| Internet-Draft | EAP-CREDS | November 2023 |
| Pala & Tian | Expires 30 May 2024 | [Page] |
With the increase number of devices, protocols, and applications that rely on strong credentials (e.g., digital certificates, keys, or tokens) for network access, the need for a standardized credentials provisioning and management framework is paramount. The 802.1x architecture allows for entities (e.g., devices, applications, etc.) to authenticate to the network by providing a communication channel where different methods can be used to exchange different types of credentials. However, the need for managing these credentials (i.e., provisioning and renewal) is still a hard problem to solve. Usually, credentails used in an access network can be in different levels (e.g., network-level, user-level) and sometimes tend to live unmanaged for quite a long time due to the challenges of operation and implementation. EAP-CREDS (RFC XXXX), if implemented in Managed Networks (e.g., Cable Modems), could enable our operators to offer a registration and credentials management service integrated in the home WiFi thus enabling visibility about registered devices. During initialization, EAP-CREDS also allows for MUD files or URLs to be transferred between the EAP Peer and the EAP Server, thus giving detailed visibility about devices when they are provisioned with credentials for accessing the networks. The possibility provided by EAP-CREDS can help to secure home or business networks by leveraging the synergies of the security teams from the network operators thanks to the extended knowledge of what and how is registered/ authenticated. This specifications define how to support the provisioning and management of authentication credentials that can be exploited in different environments (e.g., Wired, WiFi, cellular, etc.) to users and/or devices by using EAP together with standard provisioning protocols.¶
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This Internet-Draft will expire on 30 May 2024.¶
Copyright (c) 2023 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 (https://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 Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License.¶
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 [RFC2119].¶
Many environments are, today, moving towards requiring strong authentication when it comes to gain access to networks. The 802.1x architecture provides network administrators with the possibility to check credentials presented by a device even before providing any connectivity or IP services to it. However, the provisioning and management of these credentials is a hard problem to solve and many vendors opt for long-lived credentials that can not be easily revoked, replaced, or simply renewed. This specification addresses the problem of providing a simple-to-use and simple-to-deploy conduit for credentials management by extending the EAP protocol to support credentials provisioning and management functionality. In particular, the EAP-CREDS method defined here provides a generic framework that can carry the messages for provisioning different types of credentials. EAP-CREDS cannot be used as a stand-alone method, it is required that EAP-CREDS is used as an inner method of EAP-TLS, EAP-TEAP, or any other tunneling method that can provide the required secrecy and (at minimum) server-side authentication to make sure that the communication is protected and with the right server.¶
Currently there are many protocols that address credentials lifecycle management. In particular, when it comes to digital certificates, some of the most deployed management protocols are: Certificate Management Protocol (CMP) [RFC4210], Certificate Management over CMS (CMC) [RFC5272][RFC6402], Enrollment over Secure Transport (EST) [RFC7030], and Automated Certificate Management Environment (ACME) [RFC8555]. However, none of these protocols provide native support for client that do not have IP connectivity yet (e.g., because they do not have network-access credentials, yet). EAP-CREDS provides the possibility to use such protocols (i.e., message-based) by defining a series of messages that can be used to encapsulate the provisioning messages for the selected provisioning protocol.¶
This document focuses on the definition of the EAP-CREDS method to convey credentials provisioning and managing messages between the client and the AAA server. Moreover, the document defines how to encode messages for the main IETF provisioning protocols. This document, however, does not provide specifications for how and where the credentials are generated. In particular, the credentials could be generated directly within the AAA server or at a different location (i.e., the Certificate Service Provider or CSP) site. Different authentication mechanisms (e.g., TLS, etc.) can be used to secure the communication between the server's endpoint and the CSP. Examples and details of how to use EAP-CREDS encapsulation mechanism with specific protocol are out of scope of this document. For more details of using EAP-CREDS method with Simple Provisioning Protocol (SPP), please refer to EAP-CREDS with Simple Provisioning Protocol (SPP) . For more details of using EAP-CREDS method with Certificate Management Protocol (CMP), please refer to EAP-CREDS withwith Certificate Management Protocol (CMP) . These two documents can be used as the template for other protocols' encapulation with EAP- CREDS.¶
EAP-CREDS requires that an outer mechanism is in place between the Peer and the Server in order to provide authentication and confidentiality of the messages exchanged via EAP-CREDS. In other words, EAP-CREDS assumes that an appropriately encrypted and authenticated channel has been established to prevent the possibility to leak information or to allow man-in-the-middle attacks.¶
