--- 1/draft-ietf-httpbis-message-signatures-05.txt 2021-08-13 11:13:12.607872236 -0700 +++ 2/draft-ietf-httpbis-message-signatures-06.txt 2021-08-13 11:13:12.671873041 -0700 @@ -1,30 +1,32 @@ HTTP A. Backman, Ed. Internet-Draft Amazon Intended status: Standards Track J. Richer -Expires: 10 December 2021 Bespoke Engineering +Expires: 14 February 2022 Bespoke Engineering M. Sporny Digital Bazaar - 8 June 2021 + 13 August 2021 - Signing HTTP Messages - draft-ietf-httpbis-message-signatures-05 + HTTP Message Signatures + draft-ietf-httpbis-message-signatures-06 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 + components of 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. + reaching the verifier. This document also describes a means for + requesting that a signature be applied to a subsequent HTTP message + in an ongoing HTTP exchange. 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/). @@ -42,98 +44,113 @@ 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/. 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. + This Internet-Draft will expire on 14 February 2022. 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. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 + 1.1. Requirements Discussion . . . . . . . . . . . . . . . . . 5 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 - 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 + 1.3. Safe Transformations . . . . . . . . . . . . . . . . . . 6 + 1.4. Conventions and Terminology . . . . . . . . . . . . . . . 7 + 1.5. Application of HTTP Message Signatures . . . . . . . . . 9 + 2. HTTP Message Components . . . . . . . . . . . . . . . . . . . 10 + 2.1. HTTP Fields . . . . . . . . . . . . . . . . . . . . . . . 11 + 2.1.1. Canonicalized Structured HTTP Fields . . . . . . . . 11 + 2.1.2. Canonicalization Examples . . . . . . . . . . . . . . 11 + 2.2. Dictionary Structured Field Members . . . . . . . . . . . 12 + 2.2.1. Canonicalization Examples . . . . . . . . . . . . . . 12 + 2.3. Specialty Components . . . . . . . . . . . . . . . . . . 13 + 2.3.1. Signature Parameters . . . . . . . . . . . . . . . . 14 + 2.3.2. Method . . . . . . . . . . . . . . . . . . . . . . . 15 + 2.3.3. Target URI . . . . . . . . . . . . . . . . . . . . . 16 + 2.3.4. Authority . . . . . . . . . . . . . . . . . . . . . . 16 + 2.3.5. Scheme . . . . . . . . . . . . . . . . . . . . . . . 17 + 2.3.6. Request Target . . . . . . . . . . . . . . . . . . . 17 + 2.3.7. Path . . . . . . . . . . . . . . . . . . . . . . . . 19 + 2.3.8. Query . . . . . . . . . . . . . . . . . . . . . . . . 19 + 2.3.9. Query Parameters . . . . . . . . . . . . . . . . . . 20 + 2.3.10. Status Code . . . . . . . . . . . . . . . . . . . . . 21 + 2.3.11. Request-Response Signature Binding . . . . . . . . . 21 + 2.4. Creating the Signature Input String . . . . . . . . . . . 23 + + 3. HTTP Message Signatures . . . . . . . . . . . . . . . . . . . 25 + 3.1. Creating a Signature . . . . . . . . . . . . . . . . . . 25 + 3.2. Verifying a Signature . . . . . . . . . . . . . . . . . . 27 + 3.2.1. Enforcing Application Requirements . . . . . . . . . 29 + 3.3. Signature Algorithm Methods . . . . . . . . . . . . . . . 29 + 3.3.1. RSASSA-PSS using SHA-512 . . . . . . . . . . . . . . 30 + 3.3.2. RSASSA-PKCS1-v1_5 using SHA-256 . . . . . . . . . . . 31 + 3.3.3. HMAC using SHA-256 . . . . . . . . . . . . . . . . . 31 + 3.3.4. ECDSA using curve P-256 DSS and SHA-256 . . . . . . . 31 + 3.3.5. JSON Web Signature (JWS) algorithms . . . . . . . . . 32 + 4. Including a Message Signature in a Message . . . . . . . . . 32 + 4.1. The 'Signature-Input' HTTP Field . . . . . . . . . . . . 33 + 4.2. The 'Signature' HTTP Field . . . . . . . . . . . . . . . 33 + 4.3. Multiple Signatures . . . . . . . . . . . . . . . . . . . 34 + 5. Requesting Signatures . . . . . . . . . . . . . . . . . . . . 36 + 5.1. The Accept-Signature Field . . . . . . . . . . . . . . . 37 + 5.2. Processing an Accept-Signature . . . . . . . . . . . . . 37 + 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 38 + 6.1. HTTP Signature Algorithms Registry . . . . . . . . . . . 38 + 6.1.1. Registration Template . . . . . . . . . . . . . . . . 39 + 6.1.2. Initial Contents . . . . . . . . . . . . . . . . . . 39 + 6.2. HTTP Signature Metadata Parameters Registry . . . . . . . 41 + 6.2.1. Registration Template . . . . . . . . . . . . . . . . 41 + 6.2.2. Initial Contents . . . . . . . . . . . . . . . . . . 41 + 6.3. HTTP Signature Specialty Component Identifiers + Registry . . . . . . . . . . . . . . . . . . . . . . . . 41 + 6.3.1. Registration Template . . . . . . . . . . . . . . . . 42 + 6.3.2. Initial Contents . . . . . . . . . . . . . . . . . . 42 + 7. Security Considerations . . . . . . . . . . . . . . . . . . . 43 + 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 44 + 8.1. Normative References . . . . . . . . . . . . . . . . . . 44 + 8.2. Informative References . . . . . . . . . . . . . . . . . 45 + Appendix A. Detecting HTTP Message Signatures . . . . . . . . . 46 + Appendix B. Examples . . . . . . . . . . . . . . . . . . . . . . 46 + B.1. Example Keys . . . . . . . . . . . . . . . . . . . . . . 46 + B.1.1. Example Key RSA test . . . . . . . . . . . . . . . . 46 + B.1.2. Example RSA PSS Key . . . . . . . . . . . . . . . . . 47 + B.1.3. Example ECC P-256 Test Key . . . . . . . . . . . . . 48 + B.1.4. Example Shared Secret . . . . . . . . . . . . . . . . 49 + B.2. Test Cases . . . . . . . . . . . . . . . . . . . . . . . 49 + B.2.1. Minimal Signature Using rsa-pss-sha512 . . . . . . . 50 + B.2.2. Selective Covered Components using rsa-pss-sha512 . . 50 + B.2.3. Full Coverage using rsa-pss-sha512 . . . . . . . . . 51 + B.2.4. Signing a Response using ecdsa-p256-sha256 . . . . . 52 + B.2.5. Signing a Request using hmac-sha256 . . . . . . . . . 53 + B.3. TLS-Terminating Proxies . . . . . . . . . . . . . . . . . 53 + Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 55 + Document History . . . . . . . . . . . . . . . . . . . . . . . . 56 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 59 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 @@ -143,61 +160,68 @@ 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 + and authenticity for components of 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 + authentication codes (MACs) over only the components of the message + that are 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: + The signing 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. + different protocol elements and other components of HTTP messages. * Algorithms for generating and verifying signatures over HTTP - message content using this nomenclature and rule set. + message components using this nomenclature and rule set. * A mechanism for attaching a signature and related metadata to an HTTP message. + This document also provides a mechanism for one party to signal to + another party that a signature is desired in one or more subsequent + messages. This optional negotiation mechanism can be used along with + opportunistic or application-driven message signatures by either + party. + 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. + and verifier to have the exact same signature input. Since the exact + raw bytes of the message cannot be relied upon as a reliable source + of signature input, the signer and verifier must derive the signature + input 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. + components are 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 @@ -224,46 +248,46 @@ * 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: + prevent signature verification, even when performed on message + components 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 + insensitive components 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. + Additionally, all changes to components 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- @@ -277,38 +301,68 @@ 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: + HTTP Message Signature: + A digital signature or keyed MAC that covers one or more portions + of an HTTP message. Note that a given HTTP Message can contain + multiple HTTP Message Signatures. + Signer: The entity that is generating or has generated an HTTP Message - Signature. + Signature. Note that multiple entities can act as signers and + apply separate HTTP Message Signatures to a given HTTP Message. 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 Message Component: + A portion of an HTTP message that is capable of being covered by + an HTTP Message Signature. - HTTP Signature Algorithm: + HTTP Message Component Identifier: + + A value that uniquely identifies a specific HTTP Message Component + in respect to a particular HTTP Message Signature and the HTTP + Message it applies to. + + HTTP Message Component Value: + The value associated with a given component identifier within the + context of a particular HTTP Message. Component values are + derived from the HTTP Message and are usually subject to a + canonicalization process. + + Covered Components: + An ordered set of HTTP message component identifiers for fields + (Section 2.1) and specialty components (Section 2.3) that + indicates the set of message components covered by the signature, + not including the "@signature-params" specialty identifier itself. + The order of this set is preserved and communicated between the + signer and verifier to facilitate reconstruction of the signature + input. + + Signature Input: + The sequence of bytes processed by the HTTP Message Signature + algorithm to produce the HTTP Message Signature. The signature + input is generated by the signer and verifier using the covered + components set and the HTTP Message. + + HTTP Message 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. @@ -334,522 +388,885 @@ value. 