< draft-jones-json-web-signature-02.txt   draft-jones-json-web-signature-03.txt >
Network Working Group M. Jones Network Working Group M. Jones
Internet-Draft Microsoft Internet-Draft Microsoft
Intended status: Standards Track D. Balfanz Intended status: Standards Track D. Balfanz
Expires: October 31, 2011 Google Expires: May 2, 2012 Google
J. Bradley J. Bradley
independent independent
Y. Goland Y. Goland
Microsoft Microsoft
J. Panzer J. Panzer
Google Google
N. Sakimura N. Sakimura
Nomura Research Institute Nomura Research Institute
P. Tarjan P. Tarjan
Facebook Facebook
April 29, 2011 October 30, 2011
JSON Web Signature (JWS) JSON Web Signature (JWS)
draft-jones-json-web-signature-02 draft-jones-json-web-signature-03
Abstract Abstract
JSON Web Signature (JWS) is a means of representing signed content JSON Web Signature (JWS) is a means of representing signed content
using JSON data structures. Related encryption capabilities are using JSON data structures. Related encryption capabilities are
described in the separate JSON Web Encryption (JWE) specification. described in the separate JSON Web Encryption (JWE) specification.
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
skipping to change at page 1, line 49 skipping to change at page 1, line 49
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on October 31, 2011. This Internet-Draft will expire on May 2, 2012.
Copyright Notice Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 3, line 13 skipping to change at page 3, line 13
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. JSON Web Signature (JWS) Overview . . . . . . . . . . . . . . 5 3. JSON Web Signature (JWS) Overview . . . . . . . . . . . . . . 5
3.1. Example JWS . . . . . . . . . . . . . . . . . . . . . . . 5 3.1. Example JWS . . . . . . . . . . . . . . . . . . . . . . . 5
4. JWS Header . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4. JWS Header . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Reserved Header Parameter Names . . . . . . . . . . . . . 6 4.1. Reserved Header Parameter Names . . . . . . . . . . . . . 6
4.2. Public Header Parameter Names . . . . . . . . . . . . . . 9 4.2. Public Header Parameter Names . . . . . . . . . . . . . . 10
4.3. Private Header Parameter Names . . . . . . . . . . . . . . 9 4.3. Private Header Parameter Names . . . . . . . . . . . . . . 10
5. Rules for Creating and Validating a JWS . . . . . . . . . . . 9 5. Rules for Creating and Validating a JWS . . . . . . . . . . . 10
6. Base64url encoding as used by JWSs . . . . . . . . . . . . . . 11 6. Signing JWSs with Cryptographic Algorithms . . . . . . . . . . 12
7. Signing JWSs with Cryptographic Algorithms . . . . . . . . . . 11 6.1. Creating a JWS with HMAC SHA-256, HMAC SHA-384, or
7.1. Creating a JWS with HMAC SHA-256, HMAC SHA-384, or HMAC SHA-512 . . . . . . . . . . . . . . . . . . . . . . . 13
HMAC SHA-512 . . . . . . . . . . . . . . . . . . . . . . . 12 6.2. Creating a JWS with RSA SHA-256, RSA SHA-384, or RSA
7.2. Creating a JWS with RSA SHA-256, RSA SHA-384, or RSA SHA-512 . . . . . . . . . . . . . . . . . . . . . . . . . 14
SHA-512 . . . . . . . . . . . . . . . . . . . . . . . . . 13 6.3. Creating a JWS with ECDSA P-256 SHA-256, ECDSA P-384
7.3. Creating a JWS with ECDSA P-256 SHA-256, ECDSA P-384 SHA-384, or ECDSA P-521 SHA-512 . . . . . . . . . . . . . 15
SHA-384, or ECDSA P-521 SHA-512 . . . . . . . . . . . . . 14 6.4. Additional Algorithms . . . . . . . . . . . . . . . . . . 17
7.4. Additional Algorithms . . . . . . . . . . . . . . . . . . 16 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 8. Security Considerations . . . . . . . . . . . . . . . . . . . 18
9. Security Considerations . . . . . . . . . . . . . . . . . . . 16 8.1. Unicode Comparison Security Issues . . . . . . . . . . . . 