This choice was taken to simplify the message flow between Peer and Server, and to abstract EAP-CREDS from the secure-channel establishment mechanism. EAP-TLS, or EAP-TEAP are examples of such mechanisms.¶
EAP does not directly support handling fragmented packets and it requires the outer method to provide fragmentation support.¶
Because of the outer method requirements in particular, removing any support for fragmented messages in EAP-CREDS removes the duplication of packets (e.g., Acknowledgment Packets) sent across the Peer and the Server, thus resulting in a smaller number of exchanged messages.¶
In order to use EAP-CREDS together with your favorite provisioning protocol, the messages from the provisioning protocol need to be sent to the other party. In EAP-CREDS, this is done by encoding the provisioning protocol messages inside the ('ProtoData') TLV. In case the provisioning protocol uses additional data for its operations (e.g., uses HTTP Headers), this data can be encoded in a separate ('ProtoHeaders') TLV.¶
Since the implementation of the provisioning endpoint could happen in a (logically or physically) different component, a method is needed to identify when a provisioning protocol has actually ended. In EAP- CREDS, the 'D' (Done) bit in the message headers is used for this purpose.¶
In the first message of Phase Two, the Server provides the client with all the selected parameters for one specific credential that needs attention (or for a new credential) to be managed by the network. In particular, the server provides, at minimum, the ('Protocol') TLV, the ('Action') TLV, and the ('Params') or the ('Creds-Info') TLV.¶
After checking the parameters sent by the Server, if the Peer does not support any of the proposed ones, it MUST send a message with one single ('Error') TLV with the appropriate error code(s). The server, can then decide if to manage a different set of credentials (if more where reported by the Peer in its Phase One message) or if to terminate the EAP session with an error.¶
The Peer and the Server exchange Provisioning messages until an error is detected (and the appropriate error message is sent to the other party) or until Phase Two is successfully completed.¶
EAP-CREDS uses the SHA-256 hashing algorithm to verify credentials in phase three of the protocol. Peers and Servers MUST support SHA-256 for this purpose.¶
In this document we use the following notation in the diagrams to provide information about the cardinality of the data structures (TLVs) within EAP-CREDS messages:¶
+--------+------------+---------------------------------------------+
| Symbol | Example | Usage |
+--------+------------+---------------------------------------------+
| { } | {TLV1} | Curly Brackets are used to indicate a set |
| [ ] | {[TLV2]} | Square Brackets are used to indicate that a |
| | | field is optional |
| ( ) | {TLV1(=V)} | Round Squares are used to specify a value |
| + | {TLV_2+} | The Plus character indicates that one or |
| | | more instances are allowed |
+--------+------------+---------------------------------------------+
In a nutshell, EAP-CREDS provides the abstraction layer on top of which credentials provisioning/managing protocols can be deployed thus enabling their use even before provisioning IP services.¶
This section outlines the operation of the protocol and message flows. The format of the CREDS messages is given in Section 4.¶
EAP-CREDS message flow is logically subdivided into three different phases: Initialization, Provisioning, and Validation. EAP-CREDS enforces the order of phases, i.e. it is not possible to move to an earlier phase.¶
Phase transitioning is controlled by the Server. In particular, the server, after the last message of a phase, it can decide to either (a) start the next phase by sending the first message of the next phase, or (b) continue the same phase by sending another "first" message of the phase (e.g., managing a second set of credentials) - this is allowed only in Phase Two and Phase Three but NOT in Phase One, or (c) terminate the EAP session.¶
In order to keep track of starting and ending a phase, EAP-CREDS defines several bits and fields in the EAP-CREDS message headers. In particular, as described in Section 4.1, the 'S' (Start) bit is used to indicate the beginning (or Start) of a phase, while the 'Phase' field (4 bits) is used to indicate the phase for this message.¶
In EAP-CREDS, phase transitioning is under the sole control of the Server, therefore the value of the 'S' (Start) bit is meaningful only in messages sent by the Server. The value of the 'S' (Start) bit in Peer's messages SHALL be set to '0x0' and SHALL be ignored by the server.¶
When starting a new phase, the Server MUST set the 'S' (Start) bit to '1' and the 'Phase' field to the current phase number (e.g., 0x01 for phase one, 0x02 for phase two, or 0x03 for phase three).¶
In case the first message of a phase is to be repeated (e.g., because of processing multiple credentials), the 'S' (Start) bit SHALL be set to '0' (i.e., it should be set to '1' only on the first occurrence and set to '0' in subsequent messages).¶
,--------. ,----------.
|EAP Peer| |EAP Server|
`---+----' `----+-----'
| Outer Tunnel Established |
| <--------------------------------------->
| |
| [1] EAP-Request/EAP-CREDS(Type=Init) | ,---------!.
| { [ Version+ ], [ Challenge-Data ] }| |Phase One|_\
| <---------------------------------------- |Begins |
| | `-----------'
| [2] EAP-Response/EAP-CREDS(Type=Init) |
| { [ Version+ ], [ Protocols+ ], |
| [ Creds-Info+ ], [ Encoding+ ], | ,---------!.
