation. The TEE has a private key and certificate built into it at manufacture, which is used to sign data supplied by the TSM. This allows the TSM to verify that the TEE is trusted.

It is also important that the TFW (trusted firmware) can be checked. The TFW has a private key and certificate built into it at manufacturer, which allows the TEE to check that that the TFW is trusted.

The GetDeviceState message therefore allows the TSM to check that it trusts the TEE, and the TEE at this point will check whether it trusts the TFW.

14.4. TA Protection

TA will be delivered in an encrypted form. This encryption is an additional layer within the message encryption described in the 'Basic protocol profile' section of this document. The TA binary is encrypted for each target device with the device's TEE SP AIK public key. A TSM may do this encryption or provides the TEE SP AIK public key to a SP such that the SP encrypts the encrypted TA to TSM for distribution to TEE.

The encryption algorithm can use a randomly AES 256 key "taek" with a 16 byte random IV, and the "taek" is encrypted by the "TEE SP AIK public key". The following encrypted TA data structure is expected by TEE:

"encrypted_ta_bin": {
  "key": "<A 256-bit symmetric key encrypted by TEE SP AIK public 
           key>",
  "iv": <hex of 16 random bytes>",
  "alg": "AESCBC",
  "cipherdata": "<BASE64 encoded encrypted TA binary data>"
}
         

14.5. TA Personalization Data

A SP or TSM can supply personalization data for a TA to initialize for a device. Such data is passed through InstallTA command from TSM. The personalization data itself is (or can be) opaque to the TSM. The data can be from the SP without being revealed to the TSM. The data is sent in encrypted manner in a request to a device such that only the device can decrypt. A device's TEE SP AIK public key for a SP is used to encrypt the data.

"encrypted_ta_data": { // "TA personalization data" 
    "key": "<A 256-bit symmetric key encrypted by TEE SP AIK public
            key>", 
    "iv": "<hex of 16 random bytes>",
    "alg": "AESCBC",
    "cipherdata": "<BASE64 encoded encrypted TA personalization 
                   data>" 
  }
         

14.6. TA trust check at TEE

A TA binary is signed by a TA signer certificate. This TA signing certificate/private key belongs to the SP, and may be self-signed (i.e. it need not participate in a trust hierarchy). It is the responsibility of the TSM to only allow verified TAs from trusted SPs into the system. Delivery of that TA to the TEE is then the responsibility of the TEE, using the security mechanisms provided by the OTrP protocol.

We allow a way for application to check trustworthy of a TA. OTrP Agent will have a function to allow an application query the metadata of a TA.

An application in the Rich O/S may perform verification of the TA by verifying the signature of the TA. The OTRPService.getTAInformation() function is available to return TEE supplied TA signer and TSM signer information to the application. An application can do additional trust check on the certificate returned for this TA. It may trust TSM, or require additional SP signer trust chaining.

14.7. One TA Multiple SP Case

A TA for different SP must have different identifier. A TA will be installed in different SD for the respective SP.

14.8. OTrP Agent Trust Model

An OTrP Agent could be malware in the vulnerable Android OS. A Client Application will connect its TSM provider for required TA installation. It gets command messages from TSM, and passes the message to the OTrP Agent.

The OTrP protocol is a conduit for enabling the TSM to communicate with the device's TEE to manage SDs and TAs. All TSM messages are signed and sensitive data is encrypted such that the OTrP Agent cannot modify or capture sensitive data.

14.9. OCSP Stapling Data for TSM signed messages

The GetDeviceStateRequest message from TSM to TEE shall include OCSP stapling data for the TSM's signer certificate and that for intermediate CA certificates up to the root certificate so that the TEE side can verify the signer certificate's revocation status.

Certificate revocation status check on a TA signer certificate is optional by a TEE. A TSM is generally expected to do proper TA application vetting and its SP signer trust validation. A TEE will trust a TA signer certificate's validation status done by a TSM when it trusts the TSM.

14.10. Data protection at TSM and TEE

The TEE implementation provides protection of data on the device. It is the responsibility of the TSM to protect data on its servers.

14.11. Privacy consideration

Devices are issued with a unique TEE certificate to attest a device validity. This uniqueness also creates a privacy and tracking risk that must be mitigated.

The TEE will only release the TEE certificate to a trusted TSM (it must verify the TSM certificate before proceeding). The OTrP protocol is designed such that only the TSM can obtain the TEE device certificate and firmware certificate - the GetDeviceState message requires signature checks to validate the TSM is trusted, and then delivers the device's certificate(s) encrypted such that only that TSM may decrypt the response. A Client Application will never see device certificate.

A SP specific TEE SP AIK (TEE SP Anonymous Key) is generated by the protocol for Client Applications. This provides a way for the Client Application to validate data sent from the TEE without requiring the TEE device certificate to be released to the client device rich O/S , and to optionally allow an SP to encrypt a TA for a target device without the SP needing to be supplied the TEE device certificate.

14.12. Threat mitigation

A rogue application may perform excessive TA loading. OTrP Agent implementation should protect against excessive calls.

Rogue applications may request excessive SD creation request. The TSM is responsible to ensure this is properly guarded against.

Rogue OTrP Agent could replay or send TSM messages out of sequence:e.g. TSM sends update1 and update2. OTrP Agent replays update2 and update1 again, create unexpected result that client wants. "dsihash" is used to mitigate this. The TEE MUST make sure it stores DSI state and checks DSI state matches before it does another update.

Concurrent calls from TSM to TEE should be handled properly by a TEE. It is up to the device to manage concurrency to the TEE. If multiple concurrent TSM operations take place these could fail due "dsihash" being modified by another concurrent operation. If locking is implemented on the client, this must be done in such a way that one application cannot lock other applications from using the TEE, except for a short term duration of the TSM operation taking place. For example, an OTrP operation that starts but never completes (e.g. loss of connectivity) must not prevent subsequent OTrP messages from being executed.

14.13. Compromised CA

If a root CA for TSM certificates is found compromised, some TEE trust anchor update mechanism should be devised. A compromised intermediate CA is covered by OCSP stapling and OCSP validation check in the protocol. A TEE should validate certificate revocation about a TSM certificate chain.

If the root CA of some TEE device certificates is compromised, these devices might be rejected by TSM, which is a decision of TSM implementation and policy choice. Any intermediate CA for TEE device certificates should be validated by TSM with common CRL or OCSP method.

14.14. Compromised TSM

The TEE should use validation of the supplied TSM certificates and OCSP stapled data to validate that the TSM is trustworthy.

Since PKI is used, the integrity of the clock within the TEE determines the ability of the TEE to reject an expired TSM certificate, or revoked TSM certificate. Since OCSP stapling includes signature generation time, certificate validity dates are compared to the current time.

14.15. Certificate renewal

TFW and TEE device certificates are expected to be long lived, longer than the lifetime of a device. A TSM certificate usually has a moderate lifetime of 2 to 5 years. TSM should get renewed or rekeyed certificates.The root CA certificates for TSM, which is embedded into the trust anchor store in a device, should have long lifetime that don't require device trust anchor update. On the other hand, it is imperative that OEM or device providers plan for support of trust anchor update in their shipped devices.

15. References

15.1. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC7515] Jones, M., Bradley, J. and N. Sakimura, "JSON Web Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May 2015.
[RFC7516] Jones, M. and J. Hildebrand, "JSON Web Encryption (JWE)", RFC 7516, DOI 10.17487/RFC7516, May 2015.
[RFC7517] Jones, M., "JSON Web Key (JWK)", RFC 7517, DOI 10.17487/RFC7517, May 2015.
[RFC7518] Jones, M., "JSON Web Algorithms (JWA)", RFC 7518, DOI 10.17487/RFC7518, May 2015.

15.2. Informative References

[GPTEE] Global Platform, "Global Platform, GlobalPlatform Device Technology: TEE System Architecture, v1.0", 2013.

Appendix A. Sample Messages

A.1. Sample Security Domain Management Messages

A.1.1. Sample GetDeviceState

A.1.1.1. Sample GetDeviceStateRequest

TSM builds a "GetDeviceStateTBSRequest" message.

{
    "GetDeviceStateTBSRequest": {
      "ver": "1.0",
      "rid": "8C6F9DBB-FC39-435c-BC89-4D3614DA2F0B",
      "tid": "4F454A7F-002D-4157-884E-B0DD1A06A8AE",
      "ocspdat": "c2FtcGxlIG9jc3BkYXQgQjY0IGVuY29kZWQgQVNOMQ==",
      "icaocspdat": "c2FtcGxlIGljYW9jc3BkYXQgQjY0IGVuY29kZWQgQVNOMQ==",
      "supportedsigalgs": "RS256"
    }
}
             

TSM signs "GetDeviceStateTBSRequest", creating "GetDeviceStateRequest"

{
  "GetDeviceStateRequest": {
    "payload":"
    ewoJIkdldERldmljZVN0YXRlVEJTUmVxdWVzdCI6IHsKCQkidmVyIjogIjEuMCIsCgkJ
    InJpZCI6IHs4QzZGOURCQi1GQzM5LTQzNWMtQkM4OS00RDM2MTREQTJGMEJ9LAoJCSJ0
    aWQiOiAiezRGNDU0QTdGLTAwMkQtNDE1Ny04ODRFLUIwREQxQTA2QThBRX0iLAoJCSJv
    Y3NwZGF0IjogImMyRnRjR3hsSUc5amMzQmtZWFFnUWpZMElHVnVZMjlrWldRZ1FWTk9N
    UT09IiwKCQkiaWNhb2NzcGRhdCI6ICJjMkZ0Y0d4bElHbGpZVzlqYzNCa1lYUWdRalkw
    SUdWdVkyOWtaV1FnUVZOT01RPT0iLAoJCSJzdXBwb3J0ZWRzaWdhbGdzIjogIlJTMjU2
    IgoJfQp9",
    "protected": "eyJhbGciOiJSUzI1NiJ9",
    "header": {
      "x5c": ["ZXhhbXBsZSBBU04xIHNpZ25lciBjZXJ0aWZpY2F0ZQ==",
              "ZXhhbXBsZSBBU04xIENBIGNlcnRpZmljYXRl"]
    },
    "signature":"c2FtcGxlIHNpZ25hdHVyZQ"
  }
}
             

A.1.1.2. Sample GetDeviceStateResponse

TSM sends "GetDeviceStateRequest" to OTrP Agent

OTrP Agent obtains "dsi" from each TEE. (in this example there is a single TEE).