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 + * The set of component 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 + of the signature parameters (Section 2.3.1) 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. + signature is appropriate for the key material. For example, the + process could use the "alg" parameter of the signature parameters + (Section 2.3.1) 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. + An application using signatures also has to ensure that the verifier + will have access to all required information to re-create the + signature input string. For example, a server behind a reverse proxy + would need to know the original request URI to make use of + identifiers like "@target-uri". Additionally, an application using + signatures in responses would need to ensure that clients receiving + signed responses have access to all the signed portions, including + any portions of the request that were signed by the server. + 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 +2. HTTP Message Components - 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 + In order to allow signers and verifiers to establish which components + are covered by a signature, this document defines component + identifiers for components covered by an HTTP Message Signature, a + set of rules for deriving and canonicalizing the values associated + with these component identifiers from the HTTP Message, and the means for combining these canonicalized values into a signature input - string. + string. The values for these items MUST be accessible to both the + signer and the verifier of the message, which means these are usually + derived from aspects of the HTTP message or signature itself. - 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. + Some HTTP message components can undergo transformations that change + the bitwise value without altering meaning of the component's value + (for example, the merging together of header fields with the same + name). Message component values 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 component identifier that transform the identifier's + associated component value 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. + Component identifiers are serialized using the production grammar + defined by RFC8941, Section 4 [RFC8941]. The component identifier + itself is an "sf-string" value and MAY define parameters which are + included using the "parameters" rule. - content-identifier = sf-string parameters + component-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"". + Note that this means the value of the component 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. + The following sections define component identifier types, their + parameters, their associated values, and the canonicalization rules + for their values. The method for combining component identifiers + into the signature input is defined in Section 2.4. -2.1. HTTP Headers +2.1. HTTP Fields - 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. + The component identifier for an HTTP field is the lowercased form of + its field name. While HTTP field names are case-insensitive, + implementations MUST use lowercased field names (e.g., "content- + type", "date", "etag") when using them as component identifiers. - Unless overridden by additional parameters and rules, the HTTP header - field value MUST be canonicalized with the following steps: + Unless overridden by additional parameters and rules, the HTTP 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. + the 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. + The resulting string is the canonicalized component value. -2.1.1. Canonicalized Structured HTTP Headers +2.1.1. Canonicalized Structured HTTP Fields - 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 + If value of the the HTTP field in question is a structured field + ([RFC8941]), the component identifier MAY include the "sf" parameter. + If this parameter is included, the HTTP field 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. + [RFC8941]. For example, this process will replace any optional + internal whitespace with a single space character. - The resulting string is used as the field value input in Section 2.1. + The resulting string is used as the component value 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 + Host: 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 - + X-Dictionary: a=1, b=2;x=1;y=2, c=(a b c) 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 | + | "host" | www.example.com | +---------------------+----------------------------------+ | "x-empty-header" | | +---------------------+----------------------------------+ | "x-obs-fold-header" | Obsolete line folding. | +---------------------+----------------------------------+ | "x-ows-header" | Leading and trailing whitespace. | +---------------------+----------------------------------+ + | "x-dictionary" | a=1, b=2;x=1;y=2, c=(a b c) | + +---------------------+----------------------------------+ + | "x-dictionary";sf | a=1, b=2;x=1;y=2, c=(a b c) | + +---------------------+----------------------------------+ Table 1: Non-normative examples of header field canonicalization. 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 by using the parameter "key" on the component identifier + for the field. 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. + that item. 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: + header field, whose value is known 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: + component identifiers, given that field: - +======================+=====================+ - | Content Identifier | Canonicalized Value | - +======================+=====================+ + +======================+=================+ + | Component Identifier | Component 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. +2.3. Specialty Components - 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: + Message components not found in an HTTP field can be included in the + signature input by defining a component identifier and the + canonicalization method for its component value. - @request-target The target request endpoint. (Section 2.3.1) + To differentiate specialty component identifiers from HTTP fields, + specialty component identifiers MUST start with the "at" "@" + character. This specification defines the following specialty + component identifiers: @signature-params The signature metadata parameters for this - signature. (Section 2.3.2) + signature. (Section 2.3.1) - Additional specialty content identifiers MAY be defined and - registered in the HTTP Signatures Specialty Content Identifier - Registry. (Section 5.3) + @method The method used for a request. (Section 2.3.2) -2.3.1. Request Target + @target-uri The full target URI for a request. (Section 2.3.3) - 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. + @authority The authority of the target URI for a request. + (Section 2.3.4) - Its value is canonicalized as follows: + @scheme The scheme of the target URI for a request. (Section 2.3.5) - 1. Take the lowercased HTTP method of the message. + @request-target The request target. (Section 2.3.6) - 2. Append a space " ". + @path The absolute path portion of the target URI for a request. + (Section 2.3.7) - 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. + @query The query portion of the target URI for a request. + (Section 2.3.8) -2.3.1.1. Canonicalization Examples + @query-params The parsed query parameters of the target URI for a + request. (Section 2.3.9) - The following table contains non-normative example HTTP messages and - their canonicalized "@request-target" values. + @status The status code for a response. (Section 2.3.10). - +=========================+=================+ - |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| | - +-------------------------+-----------------+ + @request-response A signature from a request message that resulted + in this response message. (Section 2.3.11) - Table 3: Non-normative examples of "@request-target" - canonicalization. + Additional specialty component identifiers MAY be defined and + registered in the HTTP Signatures Specialty Component Identifier + Registry. (Section 6.3) -2.3.2. Signature Parameters +2.3.1. 