| [ Format+ ], [ Token ], | |Phase One|_\
| [ Profile+ ], [ Challenge-Rsp ], | |Ends |
| [ Storage-Info ],[ Net-Usage] } | `-----------'
| ---------------------------------------->
| |
| |
EAP-CREDS Phase One Message Flow
[1] Server sends EAP-Request/EAP-CREDS(Type=Init):
¶
The Peer, sends back a message that carries one ('Version') TLV to indicate the selected version of EAP-CREDS (i.e. from the list provided by the server) (optional). If the client does not include the ('Version') TLV, the Server MUST use the most recent supported version of EAP-CREDS. Moreover, the Server includes one or more ('Protocol') TLVs to indicate the list of supported provisioning protocols, followed by one ('Creds-Info') TLVs for each installed credentials to provide their status to the server (i.e., if multiple credentials are configured on the Peer for this Network, then the Peer MUST include one ('Creds-Info') TLV for each of them).¶
The Peer MAY also provide the list of supported Encodings and Formats by adding one or more ('Encoding') and ('Formats') TLVs. The Peer MAY also provide the Server with information about the Peer's credentials storage by using the ('Storage-Info') TLV.¶
When there are no available credentials, the Peer MAY include an authorization token that can be consumed by the Server for registering new credentials. In particular, the Peer can include the ('Token') TLV to convey the value of the token. The ('Challenge-Data') and ('Challenge-Response') TLVs, instead, can be used to convey a challenge and its response based on the authorization information. For example, suppose a public key hash is present in the Token, the peer can generate some random data - or use the one from the Server - and generate a signature on that value: the signature SHALL be encoded in the ('Challenge- Response') TLV and it should be calculated over the concatenation of values inside the ('Challenge-Data') TLV and the ('Token') TLV.¶
Also, the Peer MAY add one or more ('Profile') TLVs to indicate to the Server which profiles are requested/supported (e.g., a pre- configuration MAY exist on the Peer with these ecosystem-specific identifiers).¶
Ultimately, the Peer MAY include additional metadata regarding the status of the Peer. To this end, the Peer can use a ('Storage- Info') TLV to provide the server with additional data about the Peer's capabilities and resources. Also, the ('Net-Usage') TLV can be used to provide the Server with the indication of which network resources are needed by the Peer and what is its intended utilization pattern(s).¶
The server checks that the Peer's selected protocol, version, and parameters are supported and, if not (or if the server detects an error), it can (a) send a non-recoverable error message to the peer, notify the outer (tunneling) layer, and terminate the EAP- CREDS session, or (b) start phase one again by sending a new ('EAP-CREDS-Init') message that will also carry an ('ERROR') TLV that provides the Peer with the reason the initial response was not acceptable. In this case, the ('Phase') field MUST be omitted since it is not the first message of phase one. The server and the peer can repeat phase one until they reach an agreement or the session is terminated by the Server.¶
NOTE WELL: The determination of the need to start phase two or not is based on the contents of the ('Creds-Info') TLV sent by the Peer (e.g., a credential is about to expire or a credential is simply missing).¶
The following figure provides the message flow for Phase 2:¶
,--------. ,----------.
|EAP Peer| |EAP Server|
`---+----' `----+-----'
| [1] EAP-Request/EAP-CREDS(Type=Provisioning) |
| { Protocol, Action, | ,---------!.
| [ Creds-Info ], [ Params ], | |Phase Two|_\
| [ ProtoData ], [ ProtoHeaders ] } | |Begins |
| <---------------------------------------------- `-----------'
| |
| [2] EAP-Response/EAP-CREDS(Type=Provisioning) |
| { ProtoData, [ ProtoHeaders ] } |
| ---------------------------------------------->
| |
. .
. .
. .
. .
| [N] EAP-Response/EAP-CREDS(Type=Provisioning) |
| { [ Creds-Info ], [ ProtoData ], |
| [ ProtoHeaders ] } |
| <----------------------------------------------
| |
| [N+1] EAP-Request/EAP-CREDS(Type=Provisioning)| ,---------!.
| { [ ProtoData ], [ ProtoHeaders ] } | |Phase Two|_\
| ----------------------------------------------> |Ends |
| | `-----------'
| |
EAP-CREDS Phase Two Message Flow
¶
At this point, the Server can decide to provision (or manage) another set of credentials by issuing a new ('Type=Provisioning') message, or it can decide to start Phase Three by sending its first ('Type=Validate') message, or it can terminate the EAP session.¶
,--------. ,----------.
|EAP Peer| |EAP Server|
`---+----' `----+-----'
| [1] EAP-Request/EAP-CREDS(Type=Validate) | ,-----------!.
| { Creds-Info, Challenge-Data } | |Phase Three|_\
| <----------------------------------------- |Begins |
| | `-------------'
| [2] EAP-Response/EAP-CREDS(Type=Validate)| ,-----------!.