TEE obtains signed "fwdata" from firmware

TEE builds "dsi" - summarizing device state of TEE

{
  "dsi": {
    "tfwdata": {
      "tbs": "ezRGNDU0QTdGLTAwMkQtNDE1Ny04ODRFLUIwREQxQTA2QThBRX0=",
      "cert": "ZXhhbXBsZSBGVyBjZXJ0aWZpY2F0ZQ==",
      "sigalg": "RS256",
      "sig": "c2FtcGxlIEZXIHNpZ25hdHVyZQ=="
    },
    "tee": {
      "name": "Primary TEE",
      "ver": "1.0",
      "cert": "c2FtcGxlIFRFRSBjZXJ0aWZpY2F0ZQ==",
      "cacert": [
        "c2FtcGxlIENBIGNlcnRpZmljYXRlIDE=",
        "c2FtcGxlIENBIGNlcnRpZmljYXRlIDI="
      ],
    "sdlist": {
      "cnt": "1",
      "sd": [
      {
        "name": "default.acmebank.com",
        "spid": "acmebank.com",
        "talist": [
          {
            "taid": "acmebank.secure.banking",
            "taname": "Acme secure banking app"
          },
          {
            "taid": "acmebank.loyalty.rewards",
            "taname": "Acme loyalty rewards app"
          }
        ]
      }
      ]
    },
    "teeaiklist": [
      {
        "spaik": "c2FtcGxlIEFTTjEgZW5jb2RlZCBQS0NTMSBwdWJsaWNrZXk=",
        "spaiktype": "RSA",
        "spid": "acmebank.com"
      }
    ]
    }
  }
}
             

TEE encrypts "dsi", and embeds into "GetDeviceTEEStateTBSResponse" message

{
  "GetDeviceTEEStateTBSResponse": {
    "ver": "1.0",
    "status": "pass",
    "rid": "{8C6F9DBB-FC39-435c-BC89-4D3614DA2F0B}",
    "tid": "{4F454A7F-002D-4157-884E-B0DD1A06A8AE}",
    "signerreq":"false",
    "edsi": {
      "protected": "eyJlbmMiOiJBMTI4Q0JDLUhTMjU2In0K",
      "recipients": [
        {
          "header": {
          "alg": "RSA1_5"
        },
        "encrypted_key":
        "
        QUVTMTI4IChDRUspIGtleSwgZW5jcnlwdGVkIHdpdGggVFNNIFJTQSBwdWJsaWMg
        a2V5LCB1c2luZyBSU0ExXzUgcGFkZGluZw"
        }
      ],
      "iv": "ySGmfZ69YlcEilNr5_SGbA",
      "ciphertext":
      "
      c2FtcGxlIGRzaSBkYXRhIGVuY3J5cHRlZCB3aXRoIEFFUzEyOCBrZXkgZnJvbSByZW
      NpcGllbnRzLmVuY3J5cHRlZF9rZXk",
      "tag": "c2FtcGxlIGF1dGhlbnRpY2F0aW9uIHRhZw"
    }
  }
}
             

TEE signs "GetDeviceTEEStateTBSResponse" and returns to OTrP Agent. OTrP Agent encodes "GetDeviceTEEStateResponse" into an array to form "GetDeviceStateResponse"

{
  "GetDeviceStateResponse": [
    {
      "GetDeviceTEEStateResponse": {
        "payload":
        "
        ewogICJHZXREZXZpY2VURUVTdGF0ZVRCU1Jlc3BvbnNlIjogewogICAgInZlciI6
        ICIxLjAiLAogICAgInN0YXR1cyI6ICJwYXNzIiwKICAgICJyaWQiOiAiezhDNkY5
        REJCLUZDMzktNDM1Yy1CQzg5LTREMzYxNERBMkYwQn0iLAogICAgInRpZCI6ICJ7
        NEY0NTRBN0YtMDAyRC00MTU3LTg4NEUtQjBERDFBMDZBOEFFfSIsCgkic2lnbmVy
        cmVxIjoiZmFsc2UiLAogICAgImVkc2kiOiB7CiAgICAgICJwcm90ZWN0ZWQiOiAi
        ZXlKbGJtTWlPaUpCTVRJNFEwSkRMVWhUTWpVMkluMEsiLAogICAgICAicmVjaXBp
        ZW50cyI6IFsKICAgICAgICB7CiAgICAgICAgICAiaGVhZGVyIjogewogICAgICAg
        ICAgImFsZyI6ICJSU0ExXzUiCiAgICAgICAgfSwKICAgICAgICAiZW5jcnlwdGVk
        X2tleSI6CiAgICAgICAgIgogICAgICAgIFFVVlRNVEk0SUNoRFJVc3BJR3RsZVN3
        Z1pXNWpjbmx3ZEdWa0lIZHBkR2dnVkZOTklGSlRRU0J3ZFdKc2FXTWcKICAgICAg
        ICBhMlY1TENCMWMybHVaeUJTVTBFeFh6VWdjR0ZrWkdsdVp3IgogICAgICAgIH0K
        ICAgICAgXSwKICAgICAgIml2IjogInlTR21mWjY5WWxjRWlsTnI1X1NHYkEiLAog
        ICAgICAiY2lwaGVydGV4dCI6CiAgICAgICIKICAgICAgYzJGdGNHeGxJR1J6YVNC
        a1lYUmhJR1Z1WTNKNWNIUmxaQ0IzYVhSb0lFRkZVekV5T0NCclpYa2dabkp2YlNC
        eVpXCiAgICAgIE5wY0dsbGJuUnpMbVZ1WTNKNWNIUmxaRjlyWlhrIiwKICAgICAg
        InRhZyI6ICJjMkZ0Y0d4bElHRjFkR2hsYm5ScFkyRjBhVzl1SUhSaFp3IgogICAg
        fQogIH0KfQ",
        "protected": "eyJhbGciOiJSUzI1NiJ9",
        "signature": "c2FtcGxlIHNpZ25hdHVyZQ"
      }
    }
  ]
}
             

TEE returns "GetDeviceStateResponse" back to OTrP Agent, which returns message back to TSM.

A.1.2. Sample CreateSD

A.1.2.1. Sample CreateSDRequest

{
  "CreateSDTBSRequest": { 
    "ver":"1.0",
    "rid":"req-01",
    "tid":"tran-01",
    "tee":"SecuriTEE",
    "nextdsi":"false",
    "dsihash":"Iu-c0-fGrpMmzbbtiWI1U8u7wMJE7IK8wkJpsVuf2js",
    "content":{   
      "spid":"bank.com",
      "sdname":"sd.bank.com",
      "spcert":"MIIDFjCCAn-
      gAwIBAgIJAIk0Tat0tquDMA0GCSqGSIb3DQEBBQUAMGwxCzAJBgNVBAYTAktSMQ4wD
      AYDVQQIDAVTZW91bDESMBAGA1UEBwwJR3Vyby1kb25nMRAwDgYDVQQKDAdTb2xhY2l
      hMRAwDgYDVQQLDAdTb2xhY2lhMRUwEwYDVQQDDAxTb2xhLWNpYS5jb20wHhcNMTUwN
      zAyMDg1MTU3WhcNMjAwNjMwMDg1MTU3WjBsMQswCQYDVQQGEwJLUjEOMAwGA1UECAw
      FU2VvdWwxEjAQBgNVBAcMCUd1cm8tZG9uZzEQMA4GA1UECgwHU29sYWNpYTEQMA4GA
      1UECwwHU29sYWNpYTEVMBMGA1UEAwwMU29sYS1jaWEuY29tMIGfMA0GCSqGSIb3DQE
      BAQUAA4GNADCBiQKBgQDYWLrFf2OFMEciwSYsyhaLY4kslaWcXA0hCWJRaFzt5mU-
      lpSJ4jeu92inBbsXcI8PfRbaItsgW1TD1Wg4gQH4MX_YtaBoOepE--
      3JoZZyPyCWS3AaLYWrDmqFXdbzaO1i8GxB7zz0gWw55bZ9jyzcl5gQzWSqMRpx_dca
      d2SP2wIDAQABo4G_MIG8MIGGBgNVHSMEfzB9oXCkbjBsMQswCQYDVQQGEwJLUjEOMA
      wGA1UECAwFU2VvdWwxEjAQBgNVBAcMCUd1cm8tZG9uZzEQMA4GA1UECgwHU29sYWNp
      YTEQMA4GA1UECwwHU29sYWNpYTEVMBMGA1UEAwwMU29sYS1jaWEuY29tggkAiTRNq3
      S2q4MwCQYDVR0TBAIwADAOBgNVHQ8BAf8EBAMCBsAwFgYDVR0lAQH_BAwwCgYIKwYB
      BQUHAwMwDQYJKoZIhvcNAQEFBQADgYEAEFMhRwEQ-
      LDa9O7P1N0mcLORpo6fW3QuJfuXbRQRQGoXddXMKazI4VjbGaXhey7Bzvk6TZYDa-
      GRiZby1J47UPaDQR3UiDzVvXwCOU6S5yUhNJsW_BeMViYj4lssX28iPpNwLUCVm1QV
      THILI6afLCRWXXclc1L5KGY290OwIdQ",
      "tsmid":"tsm_x.acme.com",
      "did":"zAHkb0-SQh9U_OT8mR5dB-tygcqpUJ9_x07pIiw8WoM"
    }
  }
}
             

