Signing HTTP Messages
draft-ietf-httpbis-message-signatures-05
The information below is for an old version of the document.
| Document | Type |
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| Authors | Annabelle Backman , Justin Richer , Manu Sporny | ||
| Last updated | 2021-06-08 (Latest revision 2021-04-21) | ||
| Replaces | draft-richanna-http-message-signatures, draft-cavage-http-signatures | ||
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draft-ietf-httpbis-message-signatures-05
HTTP A. Backman, Ed.
Internet-Draft Amazon
Intended status: Standards Track J. Richer
Expires: 10 December 2021 Bespoke Engineering
M. Sporny
Digital Bazaar
8 June 2021
Signing HTTP Messages
draft-ietf-httpbis-message-signatures-05
Abstract
This document describes a mechanism for creating, encoding, and
verifying digital signatures or message authentication codes over
content within an HTTP message. This mechanism supports use cases
where the full HTTP message may not be known to the signer, and where
the message may be transformed (e.g., by intermediaries) before
reaching the verifier.
Note to Readers
_RFC EDITOR: please remove this section before publication_
Discussion of this draft takes place on the HTTP working group
mailing list (ietf-http-wg@w3.org), which is archived at
https://lists.w3.org/Archives/Public/ietf-http-wg/
(https://lists.w3.org/Archives/Public/ietf-http-wg/).
Working Group information can be found at https://httpwg.org/
(https://httpwg.org/); source code and issues list for this draft can
be found at https://github.com/httpwg/http-extensions/labels/
signatures (https://github.com/httpwg/http-extensions/labels/
signatures).
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 https://datatracker.ietf.org/drafts/current/.
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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 10 December 2021.
Copyright Notice
Copyright (c) 2021 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 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 . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Discussion . . . . . . . . . . . . . . . . . 4
1.2. HTTP Message Transformations . . . . . . . . . . . . . . 5
1.3. Safe Transformations . . . . . . . . . . . . . . . . . . 5
1.4. Conventions and Terminology . . . . . . . . . . . . . . . 6
1.5. Application of HTTP Message Signatures . . . . . . . . . 8
2. HTTP Message Signature Covered Content . . . . . . . . . . . 8
2.1. HTTP Headers . . . . . . . . . . . . . . . . . . . . . . 9
2.1.1. Canonicalized Structured HTTP Headers . . . . . . . . 10
2.1.2. Canonicalization Examples . . . . . . . . . . . . . . 10
2.2. Dictionary Structured Field Members . . . . . . . . . . . 11
2.2.1. Canonicalization Examples . . . . . . . . . . . . . . 11
2.3. Specialty Content Fields . . . . . . . . . . . . . . . . 11
2.3.1. Request Target . . . . . . . . . . . . . . . . . . . 12
2.3.2. Signature Parameters . . . . . . . . . . . . . . . . 13
2.4. Creating the Signature Input String . . . . . . . . . . . 14
3. HTTP Message Signatures . . . . . . . . . . . . . . . . . . . 16
3.1. Creating a Signature . . . . . . . . . . . . . . . . . . 17
3.2. Verifying a Signature . . . . . . . . . . . . . . . . . . 18
3.2.1. Enforcing Application Requirements . . . . . . . . . 20
3.3. Signature Algorithm Methods . . . . . . . . . . . . . . . 21
3.3.1. RSASSA-PSS using SHA-512 . . . . . . . . . . . . . . 21
3.3.2. RSASSA-PKCS1-v1_5 using SHA-256 . . . . . . . . . . . 22
3.3.3. HMAC using SHA-256 . . . . . . . . . . . . . . . . . 22
3.3.4. ECDSA using curve P-256 DSS and SHA-256 . . . . . . . 23
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3.3.5. JSON Web Signature (JWS) algorithms . . . . . . . . . 23
4. Including a Message Signature in a Message . . . . . . . . . 23
4.1. The 'Signature-Input' HTTP Header . . . . . . . . . . . . 24
4.2. The 'Signature' HTTP Header . . . . . . . . . . . . . . . 24
4.3. Multiple Signatures . . . . . . . . . . . . . . . . . . . 25
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26
5.1. HTTP Signature Algorithms Registry . . . . . . . . . . . 26
5.1.1. Registration Template . . . . . . . . . . . . . . . . 26
5.1.2. Initial Contents . . . . . . . . . . . . . . . . . . 27
5.2. HTTP Signature Metadata Parameters Registry . . . . . . . 28
5.2.1. Registration Template . . . . . . . . . . . . . . . . 28
5.2.2. Initial Contents . . . . . . . . . . . . . . . . . . 29
5.3. HTTP Signature Specialty Content Identifiers Registry . . 29
5.3.1. Registration Template . . . . . . . . . . . . . . . . 29
5.3.2. Initial Contents . . . . . . . . . . . . . . . . . . 29
6. Security Considerations . . . . . . . . . . . . . . . . . . . 30
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 30
7.1. Normative References . . . . . . . . . . . . . . . . . . 30
7.2. Informative References . . . . . . . . . . . . . . . . . 31
Appendix A. Detecting HTTP Message Signatures . . . . . . . . . 32
Appendix B. Examples . . . . . . . . . . . . . . . . . . . . . . 32
B.1. Example Keys . . . . . . . . . . . . . . . . . . . . . . 32
B.1.1. Example Key RSA test . . . . . . . . . . . . . . . . 33
B.1.2. Example RSA PSS Key . . . . . . . . . . . . . . . . . 33
B.1.3. Example ECC P-256 Test Key . . . . . . . . . . . . . 34
B.1.4. Example Shared Secret . . . . . . . . . . . . . . . . 35
B.2. Test Cases . . . . . . . . . . . . . . . . . . . . . . . 35
B.2.1. Minimal Signature Header using rsa-pss-sha512 . . . . 36
B.2.2. Header Coverage using rsa-pss-sha512 . . . . . . . . 36
B.2.3. Full Coverage using rsa-pss-sha512 . . . . . . . . . 37
B.2.4. Signing a Response using ecdsa-p256-sha256 . . . . . 37
B.2.5. Signing a Request using hmac-sha256 . . . . . . . . . 38
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 38
Document History . . . . . . . . . . . . . . . . . . . . . . . . 39
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 41
1. Introduction
Message integrity and authenticity are important security properties
that are critical to the secure operation of many HTTP applications.
Application developers typically rely on the transport layer to
provide these properties, by operating their application over [TLS].
However, TLS only guarantees these properties over a single TLS
connection, and the path between client and application may be
composed of multiple independent TLS connections (for example, if the
application is hosted behind a TLS-terminating gateway or if the
client is behind a TLS Inspection appliance). In such cases, TLS
cannot guarantee end-to-end message integrity or authenticity between
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the client and application. Additionally, some operating
environments present obstacles that make it impractical to use TLS,
or to use features necessary to provide message authenticity.
Furthermore, some applications require the binding of an application-
level key to the HTTP message, separate from any TLS certificates in
use. Consequently, while TLS can meet message integrity and
authenticity needs for many HTTP-based applications, it is not a
universal solution.