| { Challenge-Response } | |Phase Three|_\
| -----------------------------------------> |Ends |
| | `-------------'
| |
EAP-CREDS Phase Three Message Flow
¶
Phase three is optional and it is used by the server to request the client to validate (with proof) that the new credentials have been installed correctly before issuing the final EAP-CREDS Success message.¶
In order to start Phase Three, the Server sends an EAP-Request/ EAP-CREDS(Type=Validate) message to the Peer. The Server MUST include the ('Creds-Info') TLV to provide the indication about which set of credentials the Server intends to validate. The Server MUST also include a randomly generated challenge in the message to the client. The type of challenge determines in ('Challenge-Data') for the peer to calculate ('Challenge- Response'). EAP-CREDS defines the asymmetric and symmetric challenges in Section 7.5 and others can be defined according to the specified rules.¶
As usual, the Server MUST set, in the headers, the 'S' (Start) bit to '1' in its first message of Phase Three and the 'Phase' value shall be set to '3' (beginning of Phase Three).¶
When the client receives the Validate message from the server, it calculates the response to the challenge and sends the response back to the server in a EAP-Response/EAP-CREDS(Type=Validate) message. When the 'EAP-CREDS-ASYMMETRIC-CHALLENGE' and 'EAP- CREDS-SYMMETRIC-CHALLENGE' values are used in the 'Challenge types', the Peer MUST calculate the response as follows:¶
Public-Key¶
For any public-key based credentials (e.g., certificates or raw key pairs), the response to the challenge is calculated by generating a signature over the hashed value of the challenge. The hashing algorithm to be used for this purpose is specified in Section 2.6. The format of the signature in the ('Challenge-Response') TLV is the concatenation of:¶
For any symmetric based credentials (e.g., password or Key), the response to the challenge is calculated by using the selected hash function (see Section 2.6) on the concatenation of (a) the value carried in the server- provided ('Challenge-Data') TLV, and (b) the secret value itself (salted hash).¶
The initial values for the type of challenges are described in the Section 7.5. Other types of challenges MAY be defined according to the specified procedures.¶
In case of issues with the validation of newly deployed credentials, both the Server and the Peer should consider those credentials invalid (or unusable) and should issue the required failure message(s).¶
The EAP-CREDS defines the following message types:¶
Each of these message types have the basic structure as identified in Section 4.1. EAP-CREDS messages contain zero, one, or more TLVs. The internal structure of the different types of TLVs is described in Section 4.2, while a detailed description of the EAP-CREDS message types is provided in Section 5.¶
The EAP-CREDS messages consist of the standard EAP header (see Section 4 of [RFC3748]), followed by the message payload of the EAP- CREDS. The header has the following structure:¶
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Code | Identifier | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type |J|S|F|D| Phase | Message Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Message Length | Data ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-.¶
Where the Code, Identifier, Length, and Type fields are all part of the EAP header as defined in [RFC3748]. Since EAP-CREDS can only be used as a tunneled mechanism, the presence of these fields is only for backward compatibility with existing parsers. In particular, the 'Length' field is used for fragmentation instead of the message length: the message length is carried in the 'Message Length' field if Jumbo Message is indicated in the header.¶
The Type field in the EAP header is <TBD> for EAP-CREDS.¶
The Flags bitfield is used to convey status information (e.g., extra long message, phase number, phase transitioning state). The transition-control bit (i.e., the 'S' (Start) bit) are set in Server's messages and are ignored in Peer's messages (the Server is the entity that unilaterally controls the phase transition process). The meanings of the bits in the 'Flags' field are as follows:¶
The Phase field is a 4-bits value and identifies the EAP-CREDS phase for the current message. The version of EAP-CREDS described in this document supports three values for this field:¶
A detailed explanation of the 'Phase' and 'Flags' fields of the message headers is provided in Section 3.2.¶
The Data field is the message payload. The full description of this field is provided in the next section.¶
The Data part of the message is organized as zero, one, or more TLV objects whose structure is defined in this section.¶
Each TLV object has the same basic structure that is defined as follows:¶
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV Type | TLV Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV Value ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Where: TLV-Type (uint8)¶
| TLV Name | TLV Type | Scope/Usage |
|---|---|---|
| <TBD> | Action TLV | Phase Two |
| <TBD> | Certificate-Data TLV | Phase Two |
| <TBD> | Challenge-Data TLV | Phase Two, Phase Three |
| <TBD> | Challenge-Response TLV | Phase Two, Phase Three |
| <TBD> | Credentials-Data TLV | Phase Two |
| <TBD> | Creds-Info TLV | Phase Two, Phase Three |
| <TBD> | Error TLV | All Phases |
| <TBD> | Net-Usage TLV | Phase One |
| <TBD> | Profile TLV | Phase Two |
| <TBD> | Protocol TLV | Phase One, Phase Two |
| <TBD> | ProtoData TLV | Phase Two |
| <TBD> | ProtoHeaders TLV | Phase Two |
| <TBD> | Params TLV | Phase Two |
| <TBD> | Token TLV | Phase One |