Here is a sample message after the content is encrypted and encoded

{
  "CreateSDRequest": {
  "payload":"
  eyJDcmVhdGVTRFRCU1JlcXVlc3QiOnsidmVyIjoiMS4wIiwicmlkIjoicmVxLTAxIiwidG
  lkIjoidHJhbi0wMSIsInRlZSI6IlNlY3VyaVRFRSIsIm5leHRkc2kiOiJmYWxzZSIsImRz
  aWhhc2giOiIyMmVmOWNkM2U3YzZhZTkzMjZjZGI2ZWQ4OTYyMzU1M2NiYmJjMGMyNDRlYz
  gyYmNjMjQyNjliMTViOWZkYTNiIiwiY29udGVudCI6eyJwcm90ZWN0ZWQiOiJlLUtBbkdW
  dVktS0FuVHJpZ0p4Qk1USTRRMEpETFVoVE1qVTI0b0NkZlEiLCJyZWNpcGllbnRzIjpbey
  JoZWFkZXIiOnsiYWxnIjoiUlNBMV81In0sImVuY3J5cHRlZF9rZXkiOiJTUzE2NTl4Q2FJ
  c1dUeUlsVTZPLUVsZzU4UUhvT1pCekxVRGptVG9vanBaWE54TVpBakRMcWtaSTdEUzhOVG
  FIWHcxczFvZjgydVhsM0d6NlVWMkRoZDJ3R2l6Y2VEdGtXc1RwZDg4QVYwaWpEYTNXa3lk
  dEpSVmlPOGdkSlEtV29NSUVJRUxzVGthblZCb25wQkF4ZHE0ckVMbl9TZlliaFg4Zm9ub2
  gxUVUifV0sIml2IjoiQXhZOERDdERhR2xzYkdsamIzUm9aUSIsImNpcGhlcnRleHQiOiI1
  bmVWZXdndm55UXprR3hZeWw5QlFrZTJVNjVaOHp4NDdlb3NzM3FETy0xY2FfNEpFY3NLcj
  ZhNjF5QzBUb0doYnJOQWJXbVRSemMwSXB5bTF0ZjdGemp4UlhBaTZBYnVSM2gzSUpRS1Bj
  UUVvRUlkZ2tWX0NaZTM2eTBkVDBpRFBMclg0QzFkb0dmMEdvaWViRC1yVUg1VUtEY3BsTW
  9lTjZvUnFyd0dnNUhxLTJXM3B4MUlzY0h4SktRZm11dkYxMTJ4ajBmZFNZX0N2WFE1NTJr
  TVRDUW1ZbzRPaGF2R0ZvaG9TZVVnaGZSVG1LYWp3OThkTzdhREdrUEpRUlBtYVVHWllEMW
  JXd01nMXFRV3RPd19EZlIyZDNzTzVUN0pQMDJDUFprVXBiQ3dZYVcybW9HN1c2Zlc2U3V5
  Q2lpd2pQWmZSQmIzSktTVTFTd1kxYXZvdW02OWctaDB6by12TGZvbHRrWFV2LVdPTXZTY0
  JzR25NRzZYZnMzbXlTWnJ1WTNRR09wVVRzdjFCQ0JqSTJpdjkwb2U2aXFCcVpxQVBxbzdi
  ajYwVlJGQzZPTlNLZExGQTIyU3pqRHo1dmtnTXNEaHkwSzlDeVhYN1Z6MkNLTXJvQjNiUE
  xFZF9abTZuVWlkTFN5cVJ5cXJxTmVnN1lmQng3aV93X0dzRW9rX1VYZXd6RGtneHp6RjZj
  XzZ6S0s3UFktVnVmYUo0Z2dHZmlpOHEwMm9RZ1VEZTB2Vm1FWDc0c2VQX2RxakVpZVVOYm
  xBZE9sS2dBWlFGdEs4dy1xVUMzSzVGTjRoUG9yeDc2b3lPVUpOQTVFZVV2Qy1jR2tMcTNQ
  UG1GRmQyaUtOTElCTEJzVWl6c1h3RERvZVA5SmktWGt5ZEQtREN1SHdpcno0OEdNNWVLSj
  Q5WVdqRUtFQko2T01NNUNmZHZ4cDNmVG1uUTdfTXcwZ3FZVDRiOUJJSnBfWjA3TTctNUpE
  emg0czhyU3dsQzFXU3V2RmhRWlJCcXJtX2RaUlRIb0VaZldXc1VCSWVNWWdxNG1zb0JqTj
  NXSzhnRWYwZGI5a3Z6UG9LYmpJRy10UUE2R2l1X3pHaFVfLXFBV1lLemVKMDZ6djRIWlBO
  dHktQXRyTGF0WGhtUTdOQlVrX0hvbjdOUWxhU1g1ZHVNVmN4bGs1ZHVrWFZNMDgxa09wYV
  kzbDliQVFfYVhTM0FNaFFTTVVsT3dnTDZJazFPYVpaTGFMLUE3ejlITnlESmFEWTVhakZK
  TWFDV1lfOG94YlNoQUktNXA2MmNuT0xzV0dNWWNKTlBGVTZpcWlMR19oc3JfNlNKMURhbD
  VtQ0YycnBJLUItMlhuckxZR01ZS0NEZ2V2dGFnbi1DVUV6RURwR3ozQ2VLcWdQU0Vqd3BK
  N0M3NXduYTlCSmtTUkpOdDNla3hoWElrcnNEazRHVVpMSDdQYzFYZHdRTXhxdWpzNmxJSV
  EycjM1NWEtVkotWHdPcFpfY3RPdW96LTA4WHdYQ3RkTEliSFFVTG40RjlMRTRtanU0dUxS
  bjNSc043WWZ1S3dCVmVEZDJ6R3NBY0s5SVlDa3hOaDk3dDluYW1iMDZqSXVoWXF5QkhWRU
  9nTkhici1rMDY1bW9OVk5lVVUyMm5OdVNKS0ZxVnIxT0dKNGVfNXkzYkNwTmxTeEFPV1Bn
  RnJzU0Flc2JJOWw4eVJtVTAwenJYdGc4OWt5SjlCcXN2eXA1RE8wX2FtS1JyMXB1MVJVWF
  lFZzB2ampKS1FSdDVZbXRUNFJzaWpqdGRDWDg3UUxJaUdSY0hDdlJzUzZSdDJESmNYR1ht
  UGQyc0ZmNUZyNnJnMkFzX3BmUHN3cnF1WlAxbVFLc3RPMFVkTXpqMTlyb2N1NHVxVXlHUD
  lWWU54cHVnWVdNSjRYb1dRelJtWGNTUEJ4VEtnenFPS2s3UnRzWWVMNXl4LVM4NjV0cHVz
  dTA0bXpzYUJRZ21od1ZFVXBRdWNrcG1YWkNLNHlJUXktaHNFQUlJSmVxdFB3dVAySXF0X2
  I5dlk0bzExeXdzeXhzdmp2RnNKN0VVZU1MaGE2R2dSanBSbnU5RWIzRnlJZ0U5M0VVNEEw
  T0lUMWlOSGNRYWc0eWtOc3dPdkxQbjZIZ21zQ05ESlgwekc2RlFDMTZRdjBSQ25SVTdfV2
  VvblhSTUZwUzZRZ1JiSk45R1NMckN5bklJSWxUcDBxNHBaS05zM0tqQ2tMUzJrb3Bhd2Y0
  WF9BUllmTko3a0s5eW5BR0dCcktnUWJNRWVxUEFmMDBKMlYtVXpuU1JMZmQ4SGs3Y2JEdk
  5RQlhHQW9BR0ViaGRwVUc0RXFwMlVyQko3dEtyUUVSRlh4RTVsOFNHY2czQ1RmN2Zoazdx
  VEFBVjVsWEFnOUtOUDF1c1ZRZk1fUlBleHFNTG9WQVVKV2syQkF6WF9uSEhkVVhaSVBIOG
  hLeDctdEFRV0dTWUd0R2FmanZJZzI2c082TzloQWZVd3BpSV90MzF6SkZORDU0OTZURHBz
  QmNnd2dMLU1UcVhCRUJ2NEhvQld5SG1DVjVFMUwiLCJ0YWciOiJkbXlEeWZJVlNJUi1Ren
  ExOEgybFRIeEMxbl9HZEtrdnZNMDJUcHdsYzQwIn19fQ",
  "protected":"e-KAnGFsZ-KAnTrigJxSUzI1NuKAnX0",    //RSAwithSHA256
  "header": {
    "kid":"e9bc097a-ce51-4036-9562-d2ade882db0d",             
      "signer":"
      MIIC3zCCAkigAwIBAgIJAJf2fFkE1BYOMA0GCSqGSIb3DQEBBQUAMFoxCzAJBgNVBA
      YTAlVTMRMwEQYDVQQIDApDYWxpZm9ybmlhMRMwEQYDVQQHDApDYWxpZm9ybmlhMSEw
      HwYDVQQKDBhJbnRlcm5ldCBXaWRnaXRzIFB0eSBMdGQwHhcNMTUwNzAyMDkwMTE4Wh
      cNMjAwNjMwMDkwMTE4WjBaMQswCQYDVQQGEwJVUzETMBEGA1UECAwKQ2FsaWZvcm5p
      YTETMBEGA1UEBwwKQ2FsaWZvcm5pYTEhMB8GA1UECgwYSW50ZXJuZXQgV2lkZ2l0cy
      BQdHkgTHRkMIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC8ZtxM1bYickpgSVG-
      meHInI3f_chlMBdL8l7daOEztSs_a6GLqmvSu-
      AoDpTsfEd4EazdMBp5fmgLRGdCYMcI6bgpO94h5CCnlj8xFKPq7qGixdwGUA6b_ZI3
      c4cZ8eu73VMNrrn_z3WTZlExlpT9XVj-
      ivhfJ4a6T20EtMM5qwIDAQABo4GsMIGpMHQGA1UdIwRtMGuhXqRcMFoxCzAJBgNVBA
      YTAlVTMRMwEQYDVQQIDApDYWxpZm9ybmlhMRMwEQYDVQQHDApDYWxpZm9ybmlhMSEw
      HwYDVQQKDBhJbnRlcm5ldCBXaWRnaXRzIFB0eSBMdGSCCQCX9nxZBNQWDjAJBgNVHR
      MEAjAAMA4GA1UdDwEB_wQEAwIGwDAWBgNVHSUBAf8EDDAKBggrBgEFBQcDAzANBgkq
      hkiG9w0BAQUFAAOBgQAGkz9QpoxghZUWT4ivem4cIckfxzTBBiPHCjrrjB2X8Ktn8G
      SZ1MdyIZV8fwdEmD90IvtMHgtzK-
      9wo6Aibj_rVIpxGb7trP82uzc2X8VwYnQbuqQyzofQvcwZHLYplvi95pZ5fVrJvnYA
      UBFyfrdT5GjqL1nqH3a_Y3QPscuCjg"
        },
     "signature":"nuQUsCTEBLeaRzuwd7q1iPIYEJ2eJfurO5sT5Y-
     N03zFRcv1jvrqMHtx_pw0Y9YWjmpoWfpfelhwGEko9SgeeBnznmkZbp7kjS6MmX4CKz
     9OApe3-VI7yL9Yp0WNdRh3425eYfuapCy3lcXFln5JBAUnU_OzUg3RWxcU_yGnFsw"
  }
}
             

A.1.2.2. Sample CreateSDResponse

{
  "CreateSDTBSResponse": {
    "ver":"1.0",
    "status":"pass",
    "rid":"req-01",
    "tid":"tran-01",
    "content":{
      "did":"zAHkb0-SQh9U_OT8mR5dB-tygcqpUJ9_x07pIiw8WoM",
      "sdname":"sd.bank.com",
      "teespaik":"AQABjY9KiwH3hkMmSAAN6CLXot525U85WNlWKAQz5TOdfe_CM8h-
      X6_EHX1gOXoyRXaBiKMqWb0YZLCABTw1ytdXy2kWa525imRho8Vqn6HDGsJDZPDru9
      GnZR8pZX5ge_dWXB_uljMvDttc5iAWEJ8ZgcpLGtBTGLZnQoQbjtn1lIE",
    }
  }
}
             

Here is the response message after the content is encrypted and encoded.