This document defines a mechanism for providing end-to-end integrity
and authenticity for content within an HTTP message. The mechanism
allows applications to create digital signatures or message
authentication codes (MACs) over only that content within the message
that is meaningful and appropriate for the application. Strict
canonicalization rules ensure that the verifier can verify the
signature even if the message has been transformed in any of the many
ways permitted by HTTP.
The mechanism described in this document consists of three parts:
* A common nomenclature and canonicalization rule set for the
different protocol elements and other content within HTTP
messages.
* Algorithms for generating and verifying signatures over HTTP
message content using this nomenclature and rule set.
* A mechanism for attaching a signature and related metadata to an
HTTP message.
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
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"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 (https://openjdk.java.net/groups/net/httpclient/
intro.html)). 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.
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* 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:
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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.
Covered Content:
An ordered list of content identifiers for headers (Section 2.1)
and specialty content (Section 2.3) that indicates the metadata
and message content that is covered by the signature, not
including the "@signature-params" specialty field itself.
HTTP Signature Algorithm:
A cryptographic algorithm that describes the signing and
verification process for the signature. When expressed
explicitly, the value maps to a string defined in the HTTP
Signature Algorithms Registry defined in this document.
Key Material:
The key material required to create or verify the signature. The
key material is often identified with an explicit key identifier,
allowing the signer to indicate to the verifier which key was
used.
Creation Time:
A timestamp representing the point in time that the signature was
generated, as asserted by the signer.
Expiration Time:
A timestamp representing the point in time at which the signature
expires, as asserted by the signer. A signature's expiration time
could be undefined, indicating that the signature does not expire
from the perspective of the signer.
The term "Unix time" is defined by [POSIX.1], Section 4.16
(http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/
V1_chap04.html#tag_04_16).
This document contains non-normative examples of partial and complete
HTTP messages. Some examples use a single trailing backslash '' to
indicate line wrapping for long values, as per [RFC8792]. The "\"
character and leading spaces on wrapped lines are not part of the
value.
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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 2.3.2) 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 2.3.2) 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. HTTP Message Signature Covered Content
In order to allow signers and verifiers to establish which content is
covered by a signature, this document defines content identifiers for
data items covered by an HTTP Message Signature as well as the means
for combining these canonicalized values into a signature input
string.
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Some content within HTTP messages can undergo transformations that
change the bitwise value without altering meaning of the content (for
example, the merging together of header fields with the same name).
Message content must therefore be canonicalized before it is signed,
to ensure that a signature can be verified despite such intermediary
transformations. This document defines rules for each content
identifier that transform the identifier's associated content into
such a canonical form.
Content identifiers are defined using production grammar defined by
RFC8941, Section 4 [RFC8941]. The content identifier is an "sf-
string" value. The content identifier type MAY define parameters
which are included using the "parameters" rule.
content-identifier = sf-string parameters
Note that this means the value of the identifier itself is encased in
double quotes, with parameters following as a semicolon-separated
list, such as ""cache-control"", ""date"", or ""@signature-params"".
The following sections define content identifier types, their
parameters, their associated content, and their canonicalization
rules. The method for combining content identifiers into the
signature input string is defined in Section 2.4.
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.
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2.1.1. Canonicalized Structured HTTP Headers
If value of the the HTTP header in question is a structured field
([RFC8941]), the content identifier MAY include the "sf" parameter.
If this parameter is included, the HTTP header value MUST be
canonicalized using the rules specified in Section 4 of RFC8941
[RFC8941]. Note that this process will replace any optional
whitespace with a single space.
The resulting string is used as the field value input in Section 2.1.
2.1.2. Canonicalization Examples
This section contains non-normative examples of canonicalized values
for header fields, given the following example HTTP message:
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
The following table shows example canonicalized values for header
fields, given that message:
+=====================+==================================+
| Header Field | Canonicalized Value |
+=====================+==================================+
| "cache-control" | max-age=60, must-revalidate |
+---------------------+----------------------------------+
| "date" | Tue, 07 Jun 2014 20:51:35 GMT |
+---------------------+----------------------------------+
| "server" | www.example.com |
+---------------------+----------------------------------+
| "x-empty-header" | |
+---------------------+----------------------------------+
| "x-obs-fold-header" | Obsolete line folding. |
+---------------------+----------------------------------+
| "x-ows-header" | Leading and trailing whitespace. |
+---------------------+----------------------------------+
Table 1: Non-normative examples of header field
canonicalization.
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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 [RFC8941] on a Dictionary containing only
that member.
2.2.1. Canonicalization Examples
This section contains non-normative examples of canonicalized values
for Dictionary Structured Field Members given the following example
header field, whose value is assumed to be a Dictionary:
X-Dictionary: a=1, b=2;x=1;y=2, c=(a b c)
The following table shows example canonicalized values for different
content identifiers, given that field:
+======================+=====================+
| Content Identifier | Canonicalized Value |
+======================+=====================+
| "x-dictionary";key=a | 1 |
+----------------------+---------------------+
| "x-dictionary";key=b | 2;x=1;y=2 |
+----------------------+---------------------+
| "x-dictionary";key=c | (a, b, c) |
+----------------------+---------------------+
Table 2: Non-normative examples of
Dictionary member canonicalization.
2.3. 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:
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@request-target The target request endpoint. (Section 2.3.1)
@signature-params The signature metadata parameters for this
signature. (Section 2.3.2)
Additional specialty content identifiers MAY be defined and
registered in the HTTP Signatures Specialty Content Identifier
Registry. (Section 5.3)
2.3.1. Request Target
The request target endpoint, consisting of the request method and the
path and query of the effective request URI, is identified by the
"@request-target" identifier.
Its value is canonicalized as follows:
1. Take the lowercased HTTP method of the message.
2. Append a space " ".
3. Append the path and query of the request target of the message,
formatted according to the rules defined for the :path pseudo-
header in [HTTP2], Section 8.1.2.3. The resulting string is the
canonicalized value.
2.3.1.1. Canonicalization Examples
The following table contains non-normative example HTTP messages and
their canonicalized "@request-target" values.
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+=========================+=================+
|HTTP Message | @request-target |
+=========================+=================+
| POST /?param=value HTTP/1.1| post |
| Host: www.example.com | /?param=value |
+-------------------------+-----------------+
| POST /a/b HTTP/1.1 | post /a/b |
| Host: www.example.com | |
+-------------------------+-----------------+
| GET http://www.example.com/a/ HTTP/1.1| get /a/ |
+-------------------------+-----------------+
| GET http://www.example.com HTTP/1.1| get / |
+-------------------------+-----------------+
| CONNECT server.example.com:80 HTTP/1.1| connect / |
| Host: server.example.com| |
+-------------------------+-----------------+
| OPTIONS * HTTP/1.1 | options * |
| Host: server.example.com| |
+-------------------------+-----------------+
Table 3: Non-normative examples of "@request-target"
canonicalization.
2.3.2. Signature Parameters
HTTP Message Signatures have metadata properties that provide
information regarding the signature's generation and/or verification.