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. + information regarding the signature's generation and verification, + such as the set of covered components, a timestamp, identifiers for + verification key material, and other utilities. - * "alg": The HTTP message signature algorithm from the HTTP Message - Signature Algorithm Registry, as an "sf-string" value. + The signature parameters component identifier is "@signature-params". - * "keyid": The identifier for the key material as an "sf-string" - value. + The signature parameters component value is the serialization of the + signature parameters for this signature, including the covered + components set with all associated parameters. These parameters + include any of the following: * "created": Creation time as an "sf-integer" UNIX timestamp value. - Sub-second precision is not supported. + Sub-second precision is not supported. Inclusion of this + parameter is RECOMMENDED. * "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. + * "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. + Additional parameters can be defined in the HTTP Signature Parameters - Registry (Section 5.2.2). + Registry (Section 6.2.2). - The signature parameters are serialized using the rules in Section 4 - of RFC8941 [RFC8941] as follows: + The signature parameters component value is serialized as a + parameterized inner list 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. + 2. Determine an order for the component identifiers of the covered + components. Once this order is chosen, it cannot be changed. + This order MUST be the same order as used in creating the + signature input (Section 2.4). - 3. Serialize the content identifiers of the covered content, + 3. Serialize the component identifiers of the covered components, 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. + parameters that are not available or not used for this message + signature. - 6. The output contains the signature parameters value. + 6. The output contains the signature parameters component 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. + component value instead of the "sf-list" serialization in order to + facilitate this value's inclusion in message fields such as the + "Signature-Input" field'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" \ + NOTE: '\' line wrapping per RFC 8792 + + ("@target-uri" "@authority" "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. + in the entry. + +2.3.2. Method + + The "@method" component identifier refers to the HTTP method of a + request message. The component value of is canonicalized by taking + the value of the method as a string. Note that the method name is + case-sensitive as per [SEMANTICS] Section 9.1, and conventionally + standardized method names are uppercase US-ASCII. If used, the + "@method" component identifier MUST occur only once in the covered + components. + + For example, the following request message: + + POST /path?param=value HTTP/1.1 + Host: www.example.com + + Would result in the following "@method" value: + + "@method": POST + + If used in a response message, the "@method" component identifier + refers to the associated component value of the request that + triggered the response message being signed. + +2.3.3. Target URI + + The "@target-uri" component identifier refers to the target URI of a + request message. The component value is the full absolute target URI + of the request, potentially assembled from all available parts + including the authority and request target as described in + [SEMANTICS] Section 7.1. If used, the "@target-uri" component + identifier MUST occur only once in the covered components. + + For example, the following message sent over HTTPS: + + POST /path?param=value HTTP/1.1 + Host: www.example.com + + Would result in the following "@target-uri" value: + + "@target-uri": https://www.example.com/path?param=value + + If used in a response message, the "@target-uri" component identifier + refers to the associated component value of the request that + triggered the response message being signed. + +2.3.4. Authority + + The "@authority" component identifier refers to the authority + component of the target URI of the HTTP request message, as defined + in [SEMANTICS] Section 7.2. In HTTP 1.1, this is usually conveyed + using the "Host" header, while in HTTP 2 and HTTP 3 it is conveyed + using the ":authority" pseudo-header. The value is the fully- + qualified authority component of the request, comprised of the host + and, optionally, port of the request target, as a string. The + component value MUST be normalized according to the rules in + [SEMANTICS] Section 4.2.3. Namely, the host name is normalized to + lowercase and the default port is omitted. If used, the "@authority" + component identifier MUST occur only once in the covered components. + + For example, the following request message: + + POST /path?param=value HTTP/1.1 + Host: www.example.com + + Would result in the following "@authority" component value: + + "@authority": www.example.com + + If used in a response message, the "@authority" component identifier + refers to the associated component value of the request that + triggered the response message being signed. + +2.3.5. Scheme + + The "@scheme" component identifier refers to the scheme of the target + URL of the HTTP request message. The component value is the scheme + as a string as defined in [SEMANTICS] Section 4.2. While the scheme + itself is case-insensitive, it MUST be normalized to lowercase for + inclusion in the signature input string. If used, the "@scheme" + component identifier MUST occur only once in the covered components. + + For example, the following request message requested over plain HTTP: + + POST /path?param=value HTTP/1.1 + Host: www.example.com + + Would result in the following "@scheme" value: + + "@scheme": http + + If used in a response message, the "@scheme" component identifier + refers to the associated component value of the request that + triggered the response message being signed. + +2.3.6. Request Target + + The "@request-target" component identifier refers to the full request + target of the HTTP request message, as defined in [SEMANTICS] + Section 7.1. The component value of the request target can take + different forms, depending on the type of request, as described + below. If used, the "@request-target" component identifier MUST + occur only once in the covered components. + + For HTTP 1.1, the component value is equivalent to the request target + portion of the request line. However, this value is more difficult + to reliably construct in other versions of HTTP. Therefore, it is + NOT RECOMMENDED that this identifier be used when versions of HTTP + other than 1.1 might be in use. + + The origin form value is combination of the absolute path and query + components of the request URL. For example, the following request + message: + + POST /path?param=value HTTP/1.1 + Host: www.example.com + + Would result in the following "@request-target" component value: + + "@request-target": /path?param=value + + The following request to an HTTP proxy with the absolute-form value, + containing the fully qualified target URI: + + GET https://www.example.com/path?param=value HTTP/1.1 + + Would result in the following "@request-target" component value: + + "@request-target": https://www.example.com/path?param=value + + The following CONNECT request with an authority-form value, + containing the host and port of the target: + + CONNECT www.example.com:80 HTTP/1.1 + Host: www.example.com + + Would result in the following "@request-target" component value: + + "@request-target": www.example.com:80 + + The following OPTIONS request message with the asterisk-form value, + containing a single asterisk "*" character: + + OPTIONS * HTTP/1.1 + Host: www.example.com + + Would result in the following "@request-target" component value: + + "@request-target": * + If used in a response message, the "@request-target" component + identifier refers to the associated component value of the request + that triggered the response message being signed. + +2.3.7. Path + + The "@path" component identifier refers to the target path of the + HTTP request message. The component value is the absolute path of + the request target defined by [RFC3986], with no query component and + no trailing "?" character. The value is normalized according to the + rules in [SEMANTICS] Section 4.2.3. Namely, an empty path string is + normalized as a single slash "/" character, and path components are + represented by their values after decoding any percent-encoded + octets. If used, the "@path" component identifier MUST occur only + once in the covered components. + + For example, the following request message: + + POST /path?param=value HTTP/1.1 + Host: www.example.com + + Would result in the following "@path" value: + + "@path": /path + + If used in a response message, the "@path" identifier refers to the + associated component value of the request that triggered the response + message being signed. + +2.3.8. Query + + The "@query" component identifier refers to the query component of + the HTTP request message. The component value is the entire + normalized query string defined by [RFC3986], including the leading + "?" character. The value is normalized according to the rules in + [SEMANTICS] Section 4.2.3. Namely, percent-encoded octets are + decoded. If used, the "@query" component identifier MUST occur only + once in the covered components. + + For example, the following request message: + + POST /path?param=value&foo=bar&baz=batman HTTP/1.1 + Host: www.example.com + + Would result in the following "@query" value: + + "@query": ?param=value&foo=bar&baz=batman + The following request message: + + POST /path?queryString HTTP/1.1 + Host: www.example.com + + Would result in the following "@query" value: + + "@query": ?queryString + + If used in a response message, the "@query" component identifier + refers to the associated component value of the request that + triggered the response message being signed. + +2.3.9. Query Parameters + + If a request target URI uses HTML form parameters in the query string + as defined in [HTMLURL] Section 5, the "@query-params" component + identifier allows addressing of individual query parameters. The + query parameters MUST be parsed according to [HTMLURL] Section 5.1, + resulting in a list of ("nameString", "valueString") tuples. The + REQUIRED "name" parameter of each input identifier contains the + "nameString" of a single query parameter. Several different named + query parameters MAY be included in the covered components. Single + named parameters MAY occur in any order in the covered components. + + The component value of a single named parameter is the the + "valueString" of the named query parameter defined by [HTMLURL] + Section 5.1, which is the value after percent-encoded octets are + decoded. Note that this value does not include any leading "?" + characters, equals sign "=", or separating "&" characters. Named + query parameters with an empty "valueString" are included with an + empty string as the component value. + + If a parameter name occurs multiple times in a request, all parameter + values of that name MUST be included in separate signature input + lines in the order in which the parameters occur in the target URI. + + For example for the following request: + + POST /path?param=value&foo=bar&baz=batman&qux= HTTP/1.1 + Host: www.example.com + + Indicating the "baz", "qux" and "param" named query parameters in + would result in the following "@query-param" value: + + "@query-params";name="baz": batman + "@query-params";name="qux": + "@query-params";name="param": value + If used in a response message, the "@query-params" component + identifier refers to the associated component value of the request + that triggered the response message being signed. + +2.3.10. Status Code + + The "@status" component identifier refers to the three-digit numeric + HTTP status code of a response message as defined in [SEMANTICS] + Section 15. The component value is the serialized three-digit + integer of the HTTP response code, with no descriptive text. If + used, the "@status" component identifier MUST occur only once in the + covered components. + + For example, the following response message: + + HTTP/1.1 200 OK + Date: Fri, 26 Mar 2010 00:05:00 GMT + + Would result in the following "@status" value: + + "@status": 200 + + The "@status" component identifier MUST NOT be used in a request + message. + +2.3.11. Request-Response Signature Binding + + When a signed request message results in a signed response message, + the "@request-response" component identifier can be used to + cryptographically link the request and the response to each other by + including the identified request signature value in the response's + signature input without copying the value of the request's signature + to the response directly. This component identifier has a single + REQUIRED parameter: + + "key" Identifies which signature from the response to sign. + + The component value is the "sf-binary" representation of the + signature value of the referenced request identified by the "key" + parameter. + + For example, when serving this signed request: + + NOTE: '\' line wrapping per RFC 8792 + + 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 + Content-Length: 18 + Signature-Input: sig1=("@authority" "content-type")\ + ;created=1618884475;keyid="test-key-rsa-pss" + Signature: sig1=:KuhJjsOKCiISnKHh2rln5ZNIrkRvue0DSu5rif3g7ckTbbX7C4\ + Jp3bcGmi8zZsFRURSQTcjbHdJtN8ZXlRptLOPGHkUa/3Qov79gBeqvHNUO4bhI27p\ + 4WzD1bJDG9+6ml3gkrs7rOvMtROObPuc78A95fa4+skS/t2T7OjkfsHAm/enxf1fA\ + wkk15xj0n6kmriwZfgUlOqyff0XLwuH4XFvZ+ZTyxYNoo2+EfFg4NVfqtSJch2WDY\ + 7n/qmhZOzMfyHlggWYFnDpyP27VrzQCQg8rM1Crp6MrwGLa94v6qP8pq0sQVq2DLt\ + 4NJSoRRqXTvqlWIRnexmcKXjQFVz6YSA==: + + {"hello": "world"} + + This would result in the following unsigned response message: + + HTTP/1.1 200 OK + Date: Tue, 20 Apr 2021 02:07:56 GMT + Content-Type: application/json + Content-Length: 62 + + {"busy": true, "message": "Your call is very important to us"} + + The server signs the response with its own key and includes the + signature of "sig1" from the request in the covered components of the + response. The signature input string for this example is: + + NOTE: '\' line wrapping per RFC 8792 + + "content-type": application/json + "content-length": 62 + "@status": 200 + "@request-response";key="sig1": :KuhJjsOKCiISnKHh2rln5ZNIrkRvue0DSu\ + 5rif3g7ckTbbX7C4Jp3bcGmi8zZsFRURSQTcjbHdJtN8ZXlRptLOPGHkUa/3Qov79\ + gBeqvHNUO4bhI27p4WzD1bJDG9+6ml3gkrs7rOvMtROObPuc78A95fa4+skS/t2T7\ + OjkfsHAm/enxf1fAwkk15xj0n6kmriwZfgUlOqyff0XLwuH4XFvZ+ZTyxYNoo2+Ef\ + Fg4NVfqtSJch2WDY7n/qmhZOzMfyHlggWYFnDpyP27VrzQCQg8rM1Crp6MrwGLa94\ + v6qP8pq0sQVq2DLt4NJSoRRqXTvqlWIRnexmcKXjQFVz6YSA==: + "@signature-params": ("content-type" "content-length" "@status" \ + "@request-response";key="sig1");created=1618884475\ + ;keyid="test-key-ecc-p256" + + The signed response message is: + + NOTE: '\' line wrapping per RFC 8792 + + HTTP/1.1 200 OK + Date: Tue, 20 Apr 2021 02:07:56 GMT + Content-Type: application/json + Content-Length: 62 + Signature-Input: sig1=("content-type" "content-length" "@status" \ + "@request-response";key="sig1");created=1618884475\ + ;keyid="test-key-ecc-p256" + Signature: sig1=:crVqK54rxvdx0j7qnt2RL1oQSf+o21S/6Uk2hyFpoIfOT0q+Hv\ + msYAXUXzo0Wn8NFWh/OjWQOXHAQdVnTk87Pw==: + + {"busy": true, "message": "Your call is very important to us"} + + Since the request's signature value itself is not repeated in the + response, the requester MUST keep the original signature value around + long enough to validate the signature of the response. + + The "@request-response" component identifier MUST NOT be used in a + request message. 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: + The signature input is a US-ASCII string containing the canonicalized + HTTP message components 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 components + (including their 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 + 2. For each message component item in the covered components set (in order): - 1. Append the identifier for the covered content serialized - according to the "content-identifier" rule. + 1. Append the component identifier for the covered component + serialized according to the "component-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) + 4. Append the covered component's canonicalized component value, + as defined by the HTTP message component 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: + 3. Append the signature parameters component (Section 2.3.1) as + follows: - 1. Append the identifier for the signature parameters serialized - according to the "content-identifier" rule, ""@signature- - params"" + 1. Append the component identifier for the signature parameters + serialized according to the "component-identifier" rule, i.e. + ""@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. Append the signature parameters' canonicalized component + value as defined in Section 2.3.1 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: + If covered components reference a component identifier that cannot be + resolved to a component 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 signer or verifier does not understand the component + identifier. - * The identifier identifies a header field that is not present in + * The component identifier identifies a 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 + * The component identifier is a Dictionary member identifier that + references a field that is not present in the message, is not a Dictionary 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 + * The component identifier is a Dictionary member identifier that + references a member that is not present in the 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 components consist of the "@method", "@path", and + "@authority" specialty component identifiers followed by the "Cache- + Control", "X-Empty-Header", "X-Example" HTTP headers, in order. The + signature parameters consist of a creation timestamp is "1618884475" + and the key identifier is "test-key-rsa-pss". The signature input + string for this message with these parameters is: - 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: + NOTE: '\' line wrapping per RFC 8792 - "@request-target": get /foo - "host": example.org - "date": Tue, 20 Apr 2021 02:07:55 GMT + "@method": GET + "@path": /foo + "@authority": example.org "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" + "@signature-params": ("@method" "@path" "@authority" \ + "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. + a subset of the components of an HTTP message in addition to metadata + about the signature itself. When successfully verified against an + HTTP message, an HTTP Message Signature provides cryptographic proof + that the message is semantically equivalent to the message for which + the signature was generated, with respect to the subset of message + components that was signed. 