{
  "CreateSDResponse": {
    "payload":"
    eyJDcmVhdGVTRFRCU1Jlc3BvbnNlIjp7InZlciI6IjEuMCIsInN0YXR1cyI6InBhc3Mi
    LCJyaWQiOiJyZXEtMDEiLCJ0aWQiOiJ0cmFuLTAxIiwiY29udGVudCI6eyJwcm90ZWN0
    ZWQiOiJlLUtBbkdWdVktS0FuVHJpZ0p4Qk1USTRRMEpETFVoVE1qVTI0b0NkZlEiLCJy
    ZWNpcGllbnRzIjpbeyJoZWFkZXIiOnsiYWxnIjoiUlNBMV81In0sImVuY3J5cHRlZF9r
    ZXkiOiJOX0I4R3pldUlfN2hwd0wwTFpHSTkxVWVBbmxJRkJfcndmZU1yZERrWnFGak1s
    VVhjdlI0XzhhOGhyeFI4SXR3aEtFZnVfRWVLRDBQb0dqQ2pCSHcxdG1ULUN6eWhsbW5v
    Slk3LXllWnZzRkRpc2VNTkd0eGE0OGZJYUs2VWx5NUZMYXBCZVc5T1I5bmktOU9GQV9j
    aFVuWWl3b2Q4ZTJFa0Vpd0JEZ1EzMk0ifV0sIml2IjoiQXhZOERDdERhR2xzYkdsamIz
    Um9aUSIsImNpcGhlcnRleHQiOiJsalh6Wk5JTmR1WjFaMXJHVElkTjBiVUp1RDRVV2xT
    QVptLWd6YnJINFVDYy1jMEFQenMtMWdWSFk4NTRUR3VMYkdyRmVHcDFqM2Fsb1lacWZp
    ZnE4aEt3Ty16RFlBN2tmVFhBZHp6czM4em9xeG4zbHoyM2w1RUlGUWhrOHBRWTRYTHRW
    M3ZBQWlNYnlrQ1Q3VS1CWDdWcjBacVNhYWZTQVZ4OFBLQ1RIU3hHN3hHVko0NkxxRzJS
    RE54WXQ4RC1SQ3lZUi1zRTM0MUFKZldEc2FLaGRRbzJXcjNVN1hTOWFqaXJtWjdqTlJ4
    cVRodHJBRWlIY1ctOEJMdVFHWEZ1YUhLMTZrenJKUGl4d0VXbzJ4cmw4cmkwc3ZRcHpl
    Z2M3MEt2Z0I0NUVaNHZiNXR0YlUya25hN185QU1Wcm4wLUJaQ1Bnb280MWlFblhuNVJn
    TXY2c2V2Y1JPQ2xHMnpWSjFoRkVLYjk2akEiLCJ0YWciOiIzOTZISTk4Uk1NQnR0eDlo
    ZUtsODROaVZLd0lJSzI0UEt2Z1RGYzFrbEJzIn19fQ",
    "protected": "e-KAnGFsZ-KAnTrigJxSUzI1NuKAnX0",
    "header": {
        "kid":"e9bc097a-ce51-4036-9562-d2ade882db0d",
        "signer":"
            MIIC3zCCAkigAwIBAgIJAJf2fFkE1BYOMA0GCSqGSIb3DQEBBQUAMFoxCzAJ
            BgNVBAYTAlVTMRMwEQYDVQQIDApDYWxpZm9ybmlhMRMwEQYDVQQHDApDYWxp
            Zm9ybmlhMSEwHwYDVQQKDBhJbnRlcm5ldCBXaWRnaXRzIFB0eSBMdGQwHhcN
            MTUwNzAyMDkwMTE4WhcNMjAwNjMwMDkwMTE4WjBaMQswCQYDVQQGEwJVUzET
            MBEGA1UECAwKQ2FsaWZvcm5pYTETMBEGA1UEBwwKQ2FsaWZvcm5pYTEhMB8G
            A1UECgwYSW50ZXJuZXQgV2lkZ2l0cyBQdHkgTHRkMIGfMA0GCSqGSIb3DQEB
            AQUAA4GNADCBiQKBgQC8ZtxM1bYickpgSVG-
            meHInI3f_chlMBdL8l7daOEztSs_a6GLqmvSu-
            AoDpTsfEd4EazdMBp5fmgLRGdCYMcI6bgpO94h5CCnlj8xFKPq7qGixdwGUA
            6b_ZI3c4cZ8eu73VMNrrn_z3WTZlExlpT9XVj-
            ivhfJ4a6T20EtMM5qwIDAQABo4GsMIGpMHQGA1UdIwRtMGuhXqRcMFoxCzAJ
            BgNVBAYTAlVTMRMwEQYDVQQIDApDYWxpZm9ybmlhMRMwEQYDVQQHDApDYWxp
            Zm9ybmlhMSEwHwYDVQQKDBhJbnRlcm5ldCBXaWRnaXRzIFB0eSBMdGSCCQCX
            9nxZBNQWDjAJBgNVHRMEAjAAMA4GA1UdDwEB_wQEAwIGwDAWBgNVHSUBAf8E
            DDAKBggrBgEFBQcDAzANBgkqhkiG9w0BAQUFAAOBgQAGkz9QpoxghZUWT4iv
            em4cIckfxzTBBiPHCjrrjB2X8Ktn8GSZ1MdyIZV8fwdEmD90IvtMHgtzK-
            9wo6Aibj_rVIpxGb7trP82uzc2X8VwYnQbuqQyzofQvcwZHLYplvi95pZ5fV
            rJvnYAUBFyfrdT5GjqL1nqH3a_Y3QPscuCjg"
    },
    "signature":"jnJtaB0vFFwrE-qKOR3Pu9pf2gNoI1s67GgPCTq0U-
    qrz97svKpuh32WgCP2MWCoQPEswsEX-nxhIx_siTe4zIPO1nBYn-
    R7b25rQaF87O8uAOOnBN5Yl2Jk3laIbs-
    hGE32aRZDhrVoyEdSvIFrT6AQqD20bIAZGqTR-zA-900"
  }
}
             

A.1.3. Sample UpdateSD

A.1.3.1. Sample UpdateSDRequest


{
  "UpdateSDTBSRequest": {
    "ver": "1.0",
    "rid": "1222DA7D-8993-41A4-AC02-8A2807B31A3A",
    "tid": "4F454A7F-002D-4157-884E-B0DD1A06A8AE",
    "tee": "Primary TEE ABC",
    "nextdsi": "false",
    "dsihash":
    "
    IsOvwpzDk8Onw4bCrsKTJsONwrbDrcKJYjVTw4vCu8OAw4JEw6zCgsK8w4JCacKxW8Kf
    w5o7",
    "content": { // NEEDS to BE ENCRYPTED
      "tsmid": "id1.tsmxyz.com",
      "spid": "com.acmebank.spid1",
      "sdname": "com.acmebank.sdname1",
      "changes": {
        "newsdname": "com.acmebank.sdname2",
        "newspid": "com.acquirer.spid1",
        "spcert":
        "MIIDFjCCAn-
        gAwIBAgIJAIk0Tat0tquDMA0GCSqGSIb3DQEBBQUAMGwxCzAJBgNVBAYTAktSMQ4
        wDAYDVQQIDAVTZW91bDESMBAGA1UEBwwJR3Vyby1kb25nMRAwDgYDVQQKDAdTb2x
        hY2lhMRAwDgYDVQQLDAdTb2xhY2lhMRUwEwYDVQQDDAxTb2xhLWNpYS5jb20wHhc
        NMTUwNzAyMDg1MTU3WhcNMjAwNjMwMDg1MTU3WjBsMQswCQYDVQQGEwJLUjEOMAw
        GA1UECAwFU2VvdWwxEjAQBgNVBAcMCUd1cm8tZG9uZzEQMA4GA1UECgwHU29sYWN
        pYTEQMA4GA1UECwwHU29sYWNpYTEVMBMGA1UEAwwMU29sYS1jaWEuY29tMIGfMA0
        GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDYWLrFf2OFMEciwSYsyhaLY4kslaWcXA0
        hCWJRaFzt5mU-
        lpSJ4jeu92inBbsXcI8PfRbaItsgW1TD1Wg4gQH4MX_YtaBoOepE--
        3JoZZyPyCWS3AaLYWrDmqFXdbzaO1i8GxB7zz0gWw55bZ9jyzcl5gQzWSqMRpx_d
        cad2SP2wIDAQABo4G_MIG8MIGGBgNVHSMEfzB9oXCkbjBsMQswCQYDVQQGEwJLUj
        EOMAwGA1UECAwFU2VvdWwxEjAQBgNVBAcMCUd1cm8tZG9uZzEQMA4GA1UECgwHU2
        9sYWNpYTEQMA4GA1UECwwHU29sYWNpYTEVMBMGA1UEAwwMU29sYS1jaWEuY29tgg
        kAiTRNq3S2q4MwCQYDVR0TBAIwADAOBgNVHQ8BAf8EBAMCBsAwFgYDVR0lAQH_BA
        wwCgYIKwYBBQUHAwMwDQYJKoZIhvcNAQEFBQADgYEAEFMhRwEQ-
        LDa9O7P1N0mcLORpo6fW3QuJfuXbRQRQGoXddXMKazI4VjbGaXhey7Bzvk6TZYDa
        -
        GRiZby1J47UPaDQR3UiDzVvXwCOU6S5yUhNJsW_BeMViYj4lssX28iPpNwLUCVm1
        QVTHILI6afLCRWXXclc1L5KGY290OwIdQ",
        "renewteespaik": "0"
      }
    }
  }
}
             