The signature parameters specialty content is identified by the
"@signature-params" identifier.
Its canonicalized value is the serialization of the signature
parameters for this signature, including the covered content list
with all associated parameters.
* "alg": The HTTP message signature algorithm from the HTTP Message
Signature Algorithm Registry, as an "sf-string" value.
* "keyid": The identifier for the key material as an "sf-string"
value.
* "created": Creation time as an "sf-integer" UNIX timestamp value.
Sub-second precision is not supported.
* "expires": Expiration time as an "sf-integer" UNIX timestamp
value. Sub-second precision is not supported.
* "nonce": A random unique value generated for this signature.
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Additional parameters can be defined in the HTTP Signature Parameters
Registry (Section 5.2.2).
The signature parameters are serialized using the rules in Section 4
of RFC8941 [RFC8941] as follows:
1. Let the output be an empty string.
2. Determine an order for the content identifiers of the covered
content. Once this order is chosen, it cannot be changed.
3. Serialize the content identifiers of the covered content,
including all parameters, as an ordered "inner-list" according to
Section 4.1.1.1 of RFC8941 [RFC8941] and append this to the
output.
4. Determine an order for any signature parameters. Once this order
is chosen, it cannot be changed.
5. Append the parameters to the "inner-list" in the chosen order
according to Section 4.1.1.2 of RFC8941 [RFC8941], skipping
parameters that are not available or not used for this signature.
6. The output contains the signature parameters value.
Note that the "inner-list" serialization is used for the covered
content value instead of the "sf-list" serialization in order to
facilitate this value's additional inclusion in the "Signature-Input"
header's dictionary, as discussed in Section 4.1.
This example shows a canonicalized value for the parameters of a
given signature:
("@request-target" "host" "date" "cache-control" "x-empty-header" \
"x-example");keyid="test-key-rsa-pss";alg="rsa-pss-sha512";\
created=1618884475;expires=1618884775
Note that an HTTP message could contain multiple signatures, but only
the signature parameters used for the current signature are included
in this field.
2.4. 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:
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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 2.3)
5. Append a single newline ""\\n""
3. Append the signature parameters (Section 2.3.2) 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 2.3.2
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.
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* 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"
In the following non-normative example, the HTTP message being signed
is the following request:
GET /foo HTTP/1.1
Host: example.org
Date: Tue, 20 Apr 2021 02:07:55 GMT
X-Example: Example header
with some whitespace.
X-Empty-Header:
Cache-Control: max-age=60
Cache-Control: must-revalidate
The covered content consists of the "@request-target" specialty
content followed by the "Host", "Date", "Cache-Control", "X-Empty-
Header", "X-Example" HTTP headers, in order. The signature creation
timestamp is "1618884475" and the key identifier is "test-key-rsa-
pss". The signature input string for this message with these
parameters is:
"@request-target": get /foo
"host": example.org
"date": Tue, 20 Apr 2021 02:07:55 GMT
"cache-control": max-age=60, must-revalidate
"x-empty-header":
"x-example": Example header with some whitespace.
"@signature-params": ("@request-target" "host" "date" "cache-control" \
"x-empty-header" "x-example");created=1618884475;\
keyid="test-key-rsa-pss"
Figure 1: Non-normative example Signature Input
3. HTTP Message Signatures
An HTTP Message Signature is a signature over a string generated from
a subset of the content in an HTTP message and metadata about the
signature itself. When successfully verified against an HTTP
message, it provides cryptographic proof that with respect to the
subset of content that was signed, the message is semantically
equivalent to the message for which the signature was generated.
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3.1. Creating a Signature
In order to create a signature, a signer MUST follow the following
algorithm:
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.
* Once an order of covered content is chosen, the order MUST NOT
change for the life of the signature.
* Each covered content identifier MUST either reference an HTTP
header in the request message Section 2.1 or reference a
specialty content field listed in Section 2.3 or its
associated registry.
* Signers SHOULD include "@request-target" in the covered
content 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.
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5. The signer creates the signature input string. (Section 2.4)
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 byte array output of the signature function is the HTTP
message signature output value to be included in the "Signature"
header as defined in Section 4.2.
For example, given the HTTP message and signature parameters in the
example in Section 2.4, the example signature input string when
signed with the "test-key-rsa-pss" key in Appendix B.1.2 gives the
following message signature output value, encoded in Base64:
lPxkxqDEPhgrx1yPaKLO7eJ+oPjSwsQ5NjWNRfYP7Jw0FwnK1k8/GH7g5s2q0VTTKVm\
xyfpUDp/HsDphh5Z7Fa/lvtujHyFe/0EP9z7bnVb7YBZrxV52LGvP8p4APhOYuG4yaH\
z478GsJav9BQYK0B2IOHdLFJe8qwWPJs07J47gPewpNwCt0To/zZ2KPpylGX5UHVgJP\
Uom64KjX43u2OwIvSoPEYk4nuBvLR9yxYAHURaTfLoEDUCtY1FsU1hOfG3jAlcT6ill\
fnyS72PEdSSzw1KsxroMj9IYpFhva77YxmJRk4pCIW0F0Kj0ukl7J4y2aZJHMCYI3g8\
yfqh/wQ==
Figure 2: Non-normative example signature value
3.2. Verifying a Signature
A verifier processes a signature and its associated signature input
parameters in concert with each other.
In order to verify a signature, a verifier MUST follow the following
algorithm:
1. Parse the "Signature" and "Signature-Input" headers and extract
the signatures to be verified.
1. If there is more than one signature value present, determine
which signature should be processed for this request. If an
appropriate signature is not found, produce an error.
2. If the chosen "Signature" value does not have a corresponding
"Signature-Input" value, produce an error.
2. Parse the values of the chosen "Signature-Input" header field to
get the parameters for the signature to be verified.
3. Parse the value of the corresponding "Signature" header field to
get the byte array value of the signature to be verified.
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4. Examine the signature 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)
5. 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. If a key is identified that the verifier
does not know, does not trust for this request, or does not match
something preconfigured, the verification MUST fail.
6. 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. If the algorithm is specified in more that one location, such
as through static configuration and the algorithm signature
parameter, or the algorithm signature parameter and from the
key material itself, the resolved algorithms MUST be the
same. If the algorithms are not the same, the verifier MUST
vail the verification.
7. Use the received HTTP message and the signature's metadata to
recreate the signature input, using the process described in
Section 2.4. 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 2.3.2, not
including the signature's label from the "Signature-Input"
header.
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8. If the key material is appropriate for the algorithm, apply the
verification algorithm to the signature, recalculated signature
input, signature parameters, key material, and algorithm.
Several algorithms are defined in Section 3.3.
9. The results of the verification algorithm function are the final
results of the signature verification.
If any of the above steps fail, the signature validation fails.
3.2.1. Enforcing Application Requirements
The verification requirements specified in this document are intended
as a baseline set of restrictions that are generally applicable to
all use cases. Applications using HTTP Message Signatures MAY impose
requirements above and beyond those specified by this document, as
appropriate for their use case.
