Signing HTTP Messages

1.1. Requirements Discussion

HTTP permits and sometimes requires intermediaries to transform messages in a variety of ways. This may result in a recipient receiving a message that is not bitwise equivalent to the message that was originally sent. In such a case, the recipient will be unable to verify a signature over the raw bytes of the sender's HTTP message, as verifying digital signatures or MACs requires both signer and verifier to have the exact same signed content. Since the raw bytes of the message cannot be relied upon as signed content, the signer and verifier must derive the signed content from their respective versions of the message, via a mechanism that is resilient to safe changes that do not alter the meaning of the message.¶

For a variety of reasons, it is impractical to strictly define what constitutes a safe change versus an unsafe one. Applications use HTTP in a wide variety of ways, and may disagree on whether a particular piece of information in a message (e.g., the body, or the Date header field) is relevant. Thus a general purpose solution must provide signers with some degree of control over which message content is signed.¶

HTTP applications may be running in environments that do not provide complete access to or control over HTTP messages (such as a web browser's JavaScript environment), or may be using libraries that abstract away the details of the protocol (such as the Java HTTPClient library). These applications need to be able to generate and verify signatures despite incomplete knowledge of the HTTP message.¶

1.2. HTTP Message Transformations

As mentioned earlier, HTTP explicitly permits and in some cases requires implementations to transform messages in a variety of ways. Implementations are required to tolerate many of these transformations. What follows is a non-normative and non-exhaustive list of transformations that may occur under HTTP, provided as context:¶

• Re-ordering of header fields with different header field names ([MESSAGING], Section 3.2.2).¶
• Combination of header fields with the same field name ([MESSAGING], Section 3.2.2).¶
• Removal of header fields listed in the Connection header field ([MESSAGING], Section 6.1).¶
• Addition of header fields that indicate control options ([MESSAGING], Section 6.1).¶
• Addition or removal of a transfer coding ([MESSAGING], Section 5.7.2).¶
• Addition of header fields such as Via ([MESSAGING], Section 5.7.1) and Forwarded ([RFC7239], Section 4).¶

1.3. Safe Transformations

Based on the definition of HTTP and the requirements described above, we can identify certain types of transformations that should not prevent signature verification, even when performed on content covered by the signature. The following list describes those transformations:¶

• Combination of header fields with the same field name.¶
• Reordering of header fields with different names.¶
• Conversion between different versions of the HTTP protocol (e.g., HTTP/1.x to HTTP/2, or vice-versa).¶
• Changes in casing (e.g., "Origin" to "origin") of any case-insensitive content such as header field names, request URI scheme, or host.¶
• Addition or removal of leading or trailing whitespace to a header field value.¶
• Addition or removal of obs-folds.¶
• Changes to the request-target and Host header field that when applied together do not result in a change to the message's effective request URI, as defined in Section 5.5 of [MESSAGING].¶

Additionally, all changes to content not covered by the signature are considered safe.¶

1.4. Conventions and Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶

The terms "HTTP message", "HTTP request", "HTTP response", absolute-form, absolute-path, "effective request URI", "gateway", "header field", "intermediary", request-target, "sender", and "recipient" are used as defined in [MESSAGING].¶

The term "method" is to be interpreted as defined in Section 4 of [SEMANTICS].¶

For brevity, the term "signature" on its own is used in this document to refer to both digital signatures and keyed MACs. Similarly, the verb "sign" refers to the generation of either a digital signature or keyed MAC over a given input string. The qualified term "digital signature" refers specifically to the output of an asymmetric cryptographic signing operation.¶

In addition to those listed above, this document uses the following terms:¶

Signer:

The entity that is generating or has generated an HTTP Message Signature.¶

Verifier:

An entity that is verifying or has verified an HTTP Message Signature against an HTTP Message. Note that an HTTP Message Signature may be verified multiple times, potentially by different entities.¶

The term "Unix time" is defined by [POSIX.1] section 4.16.¶

This document contains non-normative examples of partial and complete HTTP messages. To improve readability, header fields may be split into multiple lines, using the obs-fold syntax. This syntax is deprecated in [MESSAGING], and senders MUST NOT generate messages that include it.¶

Additionally, some examples use '\' line wrapping for long values that contain no whitespace, as per [RFC8792].¶

1.5. Application of HTTP Message Signatures

HTTP Message Signatures are designed to be a general-purpose security mechanism applicable in a wide variety of circumstances and applications. In order to properly and safely apply HTTP Message Signatures, an application or profile of this specification MUST specify all of the following items:¶