A.1.3.2. Sample UpdateSDResponse

{
  "UpdateSDTBSResponse": {
    "ver": "1.0",
    "status": "pass",
    "rid": "1222DA7D-8993-41A4-AC02-8A2807B31A3A",
    "tid": "4F454A7F-002D-4157-884E-B0DD1A06A8AE",
    "content": {
      "did": "MTZENTE5Qzc0Qzk0NkUxMzYxNzk0NjY4NTc3OTY4NTI=",
      "teespaik":
      "AQABjY9KiwH3hkMmSAAN6CLXot525U85WNlWKAQz5TOdfe_CM8h-
      X6_EHX1gOXoyRXaBiKMqWb0YZLCABTw1ytdXy2kWa525imRho8Vqn6HDGsJDZPDru9
      GnZR8pZX5ge_dWXB_uljMvDttc5iAWEJ8ZgcpLGtBTGLZnQoQbjtn1lIE",
      "teespaiktype": "RSA"
    }
  }
}
             

A.1.4. Sample DeleteSD

A.1.4.1. Sample DeleteSDRequest

TSM builds message - including data to be encrypted.

{
     "DeleteSDTBSRequest": {
       "ver": "1.0",
       "rid": "{712551F5-DFB3-43f0-9A63-663440B91D49}",
       "tid": "{4F454A7F-002D-4157-884E-B0DD1A06A8AE}",
       "tee": "Primary TEE",
       "nextdsi": "false",
       "dsihash": "AAECAwQFBgcICQoLDA0ODwABAgMEBQYHCAkKCwwNDg8=",
       "content": ENCRYPTED {
         "tsmid": "tsm1.com",
         "sdname": "default.acmebank.com",
         "deleteta": "1"
       }
     }
   }
             

TSM encrypts the "content".

{
  "DeleteSDTBSRequest": {
    "ver": "1.0",
    "rid": "{712551F5-DFB3-43f0-9A63-663440B91D49}",
    "tid": "{4F454A7F-002D-4157-884E-B0DD1A06A8AE}",
    "tee": "Primary TEE",
    "nextdsi": "false",
    "dsihash": "AAECAwQFBgcICQoLDA0ODwABAgMEBQYHCAkKCwwNDg8=",
    "content": {
    "protected": "eyJlbmMiOiJBMTI4Q0JDLUhTMjU2In0",
    "recipients": [
      {
        "header": {
          "alg": "RSA1_5"
        },
      "encrypted_key":
      "
      QUVTMTI4IChDRUspIGtleSwgZW5jcnlwdGVkIHdpdGggVFNNIFJTQSBwdWJsaWMga2
      V5LCB1c2luZyBSU0ExXzUgcGFkZGluZw"
      }
    ],
    "iv": "rWO5DVmQX9ogelMLBIogIA",
    "ciphertext":
    "
    c2FtcGxlIGRzaSBkYXRhIGVuY3J5cHRlZCB3aXRoIEFFUzEyOCBrZXkgZnJvbSByZWNp
    cGllbnRzLmVuY3J5cHRlZF9rZXk",
    "tag": "c2FtcGxlIGF1dGhlbnRpY2F0aW9uIHRhZw"
    }
  }
}
             

TSM signs "DeleteSDTBSRequest" to form "DeleteSDRequest"

{
  "DeleteSDRequest": {
    "payload":"
    ewoJIkRlbGV0ZVNEVEJTUmVxdWVzdCI6IHsKCQkidmVyIjogIjEuMCIsCgkJInJp
    ZCI6ICJ7NzEyNTUxRjUtREZCMy00M2YwLTlBNjMtNjYzNDQwQjkxRDQ5fSIsCgkJ
    InRpZCI6ICJ7NEY0NTRBN0YtMDAyRC00MTU3LTg4NEUtQjBERDFBMDZBOEFFfSIs
    CgkJInRlZSI6ICJQcmltYXJ5IFRFRSIsCgkJIm5leHRkc2kiOiAiZmFsc2UiLAoJ
    CSJkc2loYXNoIjogIkFBRUNBd1FGQmdjSUNRb0xEQTBPRHdBQkFnTUVCUVlIQ0Fr
    S0N3d05EZzg9IiwKCQkiY29udGVudCI6IHsKCQkJInByb3RlY3RlZCI6ICJleUps
    Ym1NaU9pSkJNVEk0UTBKRExVaFRNalUySW4wIiwKCQkJInJlY2lwaWVudHMiOiBb
    ewoJCQkJImhlYWRlciI6IHsKCQkJCQkiYWxnIjogIlJTQTFfNSIKCQkJCX0sCgkJ
    CQkiZW5jcnlwdGVkX2tleSI6ICJRVVZUTVRJNElDaERSVXNwSUd0bGVTd2daVzVq
    Y25sd2RHVmtJSGRwZEdnZ1ZGTk5JRkpUUVNCd2RXSnNhV01nYTJWNUxDQjFjMmx1
    WnlCU1UwRXhYelVnY0dGa1pHbHVadyIKCQkJfV0sCgkJCSJpdiI6ICJyV081RFZt
    UVg5b2dlbE1MQklvZ0lBIiwKCQkJImNpcGhlcnRleHQiOiAiYzJGdGNHeGxJR1J6
    YVNCa1lYUmhJR1Z1WTNKNWNIUmxaQ0IzYVhSb0lFRkZVekV5T0NCclpYa2dabkp2
    YlNCeVpXTnBjR2xsYm5SekxtVnVZM0o1Y0hSbFpGOXJaWGsiLAoJCQkidGFnIjog
    ImMyRnRjR3hsSUdGMWRHaGxiblJwWTJGMGFXOXVJSFJoWnciCgkJfQoJfQp9",
    "protected":"eyJhbGciOiJSUzI1NiJ9",
    "header": {
      "x5c": ["ZXhhbXBsZSBBU04xIHNpZ25lciBjZXJ0aWZpY2F0ZQ==",
              "ZXhhbXBsZSBBU04xIENBIGNlcnRpZmljYXRl"]
    },
    "signature":"c2FtcGxlIHNpZ25hdHVyZQ"
  }
}
             

A.1.4.2. Sample DeleteSDResponse

TEE creates "DeleteSDTBSResponse" to respond to the "DeleteSDRequest" message from the TSM, including data to be encrypted.

  {
     "DeleteSDTBSResponse": {
       "ver": "1.0",
       "status": "pass",
       "rid": "{712551F5-DFB3-43f0-9A63-663440B91D49}",
       "tid": "{4F454A7F-002D-4157-884E-B0DD1A06A8AE}",
       "content": ENCRYPTED {
         "did": "MTZENTE5Qzc0Qzk0NkUxMzYxNzk0NjY4NTc3OTY4NTI=",
       }
     }
   }
             

TEE encrypts the "content" for the TSM.

   {
    "DeleteSDTBSResponse": {
     "ver": "1.0",
     "status": "pass",
     "rid": "{712551F5-DFB3-43f0-9A63-663440B91D49}",
     "tid": "{4F454A7F-002D-4157-884E-B0DD1A06A8AE}",
      "content": {
      "protected": "eyJlbmMiOiJBMTI4Q0JDLUhTMjU2In0K",
      "recipients": [
        {
          "header": {
          "alg": "RSA1_5"
        },
        "encrypted_key":
        "
        QUVTMTI4IChDRUspIGtleSwgZW5jcnlwdGVkIHdpdGggVFNNIFJTQSBwdWJsaWMg
        a2V5LCB1c2luZyBSU0ExXzUgcGFkZGluZw"
        }
      ],
      "iv": "ySGmfZ69YlcEilNr5_SGbA",
      "ciphertext":
      "
      c2FtcGxlIGRzaSBkYXRhIGVuY3J5cHRlZCB3aXRoIEFFUzEyOCBrZXkgZnJvbSByZW
      NpcGllbnRzLmVuY3J5cHRlZF9rZXk",
      "tag": "c2FtcGxlIGF1dGhlbnRpY2F0aW9uIHRhZw"
      }
     }
   }
             

TEE signs "DeleteSDTBSResponse" to form "DeleteSDResponse"

{
  "DeleteSDResponse": {
    "payload":"
    ewoJIkRlbGV0ZVNEVEJTUmVzcG9uc2UiOiB7CgkJInZlciI6ICIxLjAiLAoJCSJz
    dGF0dXMiOiAicGFzcyIsCgkJInJpZCI6ICJ7NzEyNTUxRjUtREZCMy00M2YwLTlB
    NjMtNjYzNDQwQjkxRDQ5fSIsCgkJInRpZCI6ICJ7NEY0NTRBN0YtMDAyRC00MTU3
    LTg4NEUtQjBERDFBMDZBOEFFfSIsCgkJImNvbnRlbnQiOiB7CgkJCSJwcm90ZWN0
    ZWQiOiAiZXlKbGJtTWlPaUpCTVRJNFEwSkRMVWhUTWpVMkluMEsiLAoJCQkicmVj
    aXBpZW50cyI6IFt7CgkJCQkiaGVhZGVyIjogewoJCQkJCSJhbGciOiAiUlNBMV81
    IgoJCQkJfSwKCQkJCSJlbmNyeXB0ZWRfa2V5IjogIlFVVlRNVEk0SUNoRFJVc3BJ
    R3RsZVN3Z1pXNWpjbmx3ZEdWa0lIZHBkR2dnVkZOTklGSlRRU0J3ZFdKc2FXTWdh
    MlY1TENCMWMybHVaeUJTVTBFeFh6VWdjR0ZrWkdsdVp3IgoJCQl9XSwKCQkJIml2
    IjogInlTR21mWjY5WWxjRWlsTnI1X1NHYkEiLAoJCQkiY2lwaGVydGV4dCI6ICJj
    MkZ0Y0d4bElHUnphU0JrWVhSaElHVnVZM0o1Y0hSbFpDQjNhWFJvSUVGRlV6RXlP
    Q0JyWlhrZ1puSnZiU0J5WldOcGNHbGxiblJ6TG1WdVkzSjVjSFJsWkY5clpYayIs
    CgkJCSJ0YWciOiAiYzJGdGNHeGxJR0YxZEdobGJuUnBZMkYwYVc5dUlIUmhadyIK
    CQl9Cgl9Cn0",
    "protected":"eyJhbGciOiJSUzI1NiJ9",
    "signature":"c2FtcGxlIHNpZ25hdHVyZQ"
  }
}
             

TEE returns "DeleteSDResponse" back to OTrP Agent, which returns message back to TSM.