Some non-normative examples of additional requirements an application
might define are:
* Requiring a specific set of header fields to be signed (e.g.,
Authorization, Digest).
* Enforcing a maximum signature age.
* Prohibiting the use of certain algorithms, or mandating the use of
an algorithm.
* Requiring keys to be of a certain size (e.g., 2048 bits vs. 1024
bits).
* Enforcing uniqueness of a nonce value.
Application-specific requirements are expected and encouraged. When
an application defines additional requirements, it MUST enforce them
during the signature verification process, and signature verification
MUST fail if the signature does not conform to the application's
requirements.
Applications MUST enforce the requirements defined in this document.
Regardless of use case, applications MUST NOT accept signatures that
do not conform to these requirements.
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3.3. Signature Algorithm Methods
HTTP Message signatures MAY use any cryptographic digital signature
or MAC method that is appropriate for the key material, environment,
and needs of the signer and verifier. All signatures are generated
from and verified against the byte values of the signature input
string defined in Section 2.4.
Each signature algorithm method takes as its input the signature
input string as a set of byte values ("I"), the signing key material
("Ks"), and outputs the signed content as a set of byte values ("S"):
HTTP_SIGN (I, Ks) -> S
Each verification algorithm method takes as its input the
recalculated signature input string as a set of byte values ("I"),
the verification key material ("Kv"), and the presented signature to
be verified as a set of byte values ("S") and outputs the
verification result ("V") as a boolean:
HTTP_VERIFY (I, Kv, S) -> V
This section contains several common algorithm methods. The method
to use can be communicated through the algorithm signature parameter
defined in Section 2.3.2, by reference to the key material, or
through mutual agreement between the signer and verifier.
3.3.1. RSASSA-PSS using SHA-512
To sign using this algorithm, the signer applies the "RSASSA-PSS-SIGN
(K, M)" function [RFC8017] with the signer's private signing key
("K") and the signature input string ("M") (Section 2.4). The mask
generation function is "MGF1" as specified in [RFC8017] with a hash
function of SHA-512 [RFC6234]. The salt length ("sLen") is 64 bytes.
The hash function ("Hash") SHA-512 [RFC6234] is applied to the
signature input string to create the digest content to which the
digital signature is applied. The resulting signed content byte
array ("S") is the HTTP message signature output used in Section 3.1.
To verify using this algorithm, the verifier applies the "RSASSA-PSS-
VERIFY ((n, e), M, S)" function [RFC8017] using the public key
portion of the verification key material ("(n, e)") and the signature
input string ("M") re-created as described in Section 3.2. The mask
generation function is "MGF1" as specified in [RFC8017] with a hash
function of SHA-512 [RFC6234]. The salt length ("sLen") is 64 bytes.
The hash function ("Hash") SHA-512 [RFC6234] is applied to the
signature input string to create the digest content to which the
verification function is applied. The verifier extracts the HTTP
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message signature to be verified ("S") as described in Section 3.2.
The results of the verification function are compared to the http
message signature to determine if the signature presented is valid.
3.3.2. RSASSA-PKCS1-v1_5 using SHA-256
To sign using this algorithm, the signer applies the "RSASSA-
PKCS1-V1_5-SIGN (K, M)" function [RFC8017] with the signer's private
signing key ("K") and the signature input string ("M") (Section 2.4).
The hash SHA-256 [RFC6234] is applied to the signature input string
to create the digest content to which the digital signature is
applied. The resulting signed content byte array ("S") is the HTTP
message signature output used in Section 3.1.
To verify using this algorithm, the verifier applies the "RSASSA-
PKCS1-V1_5-VERIFY ((n, e), M, S)" function [RFC8017] using the public
key portion of the verification key material ("(n, e)") and the
signature input string ("M") re-created as described in Section 3.2.
The hash function SHA-256 [RFC6234] is applied to the signature input
string to create the digest content to which the verification
function is applied. The verifier extracts the HTTP message
signature to be verified ("S") as described in Section 3.2. The
results of the verification function are compared to the http message
signature to determine if the signature presented is valid.
3.3.3. HMAC using SHA-256
To sign and verify using this algorithm, the signer applies the
"HMAC" function [RFC2104] with the shared signing key ("K") and the
signature input string ("text") (Section 2.4). The hash function
SHA-256 [RFC6234] is applied to the signature input string to create
the digest content to which the HMAC is applied, giving the signature
result.
For signing, the resulting value is the HTTP message signature output
used in Section 3.1.
For verification, the verifier extracts the HTTP message signature to
be verified ("S") as described in Section 3.2. The output of the
HMAC function is compared to the value of the HTTP message signature,
and the results of the comparison determine the validity of the
signature presented.
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3.3.4. ECDSA using curve P-256 DSS and SHA-256
To sign using this algorithm, the signer applies the "ECDSA"
algorithm [FIPS186-4] using curve P-256 with the signer's private
signing key and the signature input string (Section 2.4). The hash
SHA-256 [RFC6234] is applied to the signature input string to create
the digest content to which the digital signature is applied. The
resulting signed content byte array is the HTTP message signature
output used in Section 3.1.
To verify using this algorithm, the verifier applies the "ECDSA"
algorithm [FIPS186-4] using the public key portion of the
verification key material and the signature input string re-created
as described in Section 3.2. The hash function SHA-256 [RFC6234] is
applied to the signature input string to create the digest content to
which the verification function is applied. The verifier extracts
the HTTP message signature to be verified ("S") as described in
Section 3.2. The results of the verification function are compared
to the http message signature to determine if the signature presented
is valid.
3.3.5. JSON Web Signature (JWS) algorithms
If the signing algorithm is a JOSE signing algorithm from the JSON
Web Signature and Encryption Algorithms Registry established by
[RFC7518], the JWS algorithm definition determines the signature and
hashing algorithms to apply for both signing and verification. There
is no use of the explicit "alg" signature parameter when using JOSE
signing algorithms.
For both signing and verification, the HTTP messages signature input
string (Section 2.4) is used as the entire "JWS Signing Input". The
JOSE Header defined in [RFC7517] is not used, and the signature input
string is not first encoded in Base64 before applying the algorithm.
The output of the JWS signature is taken as a byte array prior to the
Base64url encoding used in JOSE.
The JWS algorithm MUST NOT be "none" and MUST NOT be any algorithm
with a JOSE Implementation Requirement of "Prohibited".
4. Including a Message Signature in a Message
Message signatures can be included within an HTTP message via the
"Signature-Input" and "Signature" HTTP header fields, both defined
within this specification.
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An HTTP message signature MUST use both headers: the "Signature" HTTP
header field contains the signature value, while the "Signature-
Input" HTTP header field identifies the covered content and
parameters that describe how the signature was generated. Each
header MAY contain multiple labeled values, where the labels
determine the correlation between the "Signature" and "Signature-
Input" fields.
4.1. The 'Signature-Input' HTTP Header
The "Signature-Input" HTTP header field is a Dictionary Structured
Header [RFC8941] containing the metadata for one 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 2.3.2.