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. + 4. The signer creates an ordered set of component identifiers + representing the message components to be covered by the + signature, and attaches signature metadata parameters to this + set. The serialized value of this is later used as the value of + the "Signature-Input" field as described in Section 4.1. - * Once an order of covered content is chosen, the order MUST NOT - change for the life of the signature. + * Once an order of covered components 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. + * Each covered component identifier MUST be either an HTTP field + in the message Section 2.1 or a specialty component identifier + listed in Section 2.3 or its associated registry. - * Signers SHOULD include "@request-target" in the covered - content list. + * Signers of a request SHOULD include some or all of the message + control data in the covered components, such as the "@method", + "@authority", "@target-uri", or some combination thereof. - * 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. + * Signers SHOULD include the "created" signature metadata + parameter to indicate when the signature was created. - * 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. + * The "@signature-params" specialty component identifier is not + explicitly listed in the list of covered component + 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. - * 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. + * Further guidance on what to include in this set and in what + order is out of scope for this document. - 5. The signer creates the signature input string. (Section 2.4) + 5. The signer creates the signature input string based on these + signature parameters. (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. + field 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== + NOTE: '\' line wrapping per RFC 8792 + + P0wLUszWQjoi54udOtydf9IWTfNhy+r53jGFj9XZuP4uKwxyJo1RSHi+oEF1FuX6O29\ + d+lbxwwBao1BAgadijW+7O/PyezlTnqAOVPWx9GlyntiCiHzC87qmSQjvu1CFyFuWSj\ + dGa3qLYYlNm7pVaJFalQiKWnUaqfT4LyttaXyoyZW84jS8gyarxAiWI97mPXU+OVM64\ + +HVBHmnEsS+lTeIsEQo36T3NFf2CujWARPQg53r58RmpZ+J9eKR2CD6IJQvacn5A4Ix\ + 5BUAVGqlyp8JYm+S/CWJi31PNUjRRCusCVRj05NrxABNFv3r5S9IXf2fYJK+eyW4AiG\ + VMvMcOg== 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 + 1. Parse the "Signature" and "Signature-Input" fields 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. + which signature should be processed for this message. If an + applicable 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. + 2. Parse the values of the chosen "Signature-Input" 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. + 3. Parse the value of the corresponding "Signature" field to get the + byte array value of the signature to be verified. 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. + message components 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 @@ -873,58 +1290,61 @@ 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. + value of the "SignatureInput" field for this signature serialized + according to the rules described in Section 2.3.1, not including + the signature's label from the "Signature-Input" field. 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. + If any of the above steps fail or produce an error, 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). + "Authorization", "Digest"). * Enforcing a maximum signature age. + * Prohibition of signature metadata parameters, such as runtime + algorithm signaling with the "alg" parameter. + * Prohibiting the use of certain algorithms, or mandating the use of - an algorithm. + a specific algorithm. * Requiring keys to be of a certain size (e.g., 2048 bits vs. 1024 bits). - * Enforcing uniqueness of a nonce value. + * 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. @@ -932,35 +1352,36 @@ 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"): + ("Ks"), and outputs the signature output 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 + defined in Section 2.3.1, 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 @@ -1056,162 +1477,314 @@ 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. + "Signature-Input" and "Signature" HTTP fields, both defined within + this specification. When attached to a message, an HTTP message + signature is identified by a label. This label MUST be unique within + a given HTTP message and MUST be used in both the "Signature-Input" + and "Signature". The label is chosen by the signer, except where a + specific label is dictated by protocol negotiations. - 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. + An HTTP message signature MUST use both fields containing the same + labels: the "Signature" HTTP field contains the signature value, + while the "Signature-Input" HTTP field identifies the covered + components and parameters that describe how the signature was + generated. Each field contains labeled values and 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 +4.1. The 'Signature-Input' HTTP Field - 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 + The "Signature-Input" HTTP field is a Dictionary Structured Field + [RFC8941] containing the metadata for one or more message signatures + generated from components 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. + of the covered components including all signature metadata + parameters, using the serialization process defined in Section 2.3.1. - Signature-Input: sig1=("@request-target" "host" "date" \ + NOTE: '\' line wrapping per RFC 8792 + + Signature-Input: sig1=("@method" "@target-uri" "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 + To facilitate signature validation, the "Signature-Input" field 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 signer MAY include the "Signature-Input" field as a trailer to + facilitate signing a message after its content has been processed by + the signer. However, since intermediaries are allowed to drop + trailers as per [SEMANTICS], it is RECOMMENDED that the "Signature- + Input" HTTP field be included only as a header to avoid signatures + being inadvertently stripped from a message. - 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 + Multiple "Signature-Input" fields MAY be included in a single HTTP + message. The signature labels MUST be unique across all field + values. + +4.2. The 'Signature' HTTP Field + + The "Signature" HTTP field is a Dictionary Structured field [RFC8941] + containing one or more message signatures generated from components + 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 + Structured field 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" HTTP field that does not have a corresponding member in + the HTTP message's "Signature-Input" HTTP field MUST be ignored. - Signature: sig1=:lPxkxqDEPhgrx1yPaKLO7eJ+oPjSwsQ5NjWNRfYP7Jw0FwnK1k\ - 8/GH7g5s2q0VTTKVmxyfpUDp/HsDphh5Z7Fa/lvtujHyFe/0EP9z7bnVb7YBZrxV5\ - 2LGvP8p4APhOYuG4yaHz478GsJav9BQYK0B2IOHdLFJe8qwWPJs07J47gPewpNwCt\ - 0To/zZ2KPpylGX5UHVgJPUom64KjX43u2OwIvSoPEYk4nuBvLR9yxYAHURaTfLoED\ - UCtY1FsU1hOfG3jAlcT6illfnyS72PEdSSzw1KsxroMj9IYpFhva77YxmJRk4pCIW\ - 0F0Kj0ukl7J4y2aZJHMCYI3g8yfqh/wQ==: + NOTE: '\' line wrapping per RFC 8792 + + Signature: sig1=:P0wLUszWQjoi54udOtydf9IWTfNhy+r53jGFj9XZuP4uKwxyJo\ + 1RSHi+oEF1FuX6O29d+lbxwwBao1BAgadijW+7O/PyezlTnqAOVPWx9GlyntiCiHz\ + C87qmSQjvu1CFyFuWSjdGa3qLYYlNm7pVaJFalQiKWnUaqfT4LyttaXyoyZW84jS8\ + gyarxAiWI97mPXU+OVM64+HVBHmnEsS+lTeIsEQo36T3NFf2CujWARPQg53r58Rmp\ + Z+J9eKR2CD6IJQvacn5A4Ix5BUAVGqlyp8JYm+S/CWJi31PNUjRRCusCVRj05NrxA\ + BNFv3r5S9IXf2fYJK+eyW4AiGVMvMcOg==: + + The signer MAY include the "Signature" field as a trailer to + facilitate signing a message after its content has been processed by + the signer. However, since intermediaries are allowed to drop + trailers as per [SEMANTICS], it is RECOMMENDED that the "Signature- + Input" HTTP field be included only as a header to avoid signatures + being inadvertently stripped from a message. + + Multiple "Signature" fields MAY be included in a single HTTP message. + The signature labels MUST be unique across all field values. 4.3. Multiple Signatures + Multiple distinct signatures MAY be included in a single message. 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. + Dictionary Structured fields, they can be used to include multiple + signatures within the same HTTP message by using distinct signature + labels. For example, a signer may include multiple signatures + signing the same message components with different keys or algorithms + to support verifiers with different capabilities, or a reverse proxy + may include information about the client in fields when forwarding + the request to a service host, including a signature over the + client's original signature values. 