| <TBD> | Version TLV | Phase One |
The rest of this section describes the structure of the different supported TLVs and their usage in the different messages.¶
EAP-CREDS messages's payload comprises zero, one, or more TLVs that are encoded in a single EAP-CREDS message. The values for the TLV Type that are supported by this specifications are listed in Table 2.¶
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV Type | TLV Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | Action Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TLV Type (uint8) <TBD> - Action TLV TLV Length (uint24) Fixed value (=2) Flags (uint8) Reserved¶
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV Type | TLV Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Ch. Type | Challenge Data ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TLV Type (uint8) <TBD> - Challenge-Data TLV Length (uint24) 3 octets Challenge Type (uint8)¶
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV Type | TLV Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Challenge Response ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TLV Type (uint8) <TBD> - Challenge-Response TLV Length (uint24) 3 octets Challenge Response (> 1 octet)¶
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV Type | TLV Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | CredsType | ProtoID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | IssuedOn (GMT) | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | ExpiresOn (GMT) | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Credentials Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | CredIDValue ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+¶
The Creds-Info TLV is used by the Peer to provide a description of the installed credentials that are relevant for the network that is being accessed.¶
For example, when a set of credentials need to be renewed, the server checks the ('Creds-Info') from the Peer and eventually selects the right one for renewal. The TLV structure is as follows:¶
Provides a BITMASK that can be used to provide information about the status of the credentials (e.g., if the use marks the credentials to be compromised). The bits have the following meaning:¶
Bit 0 - If set, the credential is marked as compromised Bit 1 - If set, the credential is immutable and cannot be updated¶
Bit 2 - Private Key or Secret Immutable, the public part of the credential (e.g., a certificate) can still be updated¶
Bit 3 - If set, the credential cannot be updated (both public and private parts)¶
Bit 4 - If set, the credential is ready to be used¶
Bit 5 - If set, the credential was generated on the server¶
Bit 6 - If set, the Peer would like to update the credential even if they are not expired¶
Bit 7 - Reserved¶
This field carries the GMT date for when this credential was issued. This field is 16 bytes long (the last byte must be set to '0x00') and contains the NULL-terminated ASCII string that represents the timestamp where the credential was issued. When the value is not set, the field should be set to { 0x00 }. The format of the string is as follows:¶
YYYYMMDDHHmmssZ¶
YYYY - is the 4 digits representation of the year¶
MM - is the 2 digits representation of the month DD - is the 2 digits representation of the day of the month¶
HH - is the 2 digits representation of the hour of the day (24 hour format)¶
mm - is the 2 digits representation of the minutes of the hour¶
ss - is the 2 digits representation of the seconds of the minute¶
Z - is the character 'Z'¶
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV Type | TLV Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | EAP-CREDS Error Code | Secondary Error Code | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Description ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TLV Type (uint8) <TBD> - Challenge-Response-Data TLV Length (uint24) 3 octets EAP-CREDS Error Code (2 octets)¶
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV Type | TLV Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |U| Desc Format | Encoding | Net-Usage Data ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TLV Type (uint8) <TBD> - Net-Usage TLV Length (uint24) Variable Length TLV (Value must be > 2 ) Desc Format (7 bits)¶
The 'URL' bit ('U') is used to indicate if the value of the Net- Usage Data field is to be interpreted as a URL or as the actual data. In particular, if the value in the 'URL' bit is '1', then the value in the Net-Usage Data field is to be interpreted as the URL where the actual data can be downloaded from. Otherwise, if the 'URL' bit is set to '0', then the value in the Net-Usage Data field is to be interpreted as the actual data (not a URL referencing it).¶
An example use of this bit is when the Peer wants to convey the URL of the MUD file [RFC8520]. In this case, the Peer can set the Net-Usage Data field to the URL of the MUD file related to the Peer.¶
This is additional information related to the device. In particular, this TLV can be used by the Peer to provide the Server with the description of the intended network usage or a URL that points to the same information.¶
For example, this field can be used to convey a MUD file (Manufacturer Usage Description) or the latest firmware-update manifest.¶
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV Type | TLV Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Profile Identifier ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TLV Type (uint8) <TBD> - Profile Identifying Data TLV Length (uint24) Length value should be >= 1 Profile Identifier (octet string)¶