A.2. Sample TA Management Messages

A.2.1. Sample InstallTA

A.2.1.1. Sample InstallTARequest

{
  "InstallTATBSRequest": {
    "ver": "1.0",
    "rid": "24BEB059-0AED-42A6-A381-817DFB7A1207",
    "tid": "4F454A7F-002D-4157-884E-B0DD1A06A8AE",
    "tee": "Primary TEE ABC",
    "nextdsi": "true",
    "dsihash":
    "
    IsOvwpzDk8Onw4bCrsKTJsONwrbDrcKJYjVTw4vCu8OAw4JEw6zCgsK8w4JCacKxW8Kf
    w5o7",
    "content": {
      "tsmid": "id1.tsmxyz.com",
      "spid": "com.acmebank.spid1",
      "sdname": "com.acmebank.sdname1",
      "taid": "com.acmebank.taid.banking"
    },
    "encrypted_ta": {
      "key":
      "mLBjodcE4j36y64nC/nEs694P3XrLAOokjisXIGfs0H7lOEmT5FtaNDYEMcg9RnE
      ftlJGHO7N0lgcNcjoXBmeuY9VI8xzrsZM9gzH6VBKtVONSx0aw5IAFkNcyPZwDdZ
      MLwhvrzPJ9Fg+bZtrCoJz18PUz+5aNl/dj8+NM85LCXXcBlZF74btJer1Mw6ffzT
      /grPiEQTeJ1nEm9F3tyRsvcTInsnPJ3dEXv7sJXMrhRKAeZsqKzGX4eiZ3rEY+FQ
      6nXULC8cAj5XTKpQ/EkZ/iGgS0zcXR7KUJv3wFEmtBtPD/+ze08NILLmxM8olQFj
      //Lq0gGtq8vPC8r0oOfmbQ==",
      "iv": "4F5472504973426F726E496E32303135",
      "alg": "AESCBC",
      "ciphertadata":
      "......0x/5KGCXWfg1Vrjm7zPVZqtYZ2EovBow+7EmfOJ1tbk......=",
      "cipherpdata": "0x/5KGCXWfg1Vrjm7zPVZqtYZ2EovBow+7EmfOJ1tbk="
    }
  }
}
             

A.2.1.2. Sample InstallTAResponse

A sample to-be-signed response of InstallTA looks as follows.

{
  "InstallTATBSResponse": {
    "ver": "1.0",
    "status": "pass",
    "rid": "24BEB059-0AED-42A6-A381-817DFB7A1207",
    "tid": "4F454A7F-002D-4157-884E-B0DD1A06A8AE",
    "content": {
      "did": "MTZENTE5Qzc0Qzk0NkUxMzYxNzk0NjY4NTc3OTY4NTI=",
      "dsi": {
        "tfwdata": {
          "tbs": "ezRGNDU0QTdGLTAwMkQtNDE1Ny04ODRFLUIwREQxQTA2QThBRX0="
          "cert": "ZXhhbXBsZSBGVyBjZXJ0aWZpY2F0ZQ==", 
          "sigalg": "UlMyNTY=",
          "sig": "c2FtcGxlIEZXIHNpZ25hdHVyZQ=="
        },
        "tee": {
          "name": "Primary TEE",
          "ver": "1.0",
          "cert": "c2FtcGxlIFRFRSBjZXJ0aWZpY2F0ZQ==",
          "cacert": [ 
            "c2FtcGxlIENBIGNlcnRpZmljYXRlIDE=", 
            "c2FtcGxlIENBIGNlcnRpZmljYXRlIDI="
          ],
          "sdlist": {
            "cnt": "1",
            "sd": [
              {
                "name": "com.acmebank.sdname1",
                "spid": "com.acmebank.spid1",
                "talist": [
                    {
                    "taid": "com.acmebank.taid.banking",
                    "taname": "Acme secure banking app"
                    },
                    {
                    "taid": "acom.acmebank.taid.loyalty.rewards",
                    "taname": "Acme loyalty rewards app"
                    }
                ]
              }
            ]
          },
          "teeaiklist": [
            {
              "spaik":
                "c2FtcGxlIEFTTjEgZW5jb2RlZCBQS0NTMSBwdWJsaWNrZXk=",
              "spaiktype": "RSA"
              "spid": "acmebank.com"
            }
          ]
        }
      }
    }
  }
}
             

A.2.2. Sample UpdateTA

A.2.2.1. Sample UpdateTARequest

{
  "UpdateTATBSRequest": {
    "ver": "1.0",
    "rid": "req-2",
    "tid": "tran-01",
    "tee": "SecuriTEE",
                "nextdsi": " false",
    "dsihash": "gwjul_9MZks3pqUSN1-eL1aViwGXNAxk0AIKW79dn4U",
    "content": { 
      "tsmid": "tsm1.acme.com",
      "spid": "bank.com",
      "sdname": "sd.bank.com",          
      "taid": "sd.bank.com.ta"
    },
    "encrypted_ta": {
      "key":
      "
      XzmAn_RDVk3IozMwNWhiB6fmZlIs1YUvMKlQAv_UDoZ1fvGGsRGo9bT0A440aYMgLt
      GilKypoJjCgijdaHgamaJgRSc4Je2otpnEEagsahvDNoarMCC5nGQdkRxW7Vo2NKgL
      A892HGeHkJVshYm1cUlFQ-BhiJ4NAykFwlqC_oc",
      "iv": "AxY8DCtDaGlsbGljb3RoZQ",
      "alg": "AESCBC",
      "ciphernewtadata":
      "KHqOxGn7ib1F_14PG4_UX9DBjOcWkiAZhVE-U-
      67NsKryHGokeWr2spRWfdU2KWaaNncHoYGwEtbCH7XyNbOFh28nzwUmstep4nHWbAl
      XZYTNkENcABPpuw_G3I3HADo"
    }
  }
}
             
{
  "UpdateTARequest": {
    "payload" :
    "
    eyJVcGRhdGVUQVRCU1JlcXVlc3QiOnsidmVyIjoiMS4wIiwicmlkIjoicmVxLTIiLCJ0
    aWQiOiJ0cmFuLTAxIiwidGVlIjoiU2VjdXJpVEVFIiwibmV4dGRzaSI6ImZhbHNlIiwi
    ZHNpaGFzaCI6Imd3anVsXzlNWmtzM3BxVVNOMS1lTDFhVml3R1hOQXhrMEFJS1c3OWRu
    NFUiLCJjb250ZW50Ijp7InByb3RlY3RlZCI6ImV5SmxibU1pT2lKQk1USTRRMEpETFVo
    VE1qVTJJbjAiLCJyZWNpcGllbnRzIjpbeyJoZWFkZXIiOnsiYWxnIjoiUlNBMV81In0s
    ImVuY3J5cHRlZF9rZXkiOiJYem1Bbl9SRFZrM0lvek13TldoaUI2Zm1abElzMVlVdk1L
    bFFBdl9VRG9aMWZ2R0dzUkdvOWJUMEE0NDBhWU1nTHRHaWxLeXBvSmpDZ2lqZGFIZ2Ft
    YUpnUlNjNEplMm90cG5FRWFnc2FodkROb2FyTUNDNW5HUWRrUnhXN1ZvMk5LZ0xBODky
    SEdlSGtKVnNoWW0xY1VsRlEtQmhpSjROQXlrRndscUNfb2MifV0sIml2IjoiQXhZOERD
    dERhR2xzYkdsamIzUm9aUSIsImNpcGhlcnRleHQiOiJIYTcwVXRZVEtWQmtXRFJuMi0w
    SF9IdkZtazl5SGtoVV91bk1OLWc1T3BqLWF1NGFUb2lxWklMYzVzYTdENnZZSjF6eW04
    QW1JOEJIVXFqc2l5Z0tOcC1HdURJUjFzRXc0a2NhMVQ5ZENuU0RydHhSUFhESVdrZmt3
    azZlR1NQWiIsInRhZyI6Im9UN01UTE41eWtBTFBoTDR0aUh6T1pPTGVFeU9xZ0NWaEM5
    MXpkcldMU0UifSwiZW5jcnlwdGVkX3RhIjp7ImtleSI6Ilh6bUFuX1JEVmszSW96TXdO
    V2hpQjZmbVpsSXMxWVV2TUtsUUF2X1VEb1oxZnZHR3NSR285YlQwQTQ0MGFZTWdMdEdp
    bEt5cG9KakNnaWpkYUhnYW1hSmdSU2M0SmUyb3RwbkVFYWdzYWh2RE5vYXJNQ0M1bkdR
    ZGtSeFc3Vm8yTktnTEE4OTJIR2VIa0pWc2hZbTFjVWxGUS1CaGlKNE5BeWtGd2xxQ19v
    YyIsIml2IjoiQXhZOERDdERhR2xzYkdsamIzUm9aUSIsImFsZyI6IkFFU0NCQyIsImNp
    cGhlcm5ld3RhZGF0YSI6IktIcU94R243aWIxRl8xNFBHNF9VWDlEQmpPY1draUFaaFZF
    LVUtNjdOc0tyeUhHb2tlV3Iyc3BSV2ZkVTJLV2FhTm5jSG9ZR3dFdGJDSDdYeU5iT0Zo
    MjhuendVbXN0ZXA0bkhXYkFsWFpZVE5rRU5jQUJQcHV3X0czSTNIQURvIn19fQ",
    "protected": " eyJhbGciOiJSUzI1NiJ9",
    "header": {
      "kid":"e9bc097a-ce51-4036-9562-d2ade882db0d",
      "signer":"
      MIIC3zCCAkigAwIBAgIJAJf2fFkE1BYOMA0GCSqGSIb3DQEBBQUAMFoxCzAJBgNVBA
      YTAlVTMRMwEQYDVQQIDApDYWxpZm9ybmlhMRMwEQYDVQQHDApDYWxpZm9ybmlhMSEw
      HwYDVQQKDBhJbnRlcm5ldCBXaWRnaXRzIFB0eSBMdGQwHhcNMTUwNzAyMDkwMTE4Wh
      cNMjAwNjMwMDkwMTE4WjBaMQswCQYDVQQGEwJVUzETMBEGA1UECAwKQ2FsaWZvcm5p
      YTETMBEGA1UEBwwKQ2FsaWZvcm5pYTEhMB8GA1UECgwYSW50ZXJuZXQgV2lkZ2l0cy
      BQdHkgTHRkMIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC8ZtxM1bYickpgSVG-
      meHInI3f_chlMBdL8l7daOEztSs_a6GLqmvSu-
      AoDpTsfEd4EazdMBp5fmgLRGdCYMcI6bgpO94h5CCnlj8xFKPq7qGixdwGUA6b_ZI3
      c4cZ8eu73VMNrrn_z3WTZlExlpT9XVj-
      ivhfJ4a6T20EtMM5qwIDAQABo4GsMIGpMHQGA1UdIwRtMGuhXqRcMFoxCzAJBgNVBA
      YTAlVTMRMwEQYDVQQIDApDYWxpZm9ybmlhMRMwEQYDVQQHDApDYWxpZm9ybmlhMSEw
      HwYDVQQKDBhJbnRlcm5ldCBXaWRnaXRzIFB0eSBMdGSCCQCX9nxZBNQWDjAJBgNVHR
      MEAjAAMA4GA1UdDwEB_wQEAwIGwDAWBgNVHSUBAf8EDDAKBggrBgEFBQcDAzANBgkq
      hkiG9w0BAQUFAAOBgQAGkz9QpoxghZUWT4ivem4cIckfxzTBBiPHCjrrjB2X8Ktn8G
      SZ1MdyIZV8fwdEmD90IvtMHgtzK-
      9wo6Aibj_rVIpxGb7trP82uzc2X8VwYnQbuqQyzofQvcwZHLYplvi95pZ5fVrJvnYA
      UBFyfrdT5GjqL1nqH3a_Y3QPscuCjg"
    },
    "signature":"inB1K6G3EAhF-
    FbID83UI25R5Ao8MI4qfrbrmf0UQhjM3O7_g3l6XxN_JkHrGQaZr-
    myOkGPVM8BzbUZW5GqxNZwFXwMeaoCjDKc4Apv4WZkD1qKJxkg1k5jaUCfJz1Jmw_XtX
    6MHhrLh9ov03S9PtuT1VAQ0FVUB3qFIvjSnNU"
  }
}
             