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: + proxy sets in addition to the examples in the previous sections. - "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")\ + NOTE: '\' line wrapping per RFC 8792 + + Forwarded: for=192.0.2.123 + Signature-Input: sig1=("@method" "@path" "@authority" \ + "cache-control" "x-empty-header" "x-example")\ + ;created=1618884475;keyid="test-key-rsa-pss" + Signature: sig1=:P0wLUszWQjoi54udOtydf9IWTfNhy+r53jGFj9XZuP4uKwxyJo\ + 1RSHi+oEF1FuX6O29d+lbxwwBao1BAgadijW+7O/PyezlTnqAOVPWx9GlyntiCi\ + HzC87qmSQjvu1CFyFuWSjdGa3qLYYlNm7pVaJFalQiKWnUaqfT4LyttaXyoyZW8\ + 4jS8gyarxAiWI97mPXU+OVM64+HVBHmnEsS+lTeIsEQo36T3NFf2CujWARPQg53\ + r58RmpZ+J9eKR2CD6IJQvacn5A4Ix5BUAVGqlyp8JYm+S/CWJi31PNUjRRCusCV\ + Rj05NrxABNFv3r5S9IXf2fYJK+eyW4AiGVMvMcOg==: + + The client's request includes a signature value under the label + "sig1", which the proxy signs in addition to the "Forwarded" header + defined in [RFC7239]. Note that since the client's signature already + covers the client's "Signature-Input" value for "sig1", this value is + transitively covered by the proxy's signature and need not be added + explicitly. This results in a signature input string of: + + NOTE: '\' line wrapping per RFC 8792 + + "signature";key="sig1": :P0wLUszWQjoi54udOtydf9IWTfNhy+r53jGFj9XZuP\ + 4uKwxyJo1RSHi+oEF1FuX6O29d+lbxwwBao1BAgadijW+7O/PyezlTnqAOVPWx9Gl\ + yntiCiHzC87qmSQjvu1CFyFuWSjdGa3qLYYlNm7pVaJFalQiKWnUaqfT4LyttaXyo\ + yZW84jS8gyarxAiWI97mPXU+OVM64+HVBHmnEsS+lTeIsEQo36T3NFf2CujWARPQg\ + 53r58RmpZ+J9eKR2CD6IJQvacn5A4Ix5BUAVGqlyp8JYm+S/CWJi31PNUjRRCusCV\ + Rj05NrxABNFv3r5S9IXf2fYJK+eyW4AiGVMvMcOg==: + "forwarded": for=192.0.2.123 + "@signature-params": ("signature";key="sig1" "forwarded")\ ;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== + NOTE: '\' line wrapping per RFC 8792 + + cjGvZwbsq9JwexP9TIvdLiivxqLINwp/ybAc19KOSQuLvtmMt3EnZxNiE+797dXK2cj\ + PPUFqoZxO8WWx1SnKhAU9SiXBr99NTXRmA1qGBjqus/1Yxwr8keB8xzFt4inv3J3zP0\ + k6TlLkRJstkVnNjuhRIUA/ZQCo8jDYAl4zWJJjppy6Gd1XSg03iUa0sju1yj6rcKbMA\ + BBuzhUz4G0u1hZkIGbQprCnk/FOsqZHpwaWvY8P3hmcDHkNaavcokmq+3EBDCQTzgwL\ + qfDmV0vLCXtDda6CNO2Zyum/pMGboCnQn/VkQ+j8kSydKoFg6EbVuGbrQijth6I0dDX\ + 2/HYcJg== 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. + original signature is included under the identifier "sig1", and the + reverse proxy's signature is included under the label "proxy_sig". + The proxy uses the key "test-key-rsa" to create its signature using + the "rsa-v1_5-sha256" signature algorithm, while the client's + original signature was made using the key id of "test-key-rsa-pss" + and an RSA PSS signature algorithm. - X-Forwarded-For: 192.0.2.123 - Signature-Input: sig1=("@request-target" "host" "date" \ + NOTE: '\' line wrapping per RFC 8792 + + Forwarded: for=192.0.2.123 + Signature-Input: sig1=("@method" "@path" "@authority" \ "cache-control" "x-empty-header" "x-example")\ ;created=1618884475;keyid="test-key-rsa-pss", \ - proxy_sig=("signature";key="sig1" "x-forwarded-for")\ + proxy_sig=("signature";key="sig1" "forwarded")\ ;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==: + Signature: sig1=:P0wLUszWQjoi54udOtydf9IWTfNhy+r53jGFj9XZuP4uKwxyJo\ + 1RSHi+oEF1FuX6O29d+lbxwwBao1BAgadijW+7O/PyezlTnqAOVPWx9GlyntiCi\ + HzC87qmSQjvu1CFyFuWSjdGa3qLYYlNm7pVaJFalQiKWnUaqfT4LyttaXyoyZW8\ + 4jS8gyarxAiWI97mPXU+OVM64+HVBHmnEsS+lTeIsEQo36T3NFf2CujWARPQg53\ + r58RmpZ+J9eKR2CD6IJQvacn5A4Ix5BUAVGqlyp8JYm+S/CWJi31PNUjRRCusCV\ + Rj05NrxABNFv3r5S9IXf2fYJK+eyW4AiGVMvMcOg==:, \ + proxy_sig=:cjGvZwbsq9JwexP9TIvdLiivxqLINwp/ybAc19KOSQuLvtmMt3EnZx\ + NiE+797dXK2cjPPUFqoZxO8WWx1SnKhAU9SiXBr99NTXRmA1qGBjqus/1Yxwr8k\ + eB8xzFt4inv3J3zP0k6TlLkRJstkVnNjuhRIUA/ZQCo8jDYAl4zWJJjppy6Gd1X\ + Sg03iUa0sju1yj6rcKbMABBuzhUz4G0u1hZkIGbQprCnk/FOsqZHpwaWvY8P3hm\ + cDHkNaavcokmq+3EBDCQTzgwLqfDmV0vLCXtDda6CNO2Zyum/pMGboCnQn/VkQ+\ + j8kSydKoFg6EbVuGbrQijth6I0dDX2/HYcJg==: 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. + verified independently for the same message, based on the needs of + the application. Since the proxy's signature covers the client + signature, the backend service fronted by the proxy can trust that + the proxy has validated the incoming signature. -5. IANA Considerations +5. Requesting Signatures -5.1. HTTP Signature Algorithms Registry + While a signer is free to attach a signature to a request or response + without prompting, it is often desirable for a potential verifier to + signal that it expects a signature from a potential signer using the + "Accept-Signature" field. + + The message to which the requested signature is applied is known as + the "target message". When the "Accept-Signature" field is sent in + an HTTP Request message, the field indicates that the client desires + the server to sign the response using the identified parameters and + the target message is the response to this request. All responses + from resources that support such signature negotiation SHOULD either + be uncacheable or contain a "Vary" header field that lists "Accept- + Signature", in order to prevent a cache from returning a response + with a signature intended for a different request. + + When the "Accept-Signature" field is used in an HTTP Response + message, the field indicates that the server desires the client to + sign its next request to the server with the identified parameters, + and the target message is the client's next request. The client can + choose to also continue signing future requests to the same server in + the same way. + + The target message of an "Accept-Signature" field MUST include all + labeled signatures indicated in the "Accept-Header" signature, each + covering the same identified components of the "Accept-Signature" + field. + + The sender of an "Accept-Signature" field MUST include identifiers + that are appropriate for the type of the target message. For + example, if the target message is a response, the identifiers can not + include the "@status" identifier. + +5.1. The Accept-Signature Field + + The "Accept-Signature" HTTP header field is a Dictionary Structured + field [RFC8941] containing the metadata for one or more requested + message signatures to be generated from message components of the + target HTTP message. Each member describes a single message + signature. The member's name is an identifier that uniquely + identifies the requested message signature within the context of the + target HTTP message. The member's value is the serialization of the + desired covered components of the target message, including any + allowed signature metadata parameters, using the serialization + process defined in Section 2.3.1. + + NOTE: '\' line wrapping per RFC 8792 + + Accept-Signature: sig1=("@method" "@target-uri" "host" "date" \ + "cache-control" "x-empty-header" "x-example")\ + ;keyid="test-key-rsa-pss" + + The requested signature MAY include parameters, such as a desired + algorithm or key identifier. These parameters MUST NOT include + parameters that the signer is expected to generate, including the + "created" and "nonce" parameters. + +5.2. Processing an Accept-Signature + + The receiver of an "Accept-Signature" field fulfills that header as + follows: + + 1. Parse the field value as a Dictionary + 2. For each member of the dictionary: + + 1. The name of the member is the label of the output signature + as specified in Section 4.1 + + 2. Parse the value of the member to obtain the set of covered + component identifiers + + 3. Process the requested parameters, such as the signing + algorithm and key material. If any requested parameters + cannot be fulfilled, or if the requested parameters conflict + with those deemed appropriate to the target message, the + process fails and returns an error. + + 4. Select any additional parameters necessary for completing the + signature + + 5. Create the "Signature-Input" and "Signature" header values + and associate them with the label + + 3. Optionally create any additional "Signature-Input" and + "Signature" values, with unique labels not found in the "Accept- + Signature" field + + 4. Combine all labeled "Signature-Input" and "Signature" values and + attach both headers to the target message + + Note that by this process, a signature applied to a target message + MUST have the same label, MUST have the same set of covered + component, and MAY have additional parameters. Also note that the + target message MAY include additional signatures not specified by the + "Accept-Signature" field. + +6. IANA Considerations + +6.1. 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 + Section 6.1.2. 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. + Section 6.1.1. 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 +6.1.1. Registration Template Algorithm Name: - 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 @@ -1220,215 +1793,259 @@ 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 +6.1.2. Initial Contents -5.1.2.1. rsa-pss-sha512 +6.1.2.1. 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 +6.1.2.2. rsa-v1_5-sha256 Algorithm Name: "rsa-v1_5-sha256" Status: Active Description: RSASSA-PKCS1-v1_5 using SHA-256 Specification document(s): [[This document]], Section 3.3.2 -5.1.2.3. hmac-sha256 +6.1.2.3. 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 +6.1.2.4. 