Signature-Input: sig1=("@request-target" "host" "date" \
"cache-control" "x-empty-header" "x-example");created=1618884475\
;keyid="test-key-rsa-pss"
To facilitate signature validation, the "Signature-Input" header
value MUST contain the same serialized value used in generating the
signature input string's "@signature-params" value.
4.2. The 'Signature' HTTP Header
The "Signature" HTTP header field is a Dictionary Structured Header
[RFC8941] containing one 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.
Signature: sig1=:lPxkxqDEPhgrx1yPaKLO7eJ+oPjSwsQ5NjWNRfYP7Jw0FwnK1k\
8/GH7g5s2q0VTTKVmxyfpUDp/HsDphh5Z7Fa/lvtujHyFe/0EP9z7bnVb7YBZrxV5\
2LGvP8p4APhOYuG4yaHz478GsJav9BQYK0B2IOHdLFJe8qwWPJs07J47gPewpNwCt\
0To/zZ2KPpylGX5UHVgJPUom64KjX43u2OwIvSoPEYk4nuBvLR9yxYAHURaTfLoED\
UCtY1FsU1hOfG3jAlcT6illfnyS72PEdSSzw1KsxroMj9IYpFhva77YxmJRk4pCIW\
0F0Kj0ukl7J4y2aZJHMCYI3g8yfqh/wQ==:
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4.3. Multiple Signatures
Since "Signature-Input" and "Signature" are both defined as
Dictionary Structured Headers, they can be used to include multiple
signatures within the same HTTP message. For example, a signer may
include multiple signatures signing the same content with different
keys 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, including a
signature over those fields and the client's original signature.
The following is a non-normative example of header fields a reverse
proxy sets in addition to the examples in the previous sections. The
original signature is included under the identifier "sig1", and the
reverse proxy's signature is included under "proxy_sig". The proxy
uses the key "rsa-test-key" to create its signature using the "rsa-
v1_5-sha256" signature value. This results in a signature input
string of:
"signature";key="sig1": \
:lPxkxqDEPhgrx1yPaKLO7eJ+oPjSwsQ5NjWNRfYP7Jw0FwnK1k8/GH7g5s2q0VTT\
KVmxyfpUDp/HsDphh5Z7Fa/lvtujHyFe/0EP9z7bnVb7YBZrxV52LGvP8p4APhOYu\
G4yaHz478GsJav9BQYK0B2IOHdLFJe8qwWPJs07J47gPewpNwCt0To/zZ2KPpylGX\
5UHVgJPUom64KjX43u2OwIvSoPEYk4nuBvLR9yxYAHURaTfLoEDUCtY1FsU1hOfG3\
jAlcT6illfnyS72PEdSSzw1KsxroMj9IYpFhva77YxmJRk4pCIW0F0Kj0ukl7J4y2\
aZJHMCYI3g8yfqh/wQ==:
"x-forwarded-for": 192.0.2.123
"@signature-params": ("signature";key="sig1" "x-forwarded-for")\
;created=1618884480;keyid="test-key-rsa";alg="rsa-v1_5-sha256"
And a signature output value of:
XD1O/vEh772WVpY7jYvReXop2+b7xTIIPKH8/OCYzPn78Wd9jodCwAJPF5TYCn9L6n6\
8j4EjGsqFOMkVLVdSQEZqMLjEbvMEdIe8m1a0CLd5kydeaAwoHoglqod6ijkwhhEtxt\
aD8tDZmihQw2mZEH8u4aMSnRntqy7ExCNld0JLharsHV0iCbRO9jIP+d2ApD7gB+eZp\
n3pIvvVJZlxTwPkahFpxKlQtNMPaSqa1lvejURx+ST8CEuz4sS+G/oLJiX3MZenuUoO\
R8HeOHDnjN/VLzrEN4x44iF7WIL+iY2PtK87LUWRAsJAX9GqHL/upsGh1nxIdoVaoLV\
V5w+fRw==
These values are added to the HTTP request message by the proxy. The
different signature values are wrapped onto separate lines to
increase human-readability of the result.
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X-Forwarded-For: 192.0.2.123
Signature-Input: sig1=("@request-target" "host" "date" \
"cache-control" "x-empty-header" "x-example")\
;created=1618884475;keyid="test-key-rsa-pss", \
proxy_sig=("signature";key="sig1" "x-forwarded-for")\
;created=1618884480;keyid="test-key-rsa";alg="rsa-v1_5-sha256"
Signature: sig1=:lPxkxqDEPhgrx1yPaKLO7eJ+oPjSwsQ5NjWNRfYP7Jw0FwnK1k\
8/GH7g5s2q0VTTKVmxyfpUDp/HsDphh5Z7Fa/lvtujHyFe/0EP9z7bnVb7YBZrx\
V52LGvP8p4APhOYuG4yaHz478GsJav9BQYK0B2IOHdLFJe8qwWPJs07J47gPewp\
NwCt0To/zZ2KPpylGX5UHVgJPUom64KjX43u2OwIvSoPEYk4nuBvLR9yxYAHURa\
TfLoEDUCtY1FsU1hOfG3jAlcT6illfnyS72PEdSSzw1KsxroMj9IYpFhva77Yxm\
JRk4pCIW0F0Kj0ukl7J4y2aZJHMCYI3g8yfqh/wQ==:, \
proxy_sig=:XD1O/vEh772WVpY7jYvReXop2+b7xTIIPKH8/OCYzPn78Wd9jodCwA\
JPF5TYCn9L6n68j4EjGsqFOMkVLVdSQEZqMLjEbvMEdIe8m1a0CLd5kydeaAwoH\
oglqod6ijkwhhEtxtaD8tDZmihQw2mZEH8u4aMSnRntqy7ExCNld0JLharsHV0i\
CbRO9jIP+d2ApD7gB+eZpn3pIvvVJZlxTwPkahFpxKlQtNMPaSqa1lvejURx+ST\
8CEuz4sS+G/oLJiX3MZenuUoOR8HeOHDnjN/VLzrEN4x44iF7WIL+iY2PtK87LU\
WRAsJAX9GqHL/upsGh1nxIdoVaoLVV5w+fRw==:
The proxy's signature and the client's original signature can be
verified independently for the same message, depending on the needs
of the application.
5. IANA Considerations
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.
Algorithms referenced by algorithm identifiers have to be fully
defined with all parameters fixed. Algorithm identifiers in this
registry are to be interpreted as whole string values and not as a
combination of parts. That is to say, it is expected that
implementors understand "rsa-pss-sha512" as referring to one specific
algorithm with its hash, mask, and salt values set as defined here.
Implementors do not parse out the "rsa", "pss", and "sha512" portions
of the identifier to determine parameters of the signing algorithm
from the string.
5.1.1. Registration Template
Algorithm Name:
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An identifier for the HTTP Signature Algorithm. The name MUST be
an ASCII string consisting only of lower-case characters (""a"" -
""z""), digits (""0"" - ""9""), and hyphens (""-""), and SHOULD
NOT exceed 20 characters in length. The identifier MUST be unique
within the context of the registry.