A.2.2.2. Sample UpdateTAResponse

{
  "UpdateTATBSResponse": {
    "ver": "1.0",
    "status": "pass",
        "rid": "req-2",
        "tid": "tran-01",
        "content": {
      "did": "zAHkb0-SQh9U_OT8mR5dB-tygcqpUJ9_x07pIiw8WoM"
    }
  }
}
             
{
  "UpdateTAResponse":{
    "payload":"
    eyJVcGRhdGVUQVRCU1Jlc3BvbnNlIjp7InZlciI6IjEuMCIsInN0YXR1cyI6InBhc3Mi
    LCJyaWQiOiJyZXEtMiIsInRpZCI6InRyYW4tMDEiLCJjb250ZW50Ijp7InByb3RlY3Rl
    ZCI6ImV5SmxibU1pT2lKQk1USTRRMEpETFVoVE1qVTJJbjAiLCJyZWNpcGllbnRzIjpb
    eyJoZWFkZXIiOnsiYWxnIjoiUlNBMV81In0sImVuY3J5cHRlZF9rZXkiOiJFaGUxLUJB
    UUdJLTNEMFNHdXFGY01MZDJtd0gxQm1uRndYQWx1M1FxUFVXZ1RRVm55SUowNFc2MnBK
    YWVSREFkeTU0R0FSVjBrVzQ0RGw0MkdUUlhqbE1EZ3BYdXdFLWloc1JVV0tNNldCZ2N3
    VXVGQTRUR3gwU0I1NTZCdl92dnBNaFdfMXh2c2FHdFBaQmwxTnZjbXNibzBhY3FobXlu
    bzBDTmF5SVAtX1UifV0sIml2IjoiQXhZOERDdERhR2xzYkdsamIzUm9aUSIsImNpcGhl
    cnRleHQiOiJwc2o2dGtyaGJXM0lmVElMeE9GMU5HdFUtcTFmeVBidV9KWk9jbklycWIw
    eTNPOHN6OTItaWpWR1ZyRW5WbG1sY1FYeWFNZTNyX1JGdEkwV3B4UmRodyIsInRhZyI6
    Ik0zb2dNNk11MVJYMUMybEZvaG5rTkN5b25qNjd2TDNqd2RrZXhFdUlpaTgifX19",
    "protected":"eyJhbGciOiJSUzI1NiJ9",
    "header": {
      "kid":"e9bc097a-ce51-4036-9562-d2ade882db0d",
      "signer":"
      MIIC3zCCAkigAwIBAgIJAJf2fFkE1BYOMA0GCSqGSIb3DQEBBQUAMFoxCzAJBgNVBA
      YTAlVTMRMwEQYDVQQIDApDYWxpZm9ybmlhMRMwEQYDVQQHDApDYWxpZm9ybmlhMSEw
      HwYDVQQKDBhJbnRlcm5ldCBXaWRnaXRzIFB0eSBMdGQwHhcNMTUwNzAyMDkwMTE4Wh
      cNMjAwNjMwMDkwMTE4WjBaMQswCQYDVQQGEwJVUzETMBEGA1UECAwKQ2FsaWZvcm5p
      YTETMBEGA1UEBwwKQ2FsaWZvcm5pYTEhMB8GA1UECgwYSW50ZXJuZXQgV2lkZ2l0cy
      BQdHkgTHRkMIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC8ZtxM1bYickpgSVG-
      meHInI3f_chlMBdL8l7daOEztSs_a6GLqmvSu-
      AoDpTsfEd4EazdMBp5fmgLRGdCYMcI6bgpO94h5CCnlj8xFKPq7qGixdwGUA6b_ZI3
      c4cZ8eu73VMNrrn_z3WTZlExlpT9XVj-
      ivhfJ4a6T20EtMM5qwIDAQABo4GsMIGpMHQGA1UdIwRtMGuhXqRcMFoxCzAJBgNVBA
      YTAlVTMRMwEQYDVQQIDApDYWxpZm9ybmlhMRMwEQYDVQQHDApDYWxpZm9ybmlhMSEw
      HwYDVQQKDBhJbnRlcm5ldCBXaWRnaXRzIFB0eSBMdGSCCQCX9nxZBNQWDjAJBgNVHR
      MEAjAAMA4GA1UdDwEB_wQEAwIGwDAWBgNVHSUBAf8EDDAKBggrBgEFBQcDAzANBgkq
      hkiG9w0BAQUFAAOBgQAGkz9QpoxghZUWT4ivem4cIckfxzTBBiPHCjrrjB2X8Ktn8G
      SZ1MdyIZV8fwdEmD90IvtMHgtzK-
      9wo6Aibj_rVIpxGb7trP82uzc2X8VwYnQbuqQyzofQvcwZHLYplvi95pZ5fVrJvnYA
      UBFyfrdT5GjqL1nqH3a_Y3QPscuCjg"
    },
    "signature":"
    Twajmt_BBLIMcNrDsjqr8lI7O7lEQxXZNhlUOtFkOMMqf37wOPKtp_99LoS82CVmdpCo
    PLaws8zzh-SNIQ42-
    9GYO8_9BaEGCiCwyl8YgWP9fWNfNv2gR2fl2DK4uknkYu1EMBW4YfP81n_pGpb4Gm-
    nMk14grVZygwAPej3ZZk"
  }
}
             

A.2.3. Sample DeleteTA

A.2.3.1. Sample DeleteTARequest

{
  "DeleteTATBSRequest": {
    "ver": "1.0",
    "rid": "req-2",
    "tid": "tran-01",
    "tee": "SecuriTEE",
    "nextdsi": "false",
    "dsihash": "gwjul_9MZks3pqUSN1-eL1aViwGXNAxk0AIKW79dn4U",
    "content": {
      "tsmid": "tsm1.acme.com",
      "sdname": "sd.bank.com",
      "taid": "sd.bank.com.ta"
    }
  }
}
             