• The set of content identifiers (Section 2) that are expected and required. For example, an authorization protocol could mandate that the Authorization header be covered to protect the authorization credentials and mandate the signature parameters contain a created parameter, while an API expecting HTTP message bodies could require the Digest header to be present and covered.¶
• A means of retrieving the key material used to verify the signature. An application will usually use the keyid parameter of the signature parameters Section 2.4.2 and define rules for resolving a key from there, though the appropriate key could be known from other means.¶
• A means of determining the signature algorithm used to verify the signature content is appropriate for the key material. For example, the process could use the alg parameter of the signature parameters Section 2.4.2 to state the algorithm explicitly, derive the algorithm from the key material, or use some pre-configured algorithm agreed upon by the signer and verifier.¶
• A means of determining that a given key and algorithm presented in the request are appropriate for the request being made. For example, a server expecting only ECDSA signatures should know to reject any RSA signatures, or a server expecting asymmetric cryptography should know to reject any symmetric cryptography.¶

The details of this kind of profiling are the purview of the application and outside the scope of this specification.¶

2.1. HTTP Headers

The content identifier for an HTTP header is the lowercased form of its header field name. While HTTP header field names are case-insensitive, implementations MUST use lowercased field names (e.g., content-type, date, etag) when using them as content identifiers.¶

Unless overridden by additional parameters and rules, the HTTP header field value MUST be canonicalized with the following steps:¶

1. Create an ordered list of the field values of each instance of the header field in the message, in the order that they occur (or will occur) in the message.¶
2. Strip leading and trailing whitespace from each item in the list.¶
3. Concatenate the list items together, with a comma "," and space " " between each item.¶

The resulting string is the canonicalized value.¶

HTTP/1.1 200 OK
Server: www.example.com
Date: Tue, 07 Jun 2014 20:51:35 GMT
X-OWS-Header:   Leading and trailing whitespace.
X-Obs-Fold-Header: Obsolete
    line folding.
X-Empty-Header:
Cache-Control: max-age=60
Cache-Control:    must-revalidate

2.2. Dictionary Structured Field Members

An individual member in the value of a Dictionary Structured Field is identified by using the parameter key on the content identifier for the header. The value of this parameter is a the key being identified, without any parameters present on that key in the original dictionary.¶

An individual member in the value of a Dictionary Structured Field is canonicalized by applying the serialization algorithm described in Section 4.1.2 of [RFC8941] on a Dictionary containing only that member.¶

X-Dictionary:  a=1, b=2;x=1;y=2, c=(a b c)

2.3. List Prefixes

A prefix of a List Structured Field consisting of the first N members in the field's value (where N is an integer greater than 0 and less than or equal to the number of members in the List) is identified by the parameter prefix with the value of N as an integer.¶

A list prefix value is canonicalized by applying the serialization algorithm described in Section 4.1.1 of [RFC8941] on a List containing only the first N members as specified in the list prefix, in the order they appear in the original List.¶

X-List-A: (a b c d e f)
X-List-B: ()

2.4. Specialty Content Fields

Content not found in an HTTP header can be included in the signature base string by defining a content identifier and the canonicalization method for its content.¶

To differentiate specialty content identifiers from HTTP headers, specialty content identifiers MUST start with the "at" @ character. This specification defines the following specialty content identifiers:¶

@request-target

The target request endpoint. Section 2.4.1¶

@signature-params

The signature metadata parameters for this signature. Section 2.4.2¶

Additional specialty content identifiers MAY be defined and registered in the HTTP Signatures Specialty Content Identifier Registry. Section 5.3¶

POST /?param=value HTTP/1.1
Host: www.example.com

POST /a/b HTTP/1.1
Host: www.example.com

GET http://www.example.com/a/ HTTP/1.1

GET http://www.example.com HTTP/1.1

CONNECT server.example.com:80 HTTP/1.1
Host: server.example.com

OPTIONS * HTTP/1.1
Host: server.example.com

# NOTE: '\' line wrapping per RFC 8792
("@request-target" "host" "date" "cache-control" "x-empty-header"
  "x-example"); keyid="test-key-a"; alg="rsa-pss-sha512"; \
  created=1402170695; expires=1402170995