Status:
A brief text description of the status of the algorithm. The
description MUST begin with one of "Active" or "Deprecated", and
MAY provide further context or explanation as to the reason for
the status.
Description:
A brief description of the algorithm used to sign the signature
input string.
Specification document(s):
Reference to the document(s) that specify the token endpoint
authorization method, preferably including a URI that can be used
to retrieve a copy of the document(s). An indication of the
relevant sections may also be included but is not required.
5.1.2. Initial Contents
5.1.2.1. rsa-pss-sha512
Algorithm Name:
"rsa-pss-sha512"
Status:
Active
Definition:
RSASSA-PSS using SHA-256
Specification document(s):
[[This document]], Section 3.3.1
5.1.2.2. rsa-v1_5-sha256
Algorithm Name:
"rsa-v1_5-sha256"
Status:
Active
Description:
RSASSA-PKCS1-v1_5 using SHA-256
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Specification document(s):
[[This document]], Section 3.3.2
5.1.2.3. hmac-sha256
Algorithm Name:
"hmac-sha256"
Status:
Active
Description:
HMAC using SHA-256
Specification document(s):
[[This document]], Section 3.3.3
5.1.2.4. ecdsa-p256-sha256
Algorithm Name:
"ecdsa-p256-sha256"
Status:
Active
Description:
ECDSA using curve P-256 DSS and SHA-256
Specification document(s):
[[This document]], Section 3.3.4
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.
5.2.1. Registration Template
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5.2.2. Initial Contents
The table below contains the initial contents of the HTTP Signature
Metadata Parameters Registry. Each row in the table represents a
distinct entry in the registry.
+=========+========+================================+
| Name | Status | Reference(s) |
+=========+========+================================+
| alg | Active | Section 2.3.2 of this document |
+---------+--------+--------------------------------+
| created | Active | Section 2.3.2 of this document |
+---------+--------+--------------------------------+
| expires | Active | Section 2.3.2 of this document |
+---------+--------+--------------------------------+
| keyid | Active | Section 2.3.2 of this document |
+---------+--------+--------------------------------+
| nonce | Active | Section 2.3.2 of this document |
+---------+--------+--------------------------------+
Table 4: Initial contents of the HTTP Signature
Metadata Parameters Registry.
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.
5.3.1. Registration Template
5.3.2. Initial Contents
The table below contains the initial contents of the HTTP Signature
Specialty Content Identifiers Registry.
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+===================+========+================================+
| Name | Status | Reference(s) |
+===================+========+================================+
| @request-target | Active | Section 2.3.1 of this document |
+-------------------+--------+--------------------------------+
| @signature-params | Active | Section 2.3.2 of this document |
+-------------------+--------+--------------------------------+
Table 5: Initial contents of the HTTP Signature Specialty
Content Identifiers Registry.
6. Security Considerations
(( TODO: need to dive deeper on this section; not sure how much of
what's referenced below is actually applicable, or if it covers
everything we need to worry about. ))
(( TODO: Should provide some recommendations on how to determine what
content needs to be signed for a given use case. ))
There are a number of security considerations to take into account
when implementing or utilizing this specification. A thorough
security analysis of this protocol, including its strengths and
weaknesses, can be found in [WP-HTTP-Sig-Audit].
7. References
7.1. Normative References
[FIPS186-4]
"Digital Signature Standard (DSS)", 2013,
<https://csrc.nist.gov/publications/detail/fips/186/4/
final>.
[HTTP2] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext
Transfer Protocol Version 2 (HTTP/2)", RFC 7540,
DOI 10.17487/RFC7540, May 2015,
<https://www.rfc-editor.org/rfc/rfc7540>.
[MESSAGING]
Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Message Syntax and Routing",
RFC 7230, DOI 10.17487/RFC7230, June 2014,
<https://www.rfc-editor.org/rfc/rfc7230>.
[POSIX.1] "The Open Group Base Specifications Issue 7, 2018
edition", 2018,
<https://pubs.opengroup.org/onlinepubs/9699919799/>.
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[RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
Hashing for Message Authentication", RFC 2104,
DOI 10.17487/RFC2104, February 1997,
<https://www.rfc-editor.org/rfc/rfc2104>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC8792] Watsen, K., Auerswald, E., Farrel, A., and Q. Wu,
"Handling Long Lines in Content of Internet-Drafts and
RFCs", RFC 8792, DOI 10.17487/RFC8792, June 2020,
<https://www.rfc-editor.org/rfc/rfc8792>.
[RFC8941] Nottingham, M. and P-H. Kamp, "Structured Field Values for
HTTP", RFC 8941, DOI 10.17487/RFC8941, February 2021,
<https://www.rfc-editor.org/rfc/rfc8941>.
[SEMANTICS]
Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
DOI 10.17487/RFC7231, June 2014,
<https://www.rfc-editor.org/rfc/rfc7231>.
7.2. Informative References
[RFC6234] Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms
(SHA and SHA-based HMAC and HKDF)", RFC 6234,
DOI 10.17487/RFC6234, May 2011,
<https://www.rfc-editor.org/rfc/rfc6234>.
[RFC7239] Petersson, A. and M. Nilsson, "Forwarded HTTP Extension",
RFC 7239, DOI 10.17487/RFC7239, June 2014,
<https://www.rfc-editor.org/rfc/rfc7239>.
[RFC7517] Jones, M., "JSON Web Key (JWK)", RFC 7517,
DOI 10.17487/RFC7517, May 2015,
<https://www.rfc-editor.org/rfc/rfc7517>.
[RFC7518] Jones, M., "JSON Web Algorithms (JWA)", RFC 7518,
DOI 10.17487/RFC7518, May 2015,
<https://www.rfc-editor.org/rfc/rfc7518>.
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[RFC8017] Moriarty, K., Ed., Kaliski, B., Jonsson, J., and A. Rusch,
"PKCS #1: RSA Cryptography Specifications Version 2.2",
RFC 8017, DOI 10.17487/RFC8017, November 2016,
<https://www.rfc-editor.org/rfc/rfc8017>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/rfc/rfc8126>.
[TLS] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/rfc/rfc8446>.
[WP-HTTP-Sig-Audit]
"Security Considerations for HTTP Signatures", 2013,
<https://web-payments.org/specs/source/http-signatures-
audit/>.
Appendix A. Detecting HTTP Message Signatures
There have been many attempts to create signed HTTP messages in the
past, including other non-standard definitions of the "Signature"
header used within this specification. It is recommended that
developers wishing to support both this specification and other
historical drafts do so carefully and deliberately, as
incompatibilities between this specification and various versions of
other drafts could lead to unexpected problems.
It is recommended that implementers first detect and validate the
"Signature-Input" header defined in this specification to detect that
this standard is in use and not an alternative. If the "Signature-
Input" header is present, all "Signature" headers can be parsed and
interpreted in the context of this draft.
Appendix B. Examples
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.
The key identifiers for each key are used throughout the examples in
this specification. It is assumed for these examples that the signer
and verifier can unambiguously dereference all key identifiers used
here, and that the keys and algorithms used are appropriate for the
context in which the signature is presented.