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 +6.2. HTTP Signature Metadata Parameters Registry - This document defines the "Signature-Input" Structured Header, whose - member values may have parameters containing metadata about a message + This document defines the signature parameters structure, the values + of which 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. + signature parameters structure. Initial values for this registry are + given in Section 6.2.2. 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 6.2.1. -5.2.1. Registration Template -5.2.2. Initial Contents +6.2.1. Registration Template + +6.2.2. 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 | + | alg | Active | Section 2.3.1 of this document | +---------+--------+--------------------------------+ - | created | Active | Section 2.3.2 of this document | + | created | Active | Section 2.3.1 of this document | +---------+--------+--------------------------------+ - | expires | Active | Section 2.3.2 of this document | + | expires | Active | Section 2.3.1 of this document | +---------+--------+--------------------------------+ - | keyid | Active | Section 2.3.2 of this document | + | keyid | Active | Section 2.3.1 of this document | +---------+--------+--------------------------------+ - | nonce | Active | Section 2.3.2 of this document | + | nonce | Active | Section 2.3.1 of this document | +---------+--------+--------------------------------+ - Table 4: Initial contents of the HTTP Signature + Table 3: Initial contents of the HTTP Signature Metadata Parameters Registry. -5.3. HTTP Signature Specialty Content Identifiers Registry +6.3. HTTP Signature Specialty Component 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. + components, including components that can be generated from the + context of the HTTP message outside of the HTTP fields. These + components are identified by a unique string, known as the component + identifier. IANA is asked to create and maintain a new registry + typed "HTTP Signature Specialty Component Identifiers" to record and + maintain the set of non-field component identifiers and the methods + to produce their associated component values. Initial values for + this registry are given in Section 6.3.2. 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 6.3.1. -5.3.1. Registration Template +6.3.1. Registration Template -5.3.2. Initial Contents +6.3.2. Initial Contents The table below contains the initial contents of the HTTP Signature - Specialty Content Identifiers Registry. + Specialty Component Identifiers Registry. - +===================+========+================================+ - | Name | Status | Reference(s) | - +===================+========+================================+ - | @request-target | Active | Section 2.3.1 of this document | - +-------------------+--------+--------------------------------+ - | @signature-params | Active | Section 2.3.2 of this document | - +-------------------+--------+--------------------------------+ + +===================+========+===================+==================+ + | Name | Status | Target | Reference | + +===================+========+===================+==================+ + | @signature-params | Active | Request, | Section 2.3.1 of | + | | | Response | this document | + +-------------------+--------+-------------------+------------------+ + | @method | Active | Request, | Section 2.3.2 of | + | | | Related-Response | this document | + +-------------------+--------+-------------------+------------------+ + | @authority | Active | Request, | Section 2.3.4 of | + | | | Related-Response | this document | + +-------------------+--------+-------------------+------------------+ + | @scheme | Active | Request, | Section 2.3.5 of | + | | | Related-Response | this document | + +-------------------+--------+-------------------+------------------+ + | @target-uri | Active | Request, | Section 2.3.3 of | + | | | Related-Response | this document | + +-------------------+--------+-------------------+------------------+ + | @request-target | Active | Request, | Section 2.3.6 of | + | | | Related-Response | this document | + +-------------------+--------+-------------------+------------------+ + | @path | Active | Request, | Section 2.3.7 of | + | | | Related-Response | this document | + +-------------------+--------+-------------------+------------------+ + | @query | Active | Request, | Section 2.3.8 of | + | | | Related-Response | this document | + +-------------------+--------+-------------------+------------------+ + | @query-params | Active | Request, | Section 2.3.9 of | + | | | Related-Response | this document | + +-------------------+--------+-------------------+------------------+ + | @status | Active | Response | Section 2.3.10 | + | | | | of this document | + +-------------------+--------+-------------------+------------------+ + | @request-response | Active | Section 2.3.11 | | + | | | of this document | | + +-------------------+--------+-------------------+------------------+ - Table 5: Initial contents of the HTTP Signature Specialty - Content Identifiers Registry. + Table 4: Initial contents of the HTTP Signature Specialty Component + Identifiers Registry. -6. Security Considerations +7. 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. )) - + components need 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 +8. References -7.1. Normative References +8.1. Normative References [FIPS186-4] "Digital Signature Standard (DSS)", 2013, . - [HTTP2] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext - Transfer Protocol Version 2 (HTTP/2)", RFC 7540, - DOI 10.17487/RFC7540, May 2015, - . + [HTMLURL] "URL (Living Standard)", 2021, + . [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, - . + Fielding, R. T., Nottingham, M., and J. Reschke, + "HTTP/1.1", Work in Progress, Internet-Draft, draft-ietf- + httpbis-messaging-17, 25 July 2021, + . [POSIX.1] "The Open Group Base Specifications Issue 7, 2018 edition", 2018, . [RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed- Hashing for Message Authentication", RFC 2104, DOI 10.17487/RFC2104, February 1997, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . + [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform + Resource Identifier (URI): Generic Syntax", STD 66, + RFC 3986, DOI 10.17487/RFC3986, January 2005, + . + [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [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, . [RFC8941] Nottingham, M. and P-H. Kamp, "Structured Field Values for HTTP", RFC 8941, DOI 10.17487/RFC8941, February 2021, . [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, - . + Fielding, R. T., Nottingham, M., and J. Reschke, "HTTP + Semantics", Work in Progress, Internet-Draft, draft-ietf- + httpbis-semantics-17, 25 July 2021, + . -7.2. Informative References +8.2. Informative References + + [I-D.ietf-httpbis-client-cert-field] + Campbell, B. and M. Bishop, "Client-Cert HTTP Header + Field: Conveying Client Certificate Information from TLS + Terminating Reverse Proxies to Origin Server + Applications", Work in Progress, Internet-Draft, draft- + ietf-httpbis-client-cert-field-00, 8 June 2021, + . [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, . [RFC7239] Petersson, A. and M. Nilsson, "Forwarded HTTP Extension", RFC 7239, DOI 10.17487/RFC7239, June 2014, . @@ -1456,30 +2073,30 @@ [WP-HTTP-Sig-Audit] "Security Considerations for HTTP Signatures", 2013, . 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 + field 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 + "Signature-Input" field 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 + Input" field is present, all "Signature" fields 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. @@ -1589,20 +2206,22 @@ -----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". + NOTE: '\' line wrapping per RFC 8792 + 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: @@ -1619,145 +2238,282 @@ 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"} -B.2.1. Minimal Signature Header using rsa-pss-sha512 +B.2.1. Minimal Signature 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 + "test-request", covering none of the components of the HTTP message request but providing a timestamped signature proof of possession of the key. The corresponding signature input is: + NOTE: '\' line wrapping per RFC 8792 + "@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: + NOTE: '\' line wrapping per RFC 8792 + 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==: + Signature: sig1=:HWP69ZNiom9Obu1KIdqPPcu/C1a5ZUMBbqS/xwJECV8bhIQVmE\ + AAAzz8LQPvtP1iFSxxluDO1KE9b8L+O64LEOvhwYdDctV5+E39Jy1eJiD7nYREBgx\ + TpdUfzTO+Trath0vZdTylFlxK4H3l3s/cuFhnOCxmFYgEa+cw+StBRgY1JtafSFwN\ + cZgLxVwialuH5VnqJS4JN8PHD91XLfkjMscTo4jmVMpFd3iLVe0hqVFl7MDt6TMkw\ + IyVFnEZ7B/VIQofdShO+C/7MuupCSLVjQz5xA+Zs6Hw+W9ESD/6BuGs6LF1TcKLxW\ + +5K+2zvDY/Cia34HNpRW5io7Iv9/b7iQ==: -B.2.2. Header Coverage using rsa-pss-sha512 + Note that since the covered components list is empty, this signature + could be applied by an attacker to an unrelated HTTP message. + Therefore, use of an empty covered components set is discouraged. - This example covers all the specified headers in "test-request" - except for the body digest header using the "rsa-pss-sha512" - algorithm. +B.2.2. Selective Covered Components using rsa-pss-sha512 + + This example covers additional components in "test-request" using the + "rsa-pss-sha512" algorithm. The corresponding signature input is: - "host": example.com - "date": Tue, 20 Apr 2021 02:07:55 GMT + NOTE: '\' line wrapping per RFC 8792 + + "@authority": example.com "content-type": application/json - "@signature-params": ("host" "date" "content-type")\ + "@signature-params": ("@authority" "content-type")\ ;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=("host" "date" "content-type")\ + NOTE: '\' line wrapping per RFC 8792 + + Signature-Input: sig1=("@authority" "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==: + Signature: sig1=:ik+OtGmM/kFqENDf9Plm8AmPtqtC7C9a+zYSaxr58b/E6h81gh\ + JS3PcH+m1asiMp8yvccnO/RfaexnqanVB3C72WRNZN7skPTJmUVmoIeqZncdP2mlf\ + xlLP6UbkrgYsk91NS6nwkKC6RRgLhBFqzP42oq8D2336OiQPDAo/04SxZt4Wx9nDG\ + uy2SfZJUhsJqZyEWRk4204x7YEB3VxDAAlVgGt8ewilWbIKKTOKp3ymUeQIwptqYw\ + v0l8mN404PPzRBTpB7+HpClyK4CNp+SVv46+6sHMfJU4taz10s/NoYRmYCGXyadzY\ + YDj0BYnFdERB6NblI/AOWFGl5Axhhmjg==: 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. + This example covers all headers in "test-request" (including the + message body "Digest") plus various elements of the control data, + 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 + NOTE: '\' line wrapping per RFC 8792 + + "date": Tue, 20 Apr 2021 02:07:56 GMT + "@method": POST + "@path": /foo + "@query": ?param=value&pet=dog + "@authority": example.com "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" + "@signature-params": ("date" "@method" "@path" "@query" \ + "@authority" "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==: + NOTE: '\' line wrapping per RFC 8792 + + Signature-Input: sig1=("date" "@method" "@path" "@query" \ + "@authority" "content-type" "digest" "content-length")\ + ;created=1618884475;keyid="test-key-rsa-pss" + Signature: sig1=:JuJnJMFGD4HMysAGsfOY6N5ZTZUknsQUdClNG51VezDgPUOW03\ + QMe74vbIdndKwW1BBrHOHR3NzKGYZJ7X3ur23FMCdANe4VmKb3Rc1Q/5YxOO8p7Ko\ + yfVa4uUcMk5jB9KAn1M1MbgBnqwZkRWsbv8ocCqrnD85Kavr73lx51k1/gU8w673W\ + T/oBtxPtAn1eFjUyIKyA+XD7kYph82I+ahvm0pSgDPagu917SlqUjeaQaNnlZzO03\ + Iy1RZ5XpgbNeDLCqSLuZFVID80EohC2CQ1cL5svjslrlCNstd2JCLmhjL7xV3NYXe\ + rLim4bqUQGRgDwNJRnqobpS6C1NBns/Q==: + + Note in this example that the value of the "Date" header and the + value of the "created" signature parameter need not be the same. + This is due to the fact that the "Date" header is added when creating + the HTTP Message and the "created" parameter is populated when + creating the signature over that message, and these two times could + vary. If the "Date" header is covered by the signature, it is up to + the verifier to determine whether its value has to match that of the + "created" parameter or not. 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: - "date": Tue, 20 Apr 2021 02:07:56 GMT + NOTE: '\' line wrapping per RFC 8792 + "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" + "@signature-params": ("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==: + NOTE: '\' line wrapping per RFC 8792 + + Signature-Input: sig1=("content-type" "digest" "content-length")\ + ;created=1618884475;keyid="test-key-ecc-p256" + Signature: sig1=:n8RKXkj0iseWDmC6PNSQ1GX2R9650v+lhbb6rTGoSrSSx18zmn\ + 6fPOtBx48/WffYLO0n1RHHf9scvNGAgGq52Q==: 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 + NOTE: '\' line wrapping per RFC 8792 + + "@authority": example.com "date": Tue, 20 Apr 2021 02:07:55 GMT "content-type": application/json - "@signature-params": ("host" "date" "content-type")\ + "@signature-params": ("@authority" "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")\ + NOTE: '\' line wrapping per RFC 8792 + + Signature-Input: sig1=("@authority" "date" "content-type")\ ;created=1618884475;keyid="test-shared-secret" - Signature: sig1=:x54VEvVOb0TMw8fUbsWdUHqqqOre+K7sB/LqHQvnfaQ=: + Signature: sig1=:fN3AMNGbx0V/cIEKkZOvLOoC3InI+lM2+gTv22x3ia8=: + +B.3. TLS-Terminating Proxies + + In this example, there is a TLS-terminating reverse proxy sitting in + front of the resource. The client does not sign the request but + instead uses mutual TLS to make its call. The terminating proxy + validates the TLS stream and injects a "Client-Cert" header according + to [I-D.ietf-httpbis-client-cert-field]. By signing this header + field, a reverse proxy can not only attest to its own validation of + the initial request but also authenticate itself to the backend + system independently of the client's actions. The client makes the + following request to the TLS terminating proxy using mutual TLS: + + 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 + Content-Length: 18 + + {"hello": "world"} + + The proxy processes the TLS connection and extracts the client's TLS + certificate to a "Client-Cert" header field and passes it along to + the internal service hosted at "service.internal.example". This + results in the following unsigned request: + + NOTE: '\' line wrapping per RFC 8792 + + POST /foo?Param=value&pet=Dog HTTP/1.1 + Host: service.internal.example + Date: Tue, 20 Apr 2021 02:07:55 GMT + Content-Type: application/json + Content-Length: 18 + Client-Cert: :MIIBqDCCAU6gAwIBAgIBBzAKBggqhkjOPQQDAjA6MRswGQYDVQQKD\ + BJMZXQncyBBdXRoZW50aWNhdGUxGzAZBgNVBAMMEkxBIEludGVybWVkaWF0ZSBDQT\ + AeFw0yMDAxMTQyMjU1MzNaFw0yMTAxMjMyMjU1MzNaMA0xCzAJBgNVBAMMAkJDMFk\ + wEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE8YnXXfaUgmnMtOXU/IncWalRhebrXmck\ + C8vdgJ1p5Be5F/3YC8OthxM4+k1M6aEAEFcGzkJiNy6J84y7uzo9M6NyMHAwCQYDV\ + R0TBAIwADAfBgNVHSMEGDAWgBRm3WjLa38lbEYCuiCPct0ZaSED2DAOBgNVHQ8BAf\ + 8EBAMCBsAwEwYDVR0lBAwwCgYIKwYBBQUHAwIwHQYDVR0RAQH/BBMwEYEPYmRjQGV\ + 4YW1wbGUuY29tMAoGCCqGSM49BAMCA0gAMEUCIBHda/r1vaL6G3VliL4/Di6YK0Q6\ + bMjeSkC3dFCOOB8TAiEAx/kHSB4urmiZ0NX5r5XarmPk0wmuydBVoU4hBVZ1yhk=: + + {"hello": "world"} + + Without a signature, the internal service would need to trust that + the incoming connection has the right information. By signing the + "Client-Cert" header and other portions of the internal request, the + internal service can be assured that the correct party, the trusted + proxy, has processed the request and presented it to the correct + service. The proxy's signature input consists of the following: + + NOTE: '\' line wrapping per RFC 8792 + + "@path": /foo + "@query": Param=value&pet=Dog + "@method": POST + "@authority": service.internal.example + "client-cert": :MIIBqDCCAU6gAwIBAgIBBzAKBggqhkjOPQQDAjA6MRswGQYDVQQ\ + KDBJMZXQncyBBdXRoZW50aWNhdGUxGzAZBgNVBAMMEkxBIEludGVybWVkaWF0ZSBD\ + QTAeFw0yMDAxMTQyMjU1MzNaFw0yMTAxMjMyMjU1MzNaMA0xCzAJBgNVBAMMAkJDM\ + FkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE8YnXXfaUgmnMtOXU/IncWalRhebrXm\ + ckC8vdgJ1p5Be5F/3YC8OthxM4+k1M6aEAEFcGzkJiNy6J84y7uzo9M6NyMHAwCQY\ + DVR0TBAIwADAfBgNVHSMEGDAWgBRm3WjLa38lbEYCuiCPct0ZaSED2DAOBgNVHQ8B\ + Af8EBAMCBsAwEwYDVR0lBAwwCgYIKwYBBQUHAwIwHQYDVR0RAQH/BBMwEYEPYmRjQ\ + GV4YW1wbGUuY29tMAoGCCqGSM49BAMCA0gAMEUCIBHda/r1vaL6G3VliL4/Di6YK0\ + Q6bMjeSkC3dFCOOB8TAiEAx/kHSB4urmiZ0NX5r5XarmPk0wmuydBVoU4hBVZ1yhk=: + "@signature-params": ("@path" "@query" "@method" "@authority" \ + "client-cert");created=1618884475;keyid="test-key-ecc-p256" + + This results in the following signature: + + NOTE: '\' line wrapping per RFC 8792 + + 5gudRjXaHrAYbEaQUOoY9TuvqWOdPcspkp7YyKCB0XhyAG9cB715hucPPanEK0OVyiN\ + LJqcoq2Yn1DPWQcnbog== + + Which results in the following signed request sent from the proxy to + the internal service: + + NOTE: '\' line wrapping per RFC 8792 + + POST /foo?Param=value&pet=Dog HTTP/1.1 + Host: service.internal.example + Date: Tue, 20 Apr 2021 02:07:55 GMT + Content-Type: application/json + Content-Length: 18 + Client-Cert: :MIIBqDCCAU6gAwIBAgIBBzAKBggqhkjOPQQDAjA6MRswGQYDVQQKD\ + BJMZXQncyBBdXRoZW50aWNhdGUxGzAZBgNVBAMMEkxBIEludGVybWVkaWF0ZSBDQT\ + AeFw0yMDAxMTQyMjU1MzNaFw0yMTAxMjMyMjU1MzNaMA0xCzAJBgNVBAMMAkJDMFk\ + wEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE8YnXXfaUgmnMtOXU/IncWalRhebrXmck\ + C8vdgJ1p5Be5F/3YC8OthxM4+k1M6aEAEFcGzkJiNy6J84y7uzo9M6NyMHAwCQYDV\ + R0TBAIwADAfBgNVHSMEGDAWgBRm3WjLa38lbEYCuiCPct0ZaSED2DAOBgNVHQ8BAf\ + 8EBAMCBsAwEwYDVR0lBAwwCgYIKwYBBQUHAwIwHQYDVR0RAQH/BBMwEYEPYmRjQGV\ + 4YW1wbGUuY29tMAoGCCqGSM49BAMCA0gAMEUCIBHda/r1vaL6G3VliL4/Di6YK0Q6\ + bMjeSkC3dFCOOB8TAiEAx/kHSB4urmiZ0NX5r5XarmPk0wmuydBVoU4hBVZ1yhk=: + Signature-Input: ttrp=("@path" "@query" "@method" "@authority" \ + "client-cert");created=1618884475;keyid="test-key-ecc-p256" + Signature: ttrp=:5gudRjXaHrAYbEaQUOoY9TuvqWOdPcspkp7YyKCB0XhyAG9cB7\ + 15hucPPanEK0OVyiNLJqcoq2Yn1DPWQcnbog==: + + {"hello": "world"} + + The internal service can validate the proxy's signature and therefore + be able to trust that the client's certificate has been appropriately + processed. 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 @@ -1770,20 +2526,36 @@ 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 + - -06 + + o Updated language for message components, including + identifiers and values. + + o Clarified that Signature-Input and Signature are fields + which can be used as headers or trailers. + + o Add "Accept-Signature" field and semantics for signature + negotiation. + + o Define new specialty content identifiers, re-defined + request-target identifier. + + o Added request-response binding. + - -05 o Remove list prefixes. o Clarify signature algorithm parameters. o Update and fix examples. o Add examples for ECC and HMAC.