# NOTE: '\' line wrapping per RFC 8792
"@signature-params": ("@request-target" "host" "date" "cache-control" \
  "x-empty-header" "x-example" "x-dictionary";key=b \
  "x-dictionary";key=a "x-list";prefix=3); keyid="test-key-a"; \
  alg="rsa-pss-sha512"; created=1402170695; expires=1402170995

2.5. Creating the Signature Input String

The signature input is a US-ASCII string containing the content that is covered by the signature. To create the signature input string, the signer or verifier concatenates together entries for each identifier in the signature's covered content and parameters using the following algorithm:¶

1. Let the output be an empty string.¶

2. For each covered content item in the covered content list (in order):¶

   1. Append the identifier for the covered content serialized according to the content-identifier rule.¶
   2. Append a single colon ":"¶
   3. Append a single space " "¶
   4. Append the covered content's canonicalized value, as defined by the covered content type. Section 2.1 and Section 2.4¶
   5. Append a single newline "\\n"¶

3. Append the signature parameters Section 2.4.2 as follows:¶

   1. Append the identifier for the signature parameters serialized according to the content-identifier rule, "@signature-params"¶
   2. Append a single colon ":"¶
   3. Append a single space " "¶
   4. Append the signature parameters' canonicalized value as defined in Section 2.4.2¶
4. Return the output string.¶

If covered content references an identifier that cannot be resolved to a value in the message, the implementation MUST produce an error. Such situations are included but not limited to: * The signer or verifier does not understand the content identifier. * The identifier identifies a header field that is not present in the message or whose value is malformed. * The identifier is a Dictionary member identifier that references a header field that is not present in the message, is not a Dictionary Structured Field, or whose value is malformed. * The identifier is a List Prefix member identifier that references a header field that is not present in the message, is not a List Structured Field, or whose value is malformed. * The identifier is a Dictionary member identifier that references a member that is not present in the header field value, or whose value is malformed. E.g., the identifier is "x-dictionary";key=c and the value of the x-dictionary header field is a=1, b=2 * The identifier is a List Prefix member identifier that specifies more List members than are present the header field. E.g., the identifier is "x-list";prefix=3 and the value of the x-list header field is (1, 2).¶

For the non-normative example Signature metadata in Table 6, the corresponding Signature Input is:¶

# NOTE: '\' line wrapping per RFC 8792
"@request-target": get /foo
"host": example.org
"date": Tue, 07 Jun 2014 20:51:35 GMT
"cache-control": max-age=60, must-revalidate
"x-emptyheader":
"x-example": Example header with some whitespace.
"x-dictionary";key=b: 2
"x-dictionary";key=a: 1
"x-list";prefix=3: (a, b, c)
"@signature-params": ("@request-target" "host" "date" "cache-control" \
  "x-empty-header" "x-example" "x-dictionary";key=b \
  "x-dictionary";key=a "x-list";prefix=3); keyid="test-key-a"; \
  created=1402170695; expires=1402170995

3.1. Creating a Signature

In order to create a signature, a signer completes the following process:¶

1. The signer chooses an HTTP signature algorithm and key material for signing. The signer MUST choose key material that is appropriate for the signature's algorithm, and that conforms to any requirements defined by the algorithm, such as key size or format. The mechanism by which the signer chooses the algorithm and key material is out of scope for this document.¶
2. The signer sets the signature's creation time to the current time.¶
3. If applicable, the signer sets the signature's expiration time property to the time at which the signature is to expire.¶

4. The signer creates an ordered list of content identifiers representing the message content and signature metadata to be covered by the signature, and assigns this list as the signature's Covered Content.¶

   • Each covered content identifier MUST reference either an HTTP header or a specialty content field listed in Section 2.4 or its associated registry.¶
   • Signers SHOULD include @request-target in the covered content list list.¶
   • Signers SHOULD include a date stamp in some form, such as using the date header. Alternatively, the created signature metadata parameter can fulfil this role.¶
   • Further guidance on what to include in this list and in what order is out of scope for this document. However, note that the list order is significant and once established for a given signature it MUST be preserved for that signature.¶
   • Note that the @signature-params specialty identifier is not explicitly listed in the list of covered content identifiers, because it is required to always be present as the last line in the signature input. This ensures that a signature always covers its own metadata.¶
5. The signer creates the signature input string. Section 2.5¶
6. The signer signs the signature input with the chosen signing algorithm using the key material chosen by the signer. Several signing algorithms are defined in in Section 3.3.¶
7. The signer then encodes the result of that operation as a Base64-encoded string [RFC4648]. This string is the signature output value.¶