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B.1.1. Example Key RSA test
The following key is a 2048-bit RSA public and private key pair,
referred to in this document as "test-key-rsa":
-----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.1.2. Example RSA PSS Key
The following key is a 2048-bit RSA public and private key pair,
referred to in this document as "test-key-rsa-pss":
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-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAr4tmm3r20Wd/PbqvP1s2
+QEtvpuRaV8Yq40gjUR8y2Rjxa6dpG2GXHbPfvMs8ct+Lh1GH45x28Rw3Ry53mm+
oAXjyQ86OnDkZ5N8lYbggD4O3w6M6pAvLkhk95AndTrifbIFPNU8PPMO7OyrFAHq
gDsznjPFmTOtCEcN2Z1FpWgchwuYLPL+Wokqltd11nqqzi+bJ9cvSKADYdUAAN5W
Utzdpiy6LbTgSxP7ociU4Tn0g5I6aDZJ7A8Lzo0KSyZYoA485mqcO0GVAdVw9lq4
aOT9v6d+nb4bnNkQVklLQ3fVAvJm+xdDOp9LCNCN48V2pnDOkFV6+U9nV5oyc6XI
2wIDAQAB
-----END PUBLIC KEY-----
-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----
B.1.3. Example ECC P-256 Test Key
The following key is an elliptical curve key over the curve P-256,
referred to in this document as "test-key-ecc-p256".
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-----BEGIN EC PRIVATE KEY-----
MHcCAQEEIFKbhfNZfpDsW43+0+JjUr9K+bTeuxopu653+hBaXGA7oAoGCCqGSM49
AwEHoUQDQgAEqIVYZVLCrPZHGHjP17CTW0/+D9Lfw0EkjqF7xB4FivAxzic30tMM
4GF+hR6Dxh71Z50VGGdldkkDXZCnTNnoXQ==
-----END EC PRIVATE KEY-----
-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEqIVYZVLCrPZHGHjP17CTW0/+D9Lf
w0EkjqF7xB4FivAxzic30tMM4GF+hR6Dxh71Z50VGGdldkkDXZCnTNnoXQ==
-----END PUBLIC KEY-----
B.1.4. Example Shared Secret
The following shared secret is 64 randomly-generated bytes encoded in
Base64, referred to in this document as "test-shared-secret".
uzvJfB4u3N0Jy4T7NZ75MDVcr8zSTInedJtkgcu46YW4XByzNJjxBdtjUkdJPBt\
bmHhIDi6pcl8jsasjlTMtDQ==
B.2. 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 messages:
For requests, this "test-request" message is used:
POST /foo?param=value&pet=dog HTTP/1.1
Host: example.com
Date: Tue, 20 Apr 2021 02:07:55 GMT
Content-Type: application/json
Digest: SHA-256=X48E9qOokqqrvdts8nOJRJN3OWDUoyWxBf7kbu9DBPE=
Content-Length: 18
{"hello": "world"}
For responses, this "test-response" message is used:
HTTP/1.1 200 OK
Date: Tue, 20 Apr 2021 02:07:56 GMT
Content-Type: application/json
Digest: SHA-256=X48E9qOokqqrvdts8nOJRJN3OWDUoyWxBf7kbu9DBPE=
Content-Length: 18
{"hello": "world"}
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B.2.1. Minimal Signature Header using rsa-pss-sha512
This example presents a minimal "Signature-Input" and "Signature"
header for a signature using the "rsa-pss-sha512" algorithm over
"test-request", covering none of the content of the HTTP message
request but providing a timestamped signature proof of possession of
the key.
The corresponding signature input is:
"@signature-params": ();created=1618884475\
;keyid="test-key-rsa-pss";alg="rsa-pss-sha512"
This results in the following "Signature-Input" and "Signature"
headers being added to the message:
Signature-Input: sig1=();created=1618884475\
;keyid="test-key-rsa-pss";alg="rsa-pss-sha512"
Signature: sig1=:VrfdC2KEFFLoGMYTbQz4PSlKat4hAxcr5XkVN7Mm/7OQQJG+uX\
gOez7kA6n/yTCaR1VL+FmJd2IVFCsUfcc/jO9siZK3siadoK1Dfgp2ieh9eO781ty\
SS70OwvAkdORuQLWDnaDMRDlQhg5sNP6JaQghFLqD4qgFrM9HMPxLrznhAQugJ0Fd\
RZLtSpnjECW6qsu2PVRoCYfnwe4gu8TfqH5GDx2SkpCF9BQ8CijuIWlOg7QP73tKt\
QNp65u14Si9VEVXHWGiLw4blyPLzWz/fqJbdLaq94Ep60Nq8WjYEAInYH6KyV7EAD\
60LXdspwF50R3dkWXJP/x+gkAHSMsxbg==:
B.2.2. Header Coverage using rsa-pss-sha512
This example covers all the specified headers in "test-request"
except for the body digest header using the "rsa-pss-sha512"
algorithm.
The corresponding signature input is:
"host": example.com
"date": Tue, 20 Apr 2021 02:07:55 GMT
"content-type": application/json
"@signature-params": ("host" "date" "content-type")\
;created=1618884475;keyid="test-key-rsa-pss"
This results in the following "Signature-Input" and "Signature"
headers being added to the message:
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Signature-Input: sig1=("host" "date" "content-type")\
;created=1618884475;keyid="test-key-rsa-pss"
Signature: sig1=:Zu48JBrHlXN+hVj3T5fPQUjMNEEhABM5vNmiWuUUl7BWNid5Rz\
OH1tEjVi+jObYkYT8p09lZ2hrNuU3xm+JUBT8WNIlopJtt0EzxFnjGlHvkhu3KbJf\
xNlvCJVlOEdR4AivDLMeK/ZgASpZ7py1UNHJqRyGCYkYpeedinXUertL/ySNp+VbK\
2O/qCoui2jFgff2kXQd6rjL1Up83Fpr+/KoZ6HQkv3qwBdMBDyHQykfZHhLn4AO1I\
G+vKhOLJQDfaLsJ/fYfzsgc1s46j3GpPPD/W2nEEtdhNwu7oXq81qVRsENChIu1XI\
FKR9q7WpyHDKEWTtaNZDS8TFvIQRU22w==:
B.2.3. Full Coverage using rsa-pss-sha512
This example covers all headers in "test-request" plus the request
target and message body digest using the "rsa-pss-sha512" algorithm.