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV Type | TLV Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Protocol ID | Version | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TLV Type (uint8) <TBD> - Protocol TLV TLV Length (uint24) Fixed TLV Length value of 4. Protocol ID (uint16)¶
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV Type | TLV Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Provisioning Data ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TLV Type (uint8) <TBD> - ProtoData TLV Length (uint24) 3 octets Headers Data (> 1 octet) This field carries the provisioning protocol's messages.¶
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV Type | TLV Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Headers Data ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TLV Type (uint8) <TBD> - ProtoHeaders TLV Length (uint24) 3 octets Headers Data (> 1 octet)¶
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV Type | TLV Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Min Length | Max Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Algorithm | Flags | OBJECT IDENTIFIER (DER) ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TLV Type (uint8) <TBD> - Params TLV Length (uint24) Provides the length of the TLV (>= 6 octets) Min Length (uint16)¶
Provides the indication maximum size of the credentials. This value has meaning depending on the context of the credentials, however sizes are always expressed in bytes.¶
The same considerations apply to this field as well as the ('Min Length') one discussed above.¶
Provides a BITMASK that can be used to provide information about the status of the credentials (e.g., if the use marks the credentials to be compromised). The bits have the following meaning:¶
Bit 0 - Credentials (or part of it) are to be generated on the server¶
Bit 1 - Credentials (or part of it) are to be generated on the peer¶
Bit 2 - Credentials are to be generated on dedicated hardware¶
Bit 3 - Reserved¶
Bit 4 - Reserved¶
Bit 5 - Reserved¶
Bit 6 - Reserved¶
Bit 7 - Reserved¶
When using public-key based credentials, the bits 0 and 1 are mutually exclusive.¶
When using passwords or shared secrets, if bit 0 is set, then the secret is generated by the server and then sent to the client. On the other hand, if bit 1 is set, then the secret is generated by the peer and then sent to the server. Ultimately, if both bits are set, then the Server generates the first part of the password and sends it to the Peer, while the Peer generates the second part of the password and sends it to the Server. The password to be used for future authentication is the concatenation of the two shares of the password: first the one from the Server, then the one from the Client.¶
NOTE WELL: Last but not least, since these passwords/secrets are meant to be used in a automated fashion, there is no restriction around the character set to use or their interpretation. Therefore, it is good practice to generate random pass-phrases that use the full 8-bit character set (on client and server) to maximize the secret's search space.¶
| OID Name | Dotted Representation | Binary Encoding |
|---|---|---|
| secp256r1 | 1.2.840.10045.3.1.7 | 06 08 2A 86 48 CE 3D 03 |
| curve | 01 07 | |
| secp384r1 | 1.2.840.10045.3.1.34 | 06 08 2A 86 48 CE 3D 03 |
| curve | 01 22 | |
| secp521r1 | 1.2.840.10045.3.1.35 | 06 08 2A 86 48 CE 3D 03 |
| curve | 01 23 | |
| X25519 curve | 1.3.101.110 | 06 03 2B 65 6E |
| X25519 curve | 1.3.101.110 | 06 03 2B 65 6E |
| X448 curve | 1.3.101.111 | 06 03 2B 65 6F |
| Ed25519 curve | 1.3.101.112 | 06 03 2B 65 70 |
| Ed448 curve | 1.3.101.113 | 06 03 2B 65 71 |
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV Type | TLV Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Token Type | Encoding | Value ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TLV Type (uint8) <TBD> - Token TLV TLV Length (uint24) Provides the length of the TLV (> 3 octets) Token Type (uint8)¶
0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TLV Type | TLV Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Version | +-+-+-+-+-+-+-+-+ TLV Type (uint8) <TBD> - Version TLV TLV Length (uint24)¶
The Version field represents the specific version of the EAP-CREDS protocol that are supported by the end point. When multiple versions of EAP-CREDS are supported, multiple ('Version') TLVs can be used.¶
When no version is specified (i.e., either it does not support multiple versions or it does not matter), the value of this field should be set to '0x0' (any version).¶
This section describes each message and what TLVs are allowed or required. EAP-CREDS defines the following values for the Message Type (Type):¶
| Message Type | Name | Description |
|---|---|---|
| 0 | EAP-CREDS-Init | Initialization Phase; |
| 1 | EAP-CREDS-Provisioning | Carries Provisioning |
| Protocol Messages; | ||
| 2 | EAP-CREDS-Validate | Validates newly installed |
| credentials; |
The EAP-CREDS-Init message type is used in Phase One only of EAP- CREDS. The message flow is depicted in Section 3.3. This message supports the following TLVs: Version, Protocol, Creds-Info, and Error.¶
EAP-CREDS starts with an ('EAP-CREDS-Init') message from the server. This message MAY contain zero, one, or more ('Version') TLVs and, optionally, a ('Challenge-Data') TLV.¶
The first message from the server is the one that starts Phase One, therefore the Server MUST set the headers' 'S' (Start) bit to '1' (Start) and the headers' 'Phase' value to '1' (Phase One).¶
The Server uses one or more ('Version') TLVs in the EAP-Request/EAP- CREDS(Type=Init) message to provide the Peer with the list of EAP- CREDS versions supported. If omitted, the implicit version of EAP- CREDS used in the session is one ('0x1'). If the Server detects multiple occurrences of this TLV in the reply from the Peer, an error shall be issued and the EAP-CREDS session should be terminated.¶