For example, given the following HTTP message:¶

GET /foo HTTP/1.1
Host: example.org
Date: Sat, 07 Jun 2014 20:51:35 GMT
X-Example: Example header
        with some whitespace.
X-EmptyHeader:
X-Dictionary: a=1, b=2
X-List: (a b c d)
Cache-Control: max-age=60
Cache-Control: must-revalidate

The following table presents a non-normative example of metadata values that a signer may choose:¶

For the non-normative example signature metadata and signature input in Figure 1, the corresponding signature value is:¶

# NOTE: '\' line wrapping per RFC 8792
K2qGT5srn2OGbOIDzQ6kYT+ruaycnDAAUpKv+ePFfD0RAxn/1BUeZx/Kdrq32DrfakQ6b\
PsvB9aqZqognNT6be4olHROIkeV879RrsrObury8L9SCEibeoHyqU/yCjphSmEdd7WD+z\
rchK57quskKwRefy2iEC5S2uAH0EPyOZKWlvbKmKu5q4CaB8X/I5/+HLZLGvDiezqi6/7\
p2Gngf5hwZ0lSdy39vyNMaaAT0tKo6nuVw0S1MVg1Q7MpWYZs0soHjttq0uLIA3DIbQfL\
iIvK6/l0BdWTU7+2uQj7lBkQAsFZHoA96ZZgFquQrXRlmYOh+Hx5D9fJkXcXe5tmAg==

3.2. Verifying a Signature

In order to verify a signature, a verifier MUST follow the following algorithm:¶

1. Examine the signature's parameters to confirm that the signature meets the requirements described in this document, as well as any additional requirements defined by the application such as which contents are required to be covered by the signature. Section 3.2.1¶
2. Determine the verification key material for this signature. If the key material is known through external means such as static configuration or external protocol negotiation, the verifier will use that. If the key is identified in the signature parameters, the verifier will dereference this to appropriate key material to use with the signature. The verifier has to determine the trustworthiness of the key material for the context in which the signature is presented.¶

3. Determine the algorithm to apply for verification:¶

   1. If the algorithm is known through external means such as static configuration or external protocol negotiation, the verifier will use this algorithm.¶
   2. If the algorithm is explicitly stated in the signature parameters using a value from the HTTP Message Signatures registry, the verifier will use the referenced algorithm.¶
   3. If the algorithm can be determined from the keying material, such as through an algorithm field on the key value itself, the verifier will use this algorithm.¶
4. Use the received HTTP message and the signature's metadata to recreate the signature input, using the process described in Section 2.5. The value of the @signature-params input is the value of the SignatureInput header field for this signature serialized according to the rules described in Section 2.4.2, not including the signature's label from the SignatureInput header.¶
5. If the key material is appropriate for the algorithm, apply the verification algorithm to the signature, signature input, signature parameters, key material, and algorithm. The results of the verification algorithm function are the final results of the signature verification. Several algorithms are defined in Section 3.3.¶

If any of the above steps fail, the signature validation fails.¶

3.3. Signature Algorithm Methods

HTTP Message signatures MAY use any cryptographic digital signature or MAC method that allows for the signing of the signature input string. This section contains several common algorithm parameters that can be communicated through the algorithm signature parameter defined in Section 2.4.2, by reference to the key material, or through agreement between the signer and verifier.¶

Signatures are generated from and verified against the byte values of the signature input string defined in Section 2.5.¶

4.1. The 'Signature-Input' HTTP Header

The Signature-Input HTTP header field is a Dictionary Structured Header [RFC8941] containing the metadata for zero or more message signatures generated from content within the HTTP message. Each member describes a single message signature. The member's name is an identifier that uniquely identifies the message signature within the context of the HTTP message. The member's value is the serialization of the covered content including all signature metadata parameters, using the serialization process defined in Section 2.4.2.¶

# NOTE: '\' line wrapping per RFC 8792
Signature-Input: sig1=("@request-target" "host" "date"
    "cache-control" "x-empty-header" "x-example"); keyid="test-key-a";
    alg="rsa-pss-sha512"; created=1402170695; expires=1402170995

To facilitate signature validation, the Signature-Input header MUST contain the same serialization value used in generating the signature input.¶