{
  "DeleteTARequest": {
    "payload":
    "
    eyJEZWxldGVUQVRCU1JlcXVlc3QiOnsidmVyIjoiMS4wIiwicmlkIjoicmVxLTIiLCJ0
    aWQiOiJ0cmFuLTAxIiwidGVlIjoiU2VjdXJpVEVFIiwibmV4dGRzaSI6ImZhbHNlIiwi
    ZHNpaGFzaCI6Imd3anVsXzlNWmtzM3BxVVNOMS1lTDFhVml3R1hOQXhrMEFJS1c3OWRu
    NFUiLCJjb250ZW50Ijp7InByb3RlY3RlZCI6eyJlbmMiOiJBMTI4Q0JDLUhTMjU2In0s
    InJlY2lwaWVudHMiOlt7ImhlYWRlciI6eyJhbGciOiJSU0ExXzUifSwiZW5jcnlwdGVk
    X2tleSI6ImtyaGs0d2dpY0RlX3d0VXQyTW4tSUJsdUtvX0JkeXpNY2p1cVlBenBPYnRS
    TG9MZzQ0QkFLN2tRVWE1YTg0TEVJRGEzaHNtWDIxdldNZFJLczN4MTJsOUh5VFdfLUNS
    WmZtcUx2bEh1LV9MSVdvc1ZyRTZVMlJqUnRndllVOWliUkVLczkzRDRHWm4xVHFuZG9n
    d0tXRF9jdG1nWG1sbzZZVXpCWDZhR1dZMCJ9XSwiaXYiOiJBeFk4REN0RGFHbHNiR2xq
    YjNSb1pRIiwiY2lwaGVydGV4dCI6IkhhNzBVdFlUS1ZCa1dEUm4yLTBIX1BGa19yQnpQ
    dGJHdzhSNktlMXotdklNeFBSY0Nxa1puZmwyTjRjUTZPSTZCSHZJUUFoM2Jic0l0dHlR
    bXhDTE5Nbm8wejBrYm9TdkIyVXlxWExpeGVZIiwidGFnIjoidEtUbFRLdlR2LTRtVVlG
    Y1dYWnZMMVlhQnRGNloxVlNxOTMzVmI2UEpmcyJ9fX0",
    "protected" : "eyJhbGciOiJSUzI1NiJ9",
    "header":   {
      "kid":"e9bc097a-ce51-4036-9562-d2ade882db0d",
      "signer":"
      MIIC3zCCAkigAwIBAgIJAJf2fFkE1BYOMA0GCSqGSIb3DQEBBQUAMFoxCzAJBgNVBA
      YTAlVTMRMwEQYDVQQIDApDYWxpZm9ybmlhMRMwEQYDVQQHDApDYWxpZm9ybmlhMSEw
      HwYDVQQKDBhJbnRlcm5ldCBXaWRnaXRzIFB0eSBMdGQwHhcNMTUwNzAyMDkwMTE4Wh
      cNMjAwNjMwMDkwMTE4WjBaMQswCQYDVQQGEwJVUzETMBEGA1UECAwKQ2FsaWZvcm5p
      YTETMBEGA1UEBwwKQ2FsaWZvcm5pYTEhMB8GA1UECgwYSW50ZXJuZXQgV2lkZ2l0cy
      BQdHkgTHRkMIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC8ZtxM1bYickpgSVG-
      meHInI3f_chlMBdL8l7daOEztSs_a6GLqmvSu-
      AoDpTsfEd4EazdMBp5fmgLRGdCYMcI6bgpO94h5CCnlj8xFKPq7qGixdwGUA6b_ZI3
      c4cZ8eu73VMNrrn_z3WTZlExlpT9XVj-
      ivhfJ4a6T20EtMM5qwIDAQABo4GsMIGpMHQGA1UdIwRtMGuhXqRcMFoxCzAJBgNVBA
      YTAlVTMRMwEQYDVQQIDApDYWxpZm9ybmlhMRMwEQYDVQQHDApDYWxpZm9ybmlhMSEw
      HwYDVQQKDBhJbnRlcm5ldCBXaWRnaXRzIFB0eSBMdGSCCQCX9nxZBNQWDjAJBgNVHR
      MEAjAAMA4GA1UdDwEB_wQEAwIGwDAWBgNVHSUBAf8EDDAKBggrBgEFBQcDAzANBgkq
      hkiG9w0BAQUFAAOBgQAGkz9QpoxghZUWT4ivem4cIckfxzTBBiPHCjrrjB2X8Ktn8G
      SZ1MdyIZV8fwdEmD90IvtMHgtzK-
      9wo6Aibj_rVIpxGb7trP82uzc2X8VwYnQbuqQyzofQvcwZHLYplvi95pZ5fVrJvnYA
      UBFyfrdT5GjqL1nqH3a_Y3QPscuCjg"
    },
    "signature" :
    "
    BZS0_Ab6pqvGNXe5lqT4Sc3jakyWQeiK9KlVSnimwWnjCCyMtyB9bwvlbILZba3IJiFe
    _3F9bIQpSytGS0f2TQrPTKC7pSjwDw-3kH7HkHcPPJd-
    PpMMfQvRx7AIV8vBqO9MijIC62iN0V2se5z2v8VFjGSoRGgq225w7FvrnWE"
  }
}
             

A.2.3.2. Sample DeleteTAResponse

{
  "DeleteTATBSResponse": {
    "ver": "1.0",
    "status": "pass",
        "rid": "req-2",
        "tid": "tran-01",
        "content": {
      "did": "zAHkb0-SQh9U_OT8mR5dB-tygcqpUJ9_x07pIiw8WoM"
    }
  }
}             

{
  "DeleteTAResponse":{
    "payload":"
    ew0KCSJEZWxldGVUQVRCU1Jlc3BvbnNlIjogew0KCQkidmVyIjogIjEuMCIsDQoJCSJz
    dGF0dXMiOiAicGFzcyIsDQoJCSJyaWQiOiAicmVxLTIiLA0KCQkidGlkIjogInRyYW4t
    MDEiLA0KCQkiY29udGVudCI6IHsNCgkJCSJwcm90ZWN0ZWQiOnsiZW5jIjoiQTEyOENC
    Qy1IUzI1NiJ9LA0KCQkJInJlY2lwaWVudHMiOlsNCgkJCQl7DQoJCQkJCSJoZWFkZXIi
    OnsiYWxnIjoiUlNBMV81In0sDQoJCQkJCSJlbmNyeXB0ZWRfa2V5IjoiTXdtU1ZHaWU2
    eHpfQmxTaFlmTFRKRHhKT3oyNWhvYy1HZ2NEM2o5OWFyM2E4X2lYY182ZE44bFRTb1dD
    X19wZEFhaEMyWk5SakdIcTBCZ2JDYTRKalk0eXRkMVBVWDB6M1psbXl1YnRXM291eEpY
    el9PMzg1WGM4S3hySndjbElyZGx2WUY2OVZmeERLQkVzUHJCdzlVenVIa1VmSU4xWlFU
    bWZ0QmVaSlJnIg0KCQkJCX0NCgkJCV0sDQoJCQkiaXYiOiJBeFk4REN0RGFHbHNiR2xq
    YjNSb1pRIiwNCgkJCSJjaXBoZXJ0ZXh0IjoiamhQTlV5ZkFTel9rVV9GbEM2LUtCME01
    WDBHNE5MbHc0LWt0bERyajZTWlUteUp6eUFUbC1oY0ZBWWMwLXJMVEF4cF93N1d1WER0
    Y3N3SzJSSzRjcWciLA0KCQkJInRhZyI6IlBBeGo5N25oT29qVTNIREhxSll4MGZMNWpt
    b0xkTlJkTHRtSmIzUTdrYXciDQoJCX0NCgl9DQp9",
    "protected": "eyJhbGciOiJSUzI1NiJ9",
    "header": {
      "kid":"e9bc097a-ce51-4036-9562-d2ade882db0d",
      "signer":"
      MIIC3zCCAkigAwIBAgIJAJf2fFkE1BYOMA0GCSqGSIb3DQEBBQUAMFoxCzAJ
      BgNVBAYTAlVTMRMwEQYDVQQIDApDYWxpZm9ybmlhMRMwEQYDVQQHDApDYWxp
      Zm9ybmlhMSEwHwYDVQQKDBhJbnRlcm5ldCBXaWRnaXRzIFB0eSBMdGQwHhcN
      MTUwNzAyMDkwMTE4WhcNMjAwNjMwMDkwMTE4WjBaMQswCQYDVQQGEwJVUzET
      MBEGA1UECAwKQ2FsaWZvcm5pYTETMBEGA1UEBwwKQ2FsaWZvcm5pYTEhMB8G
      A1UECgwYSW50ZXJuZXQgV2lkZ2l0cyBQdHkgTHRkMIGfMA0GCSqGSIb3DQEB
      AQUAA4GNADCBiQKBgQC8ZtxM1bYickpgSVG-
      meHInI3f_chlMBdL8l7daOEztSs_a6GLqmvSu-
      AoDpTsfEd4EazdMBp5fmgLRGdCYMcI6bgpO94h5CCnlj8xFKPq7qGixdwGUA
      6b_ZI3c4cZ8eu73VMNrrn_z3WTZlExlpT9XVj-
      ivhfJ4a6T20EtMM5qwIDAQABo4GsMIGpMHQGA1UdIwRtMGuhXqRcMFoxCzAJ
      BgNVBAYTAlVTMRMwEQYDVQQIDApDYWxpZm9ybmlhMRMwEQYDVQQHDApDYWxp
      Zm9ybmlhMSEwHwYDVQQKDBhJbnRlcm5ldCBXaWRnaXRzIFB0eSBMdGSCCQCX
      9nxZBNQWDjAJBgNVHRMEAjAAMA4GA1UdDwEB_wQEAwIGwDAWBgNVHSUBAf8E
      DDAKBggrBgEFBQcDAzANBgkqhkiG9w0BAQUFAAOBgQAGkz9QpoxghZUWT4iv
      em4cIckfxzTBBiPHCjrrjB2X8Ktn8GSZ1MdyIZV8fwdEmD90IvtMHgtzK-
      9wo6Aibj_rVIpxGb7trP82uzc2X8VwYnQbuqQyzofQvcwZHLYplvi95pZ5fV
      rJvnYAUBFyfrdT5GjqL1nqH3a_Y3QPscuCjg"
    },
    "signature":"
    DfoBOetNelKsnAe_m4Z9K5UbihgWNYZsp5jVybiI05sOagDzv6R4do9npaAlAvpNK8HJ
    CxD6D22J8GDUExlIhSR1aDuDCQm6QzmjdkFdxAz5TRYl6zpPCZqgSToN_g1TZxqxEv6V
    Ob5fies4g6MHvCH-Il_-KbHq5YpwGxEEFdg"
  }
}
             

Authors' Addresses

Mingliang Pei Symantec 350 Ellis St Mountain View, CA 94043 USA EMail: mpei@yahoo.com
Nick Cook Intercede St. Mary's Road, Lutterworth Leicestershire, LE17 4PS Great Britain EMail: nick.cook@intercede.com
Minho Yoo Solacia 5F, Daerung Post Tower 2, 306 Digital-ro Seoul, 152-790 Korea EMail: paromix@sola-cia.com
Andrew Atyeo Intercede St. Mary's Road, Lutterworth Leicestershire, LE17 4PS Great Britain EMail: andrew.atyeo@intercede.com
Hannes Tschofenig ARM Ltd. 110 Fulbourn Rd Cambridge, CB1 9NJ Great Britain EMail: Hannes.tschofenig@arm.com