The corresponding signature input is:
"@request-target": post /foo?param=value&pet=dog
"host": example.com
"date": Tue, 20 Apr 2021 02:07:55 GMT
"content-type": application/json
"digest": SHA-256=X48E9qOokqqrvdts8nOJRJN3OWDUoyWxBf7kbu9DBPE=
"content-length": 18
"@signature-params": ("@request-target" "host" "date" \
"content-type" "digest" "content-length");created=1618884475\
;keyid="test-key-rsa-pss"
This results in the following "Signature-Input" and "Signature"
headers being added to the message:
Signature-Input: sig1=("@request-target" "host" "date" \
"content-type" "digest" "content-length");created=1618884475\
;keyid="test-key-rsa-pss"
Signature: \
sig1=:iD5NhkJoGSuuTpWMzS0BI47DfbWwsGmHHLTwOxT0n+0cQFSC+1c26B7IOfI\
RTYofqD0sfYYrnSwCvWJfA1zthAEv9J1CxS/CZXe7CQvFpuKuFJxMpkAzVYdE/TA6\
fELxNZy9RJEWZUPBU4+aJ26d8PC0XhPObXe6JkP6/C7XvG2QinsDde7rduMdhFN/H\
j2MuX1Ipzvv4EgbHJdKwmWRNamfmKJZC4U5Tn0F58lzGF+WIpU73V67/6aSGvJGM5\
7U9bRHrBB7ExuQhOX2J2dvJMYkE33pEJA70XBUp9ZvciTI+vjIUgUQ2oRww3huWML\
mMMqEc95CliwIoL5aBdCnlQ==:
B.2.4. Signing a Response using ecdsa-p256-sha256
This example covers portions of the "test-response" response message
using the "ecdsa-p256-sha256" algorithm and the key "test-key-ecc-
p256".
The corresponding signature input is:
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"date": Tue, 20 Apr 2021 02:07:56 GMT
"content-type": application/json
"digest": SHA-256=X48E9qOokqqrvdts8nOJRJN3OWDUoyWxBf7kbu9DBPE=
"content-length": 18
"@signature-params": ("date" "content-type" "digest" \
"content-length");created=1618884475;keyid="test-key-ecc-p256"
This results in the following "Signature-Input" and "Signature"
headers being added to the message:
Signature-Input: sig1=("date" "content-type" "digest" \
"content-length");created=1618884475;keyid="test-key-ecc-p256"
Signature: \
sig1=:3zmRDW6r50/RETqqhtx/N5sdd5eTh8xmHdsrYRK9wK4rCNEwLjCOBlcQxTL\
2oJTCWGRkuqE2r9KyqZFY9jd+NQ==:
B.2.5. Signing a Request using hmac-sha256
This example covers portions of the "test-request" using the "hmac-
sha256" algorithm and the secret "test-shared-secret".
The corresponding signature input is:
"host": example.com
"date": Tue, 20 Apr 2021 02:07:55 GMT
"content-type": application/json
"@signature-params": ("host" "date" "content-type")\
;created=1618884475;keyid="test-shared-secret"
This results in the following "Signature-Input" and "Signature"
headers being added to the message:
Signature-Input: sig1=("host" "date" "content-type")\
;created=1618884475;keyid="test-shared-secret"
Signature: sig1=:x54VEvVOb0TMw8fUbsWdUHqqqOre+K7sB/LqHQvnfaQ=:
Acknowledgements
This specification was initially based on the draft-cavage-http-
signatures internet draft. The editors would like to thank the
authors of that draft, Mark Cavage and Manu Sporny, for their work on
that draft and their continuing contributions.
The editors would also like to thank the following individuals for
feedback, insight, and implementation of this draft and its
predecessors (in alphabetical order): Mark Adamcin, Mark Allen, Paul
Annesley, Karl Boehlmark, Stephane Bortzmeyer, Sarven Capadisli, Liam
Dennehy, ductm54, Stephen Farrell, Phillip Hallam-Baker, Eric Holmes,
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Andrey Kislyuk, Adam Knight, Dave Lehn, Dave Longley, Ilari
Liusvaara, James H. Manger, Kathleen Moriarty, Mark Nottingham, Yoav
Nir, Adrian Palmer, Lucas Pardue, Roberto Polli, Julian Reschke,
Michael Richardson, Wojciech Rygielski, Adam Scarr, Cory J. Slep,
Dirk Stein, Henry Story, Lukasz Szewc, Chris Webber, and Jeffrey
Yasskin.
Document History
_RFC EDITOR: please remove this section before publication_
* draft-ietf-httpbis-message-signatures
- -05
o Remove list prefixes.
o Clarify signature algorithm parameters.
o Update and fix examples.
o Add examples for ECC and HMAC.
- -04
o Moved signature component definitions up to intro.
o Created formal function definitions for algorithms to
fulfill.
o Updated all examples.
o Added nonce parameter field.
- -03
o Clarified signing and verification processes.
o Updated algorithm and key selection method.
o Clearly defined core algorithm set.
o Defined JOSE signature mapping process.
o Removed legacy signature methods.
o Define signature parameters separately from "signature"
object model.
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o Define serialization values for signature-input header based
on signature input.
- -02
o Removed editorial comments on document sources.
o Removed in-document issues list in favor of tracked issues.
o Replaced unstructured "Signature" header with "Signature-
Input" and "Signature" Dictionary Structured Header Fields.
o Defined content identifiers for individual Dictionary
members, e.g., ""x-dictionary-field";key=member-name".
o Defined content identifiers for first N members of a List,
e.g., ""x-list-field":prefix=4".
o Fixed up examples.
o Updated introduction now that it's adopted.
o Defined specialty content identifiers and a means to extend
them.
o Required signature parameters to be included in signature.
o Added guidance on backwards compatibility, detection, and
use of signature methods.
- -01
o Strengthened requirement for content identifiers for header
fields to be lower-case (changed from SHOULD to MUST).
o Added real example values for Creation Time and Expiration
Time.
o Minor editorial corrections and readability improvements.
- -00
o Initialized from draft-richanna-http-message-signatures-00,
following adoption by the working group.
* draft-richanna-http-message-signatures
- -00
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o Converted to xml2rfc v3 and reformatted to comply with RFC
style guides.
o Removed Signature auth-scheme definition and related
content.
o Removed conflicting normative requirements for use of
algorithm parameter. Now MUST NOT be relied upon.
o Removed Extensions appendix.
o Rewrote abstract and introduction to explain context and
need, and challenges inherent in signing HTTP messages.
o Rewrote and heavily expanded algorithm definition, retaining
normative requirements.
o Added definitions for key terms, referenced RFC 7230 for
HTTP terms.
o Added examples for canonicalization and signature generation
steps.
o Rewrote Signature header definition, retaining normative
requirements.
o Added default values for algorithm and expires parameters.
o Rewrote HTTP Signature Algorithms registry definition.
Added change control policy and registry template. Removed
suggested URI.
o Added IANA HTTP Signature Parameter registry.
o Added additional normative and informative references.
o Added Topics for Working Group Discussion section, to be
removed prior to publication as an RFC.
Authors' Addresses
Annabelle Backman (editor)
Amazon
P.O. Box 81226
Seattle, WA 98108-1226
United States of America
Email: richanna@amazon.com
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URI: https://www.amazon.com/
Justin Richer
Bespoke Engineering
Email: ietf@justin.richer.org
URI: https://bspk.io/
Manu Sporny
Digital Bazaar
203 Roanoke Street W.
Blacksburg, VA 24060
United States of America
Email: msporny@digitalbazaar.com
URI: https://manu.sporny.org/
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