4.2. The 'Signature' HTTP Header

The Signature HTTP header field is a Dictionary Structured Header [RFC8941] containing zero or more message signatures generated from content within the HTTP message. Each member's name is a signature identifier that is present as a member name in the Signature-Input Structured Header within the HTTP message. Each member's value is a Byte Sequence containing the signature value for the message signature identified by the member name. Any member in the Signature HTTP header field that does not have a corresponding member in the HTTP message's Signature-Input HTTP header field MUST be ignored.¶

# NOTE: '\' line wrapping per RFC 8792
Signature: sig1=:K2qGT5srn2OGbOIDzQ6kYT+ruaycnDAAUpKv+ePFfD0RAxn/1BUe\
    Zx/Kdrq32DrfakQ6bPsvB9aqZqognNT6be4olHROIkeV879RrsrObury8L9SCEibe\
    oHyqU/yCjphSmEdd7WD+zrchK57quskKwRefy2iEC5S2uAH0EPyOZKWlvbKmKu5q4\
    CaB8X/I5/+HLZLGvDiezqi6/7p2Gngf5hwZ0lSdy39vyNMaaAT0tKo6nuVw0S1MVg\
    1Q7MpWYZs0soHjttq0uLIA3DIbQfLiIvK6/l0BdWTU7+2uQj7lBkQAsFZHoA96ZZg\
    FquQrXRlmYOh+Hx5D9fJkXcXe5tmAg==:

4.3. Examples

The following is a non-normative example of Signature-Input and Signature HTTP header fields representing the signature in Figure 2:¶

# NOTE: '\' line wrapping per RFC 8792

Signature-Input: sig1=("@request-target" "host" "date"
    "cache-control" "x-empty-header" "x-example"); keyid="test-key-a";
    alg="rsa-pss-sha512"; created=1402170695; expires=1402170995
Signature: sig1=:K2qGT5srn2OGbOIDzQ6kYT+ruaycnDAAUpKv+ePFfD0RAxn/1BUe\
    Zx/Kdrq32DrfakQ6bPsvB9aqZqognNT6be4olHROIkeV879RrsrObury8L9SCEibe\
    oHyqU/yCjphSmEdd7WD+zrchK57quskKwRefy2iEC5S2uAH0EPyOZKWlvbKmKu5q4\
    CaB8X/I5/+HLZLGvDiezqi6/7p2Gngf5hwZ0lSdy39vyNMaaAT0tKo6nuVw0S1MVg\
    1Q7MpWYZs0soHjttq0uLIA3DIbQfLiIvK6/l0BdWTU7+2uQj7lBkQAsFZHoA96ZZg\
    FquQrXRlmYOh+Hx5D9fJkXcXe5tmAg==:

Since Signature-Input and Signature are both defined as Dictionary Structured Headers, they can be used to easily include multiple signatures within the same HTTP message. For example, a signer may include multiple signatures signing the same content with different keys and/or algorithms to support verifiers with different capabilities, or a reverse proxy may include information about the client in header fields when forwarding the request to a service host, and may also include a signature over those fields and the client's signature. The following is a non-normative example of header fields a reverse proxy might add to a forwarded request that contains the signature in the above example:¶

# NOTE: '\' line wrapping per RFC 8792

X-Forwarded-For: 192.0.2.123
Signature-Input: reverse_proxy_sig=("host" "date"
    "signature";key=sig1 "x-forwarded-for"); keyid="test-key-a";
    alg="rsa-pss-sha512"; created=1402170695; expires=1402170695
Signature: reverse_proxy_sig=:ON3HsnvuoTlX41xfcGWaOEVo1M3bJDRBOp0Pc/O\
    jAOWKQn0VMY0SvMMWXS7xG+xYVa152rRVAo6nMV7FS3rv0rR5MzXL8FCQ2A35DCEN\
    LOhEgj/S1IstEAEFsKmE9Bs7McBsCtJwQ3hMqdtFenkDffSoHOZOInkTYGafkoy78\
    l1VZvmb3Y4yf7McJwAvk2R3gwKRWiiRCw448Nt7JTWzhvEwbh7bN2swc/v3NJbg/w\
    JYyYVbelZx4IywuZnYFxgPl/qvqbAjeEVvaLKLgSMr11y+uzxCHoMnDUnTYhMrmOT\
    4O8lBLfRFOcoJPKBdoKg9U0a96U2mUug1bFOozEVYFg==:

5.1. HTTP Signature Algorithms Registry

This document defines HTTP Signature Algorithms, for which IANA is asked to create and maintain a new registry titled "HTTP Signature Algorithms". Initial values for this registry are given in Section 5.1.2. Future assignments and modifications to existing assignment are to be made through the Expert Review registration policy [RFC8126] and shall follow the template presented in Section 5.1.1.¶