In case Token-Based registration is enabled on the Server, the Server MUST include, in its Init message, a ('Challenge-Data') field that can be used by the client to provide challenge data for proof-of- possession of secrets.¶
The Peer MUST reply to the Server's ('EAP-CREDS-Init') message with its own ('EAP-CREDS-Init') one. The Peer SHOULD include one ('Version') TLV in its first message to indicate the version of EAP- CREDS that the client wants to use for the session. The Peer MUST also provide the list of supported provisioning protocols (via one or more the 'Protocol' TLV), the list and status of the installed credentials (via the 'Creds-Info' TLV). The Peer MAY include authorization data when registering new credentials (e.g., an authorization token or a device certificate) via the ('Token') and ('Challenge-Response') TLV.¶
The Peer MUST include one ('Creds-Info') TLV for each credential the Network is authorized to manage. Typically, a Peer will include only one ('Creds-Info') TLV in its ('EAP-CREDS-Init') message, but there might be cases where multiple types of credentials are available and selected depending on the location and other factors (e.g., X.509 certificate and username/password combination).¶
In case the Peer does not have any credentials available yet, it does not add any ('Creds-Info') TLV - leaving the Server with the only action possible: Registration. In this case, the Peer SHOULD include authorization information via the ('Token') TLV as described in Section 5.1.2.1. Additionally, the Peer can add the ('Profile') TLV to indicate a preferred profile for the credentials.¶
When the Peer does not have any valid credentials for the Network that it is authenticating to, it does not provide any ('Creds-Info') TLV. This indicates to the Server that new credentials MUST be registered before the Peer is allowed on the network.¶
The Registration process might rely on information exchanged during the Provisioning Process in Phase Two. However, if an authorization mechanism is not available from the supported provisioning protocol and no credentials are available on the Peer, EAP-CREDS provides a simple mechanism for the Peer to leverage an out-of-band token/passphrase/ott that may be already available on the Peer (e.g., a device certificate or a 'spendable' credentials token like a kerberos ticket or a crypto-currency transaction) and that can be verified by the Server.¶
In particular, when the Peer wants to register new credentials (and the Server requires the use of additional authorization data) it may need to provide (a) a Token, (b) a challenge value, and (c) a response to the challenge value. To do so, the Peer MUST encode the token in a ('Token') TLV, the challenge value in a ('Challenge-Data') TLV, and, finally, the response to the challenge in the ('Challenge- Response') TLV.¶
The use of ('Challenge-Data') and ('Challenge-Response') TLVs is optional, however it is suggested that if a token is used for bootstrapping the trust, it should provide a way to verify a secret associated with it.¶
It is also very important that the authorization token is disclosed only to authorized servers - the Peer MUST NOT disclose authorization tokens that are not meant for the network that is being accessed. This can be done, usually, by verifying the identity of the Server first (in the outer mechanism) and then verify that the target of the Token is the Server the Client is talking to.¶
The EAP-CREDS-Provisioning message type is used in Phase Two only of EAP-CREDS. The message flow is depicted in Section 3.4. This message type supports the following TLVs: Protocol, Profile, Creds- Info, ProtoHeaders, ProtoData, Token, and Error.¶
After the exchange of phase one messages, the Server MAY start phase two by issuing an ('EAP-CREDS-Provisioning') message for the Peer where it encodes all the required details for starting the provisioning process. In particular, the server sends the selected ('Action'), ('Protocol'), and metadata to the client in a EAP- Request/EAP-CREDS(Type=Provisioning) message. The header's 'S' (Start) bit MUST be set to '1' (Start) and the 'Phase' value set to '2' (Phase Two begins).¶
The client checks that all the selected parameters are supported for the selected credentials and, if no errors are detected, it sends its first ('EAP-CREDS-Provisioning') message to the Server with the ('ProtoHeaders') and ('ProtoData') TLVs only.¶
From now on, the conversation between the Peer and the Server continues until an error is detected or the provisioning protocol completes successfully.¶
If no other actions, the server MAY continue with phase three or issue a success message and terminate the EAP session.¶
The EAP-CREDS-Validate message type is used in Phase Three only of EAP-CREDS. The message flow is depicted in Section 3.5. This message type supports the following TLVs: Protocol, Creds-Info, ProtoHeaders, ProtoData, Token, and Error.¶
After Phase One (and/or Phase Two) ends, the Server MAY start phase three by issuing an ('EAP-CREDS-Validate') message for the Peer where it encodes all the required details for starting the validation process. In particular, the server sends the ('Creds-Info'), a ('Challenge-Data'), and the ('Phase') fields in a EAP-Request/EAP- CREDS(Type=Validate) message. The ('Phase') field should carry the '1' value for the 'S' (Start) bit (Start) and the number '3' for its value (Phase Three begins).¶
The Peer generates the answer to the Challenge and sends back a EAP- Response/EAP-CREDS(Type=Validate) message with the ('Challenge- Response') and an optional ('Challenge-Data') field (only for server- side validation of the symmetric credentials). If the Peer requested server-side validation of the credentials, the Server MUST include (if a symmetric secret) the response to the Peer-issued ('Challenge- Data') TLV by computing the response and adding it to the ('Challenge-Response') TLV in its reply.¶
Finally, in the last message, the Server (if Phase Three is to be ended) SHALL include the ('Phase') field with the 'S' (Start) bit set to '0' (end of phase) and the value set to '3' (Phase Three ended).¶
At this point, EAP-CREDS has terminated all possible operations and can be terminated. The Server can now terminate the EAP session successfully. In case the Peer was not authenticated during the tunnel establishment (i.e., no credentials were already available on the Peer), the Server should terminate the EAP session with a Failure (thus requiring the device to re-attach and authenticate to the network - phase two should have provided the Peer with the credentials to use for authenticating to the Network).¶
This section provides a description of the error handling by using the CREDS-Error-TLV in a CREDS message. <TBD>¶
This document uses a new EAP type, EAP-CREDS, whose value (TBD) MUST be allocated by IANA from the EAP TYPEs sub-registry of the RADIUS registry. This section provides guidance to the Internet Assigned Numbers Authority (IANA) regarding registration of values related to the EAP-CREDS protocol, in accordance with [RFC8126].¶
The EAP Method Type number for EAP-CREDS needs to be assigned.¶
This document also requires IANA to create new registries as defined in the following subsections.¶
| Message Type | Purpose |
|---|---|
| 0 | Unspecified |
| 1 | Simple Provisioning Protocol (SPP) |
| 2 | Basic Certificate Management Protocol (CMP-S) |
| 3 | Full Certificate Management Protocol (CMP-F) |
| 4 | Enrollment over Secure Transport (EST) |
| 5 | Certificate Management over CMS (CMC) |
| 6 | Automatic Certificate Management Environment |
| (ACME) | |
| ... | ... |
| 49141 ... 65534 | Vendor Specific |
Assignment of new values for new cryptosuites MUST be done through IANA with "Specification Required" and "IESG Approval" as defined in [RFC8126].¶
| Token Type | Description |
|---|---|
| 0 | Unspecified |
| 1 | JWT |
| 2 | Kerberos |
| 3 | OAuth |
| 4 | Certificate |
| 200..254 | Vendor Specific |
Assignment of new values for new Message Types MUST be done through IANA with "Expert Review" as defined in [RFC8126].¶
| Credentials Type | Description |
|---|---|
| 0 | X.509 Certificate |
| 1 | Public Key |
| 2 | Symmetric Key |
| 3 | Username and Password |
| 4 | AKA Subscriber Key |
| 5 | Bearer Token |
| 6 | One-Time Token |
| 7 | API Key |
Assignment of new values for new Message Types MUST be done through IANA with "Expert Review" as defined in [RFC8126].¶
| ID | Algorithm |
|---|---|
| 0 | None |
| 1 | RSA |
| 2 | ECDSA |
| 3 | XMMS |
| 4 | AKA Subscriber Key |
| 5 | OAuth |
| 6 | Kerberos4 |
| 7 | Kerberos5 |
| 200-254 | Reserved |
Assignment of new values for new Message Types MUST be done through IANA with "Expert Review" as defined in [RFC8126].¶
| ID | Data Type |
|---|---|
| 0 | Not Specified |
| 1 | EAP-CREDS-ASYMMETRIC |
| 2 | EAP-CREDS-SYMMETRIC |
Assignment of new values for new Message Types MUST be done through IANA with "Expert Review" as defined in [RFC8126].¶
| ID | Data Type |
|---|---|
| 0 | Vendor-Specific |
| 1 | Manufacturer Usage Description [RFC8520] |
| 2 | Network Access Granting System |
| 3 | Firmware Manifest |
| 4..127 | Reserved for Future Use |
Assignment of new values for new Message Types MUST be done through IANA with "Expert Review" as defined in [RFC8126].¶
| ID | Encoding |
|---|---|
| 0 | None (Raw) |
| 1 | DER |
| 2 | PEM |
| 3 | Base64 |
| 4 | JSON |
| 5 | XML |
| 6 | ASCII |
| 7 | UTF-8 |
| 200-254 | Reserved |
Assignment of new values for new Message Types MUST be done through IANA with "Expert Review" as defined in [RFC8126].¶
| ID | Data Type | Description |
|---|---|---|
| 0 | Registration | Registers New Credentials |
| 1 | Renewal | Renew an Existing Credential |
| 2 | Remove | Removes an Existing Credential |
| 200-254 | n/a | Reserved |
Assignment of new values for new Message Types MUST be done through IANA with "Expert Review" as defined in [RFC8126].¶
| Type | Description |
|---|---|
| 0 | Binary (Unspecified) |
| 1 | MUD File |
| 2 | TEEP Manifest |
Assignment of new values for new Message Types MUST be done through IANA with "Expert Review" as defined in [RFC8126].¶
Several security considerations need to be explicitly considered for the system administrators and application developers to understand the weaknesses of the overall architecture.¶
The most important security consideration when deploying EAP-CREDS is related to the security of the outer channel. In particular, EAP- CREDS assumes that the communication channel has been properly authenticated and that the information exchanged between the Peer and the Server are protected (i.e., confidentiality and integrity).¶
For example, if certificate-based authentication is used, the server presents a certificate to the peer as part of the trust establishment (or negotiation). The peer SHOULD verify the validity of the EAP server certificate and SHOULD also examine the EAP server name presented in the certificate in order to determine whether the EAP server can be trusted. When performing server certificate validation, implementations MUST provide support for the rules in [RFC5280] for validating certificates against a known trust anchor.¶
The authors would like to thank everybody who provided insightful comments and helped in the definition of the deployment considerations.¶