5.2. HTTP Signature Metadata Parameters Registry

This document defines the Signature-Input Structured Header, whose member values may have parameters containing metadata about a message signature. IANA is asked to create and maintain a new registry titled "HTTP Signature Metadata Parameters" to record and maintain the set of parameters defined for use with member values in the Signature-Input Structured Header. Initial values for this registry are given in Section 5.2.2. Future assignments and modifications to existing assignments are to be made through the Expert Review registration policy [RFC8126] and shall follow the template presented in Section 5.2.1.¶

5.3. HTTP Signature Specialty Content Identifiers Registry

This document defines a method for canonicalizing HTTP message content, including content that can be generated from the context of the HTTP message outside of the HTTP headers. This content is identified by a unique key. IANA is asked to create and maintain a new registry typed "HTTP Signature Specialty Content Identifiers" to record and maintain the set of non-header content identifiers and their canonicalization method. Initial values for this registry are given in Section 5.3.2. Future assignments and modifications to existing assignments are to be made through the Expert Review registration policy [RFC8126] and shall follow the template presented in Section 5.3.1.¶

B.1. Example Keys

This section provides cryptographic keys that are referenced in example signatures throughout this document. These keys MUST NOT be used for any purpose other than testing.¶

-----BEGIN RSA PUBLIC KEY-----
MIIBCgKCAQEAhAKYdtoeoy8zcAcR874L8cnZxKzAGwd7v36APp7Pv6Q2jdsPBRrw
WEBnez6d0UDKDwGbc6nxfEXAy5mbhgajzrw3MOEt8uA5txSKobBpKDeBLOsdJKFq
MGmXCQvEG7YemcxDTRPxAleIAgYYRjTSd/QBwVW9OwNFhekro3RtlinV0a75jfZg
kne/YiktSvLG34lw2zqXBDTC5NHROUqGTlML4PlNZS5Ri2U4aCNx2rUPRcKIlE0P
uKxI4T+HIaFpv8+rdV6eUgOrB2xeI1dSFFn/nnv5OoZJEIB+VmuKn3DCUcCZSFlQ
PSXSfBDiUGhwOw76WuSSsf1D4b/vLoJ10wIDAQAB
-----END RSA PUBLIC KEY-----

-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----

B.2. Example keyid Values

The table below maps example keyid values to associated algorithms and/or keys. These are example mappings that are valid only within the context of examples in examples within this and future documents that reference this section. Unless otherwise specified, within the context of examples it should be assumed that the signer and verifier understand these keyid mappings. These keyid values are not reserved, and deployments are free to use them, with these associations or others.¶

B.3. Test Cases

This section provides non-normative examples that may be used as test cases to validate implementation correctness. These examples are based on the following HTTP message:¶

POST /foo?param=value&pet=dog HTTP/1.1
Host: example.com
Date: Tue, 07 Jun 2014 20:51:35 GMT
Content-Type: application/json
Digest: SHA-256=X48E9qOokqqrvdts8nOJRJN3OWDUoyWxBf7kbu9DBPE=
Content-Length: 18

{"hello": "world"}

# NOTE: '\' line wrapping per RFC 8792

Signature: sig1=("date"); alg="rsa-pss-sha512"; keyid="test-key-b"
Signature: sig1=:HtXycCl97RBVkZi66ADKnC9c5eSSlb57GnQ4KFqNZplOpNfxqk62\
    JzZ484jXgLvoOTRaKfR4hwyxlcyb+BWkVasApQovBSdit9Ml/YmN2IvJDPncrlhPD\
    VDv36Z9/DiSO+RNHD7iLXugdXo1+MGRimW1RmYdenl/ITeb7rjfLZ4b9VNnLFtVWw\
    rjhAiwIqeLjodVImzVc5srrk19HMZNuUejK6I3/MyN3+3U8tIRW4LWzx6ZgGZUaEE\
    P0aBlBkt7Fj0Tt5/P5HNW/Sa/m8smxbOHnwzAJDa10PyjzdIbywlnWIIWtZKPPsoV\
    oKVopUWEU3TNhpWmaVhFrUL/O6SN3w==:

"date": Tue, 07 Jun 2014 20:51:35 GMT
"@signature-params": ("date"); alg="rsa-pss-sha512"; keyid="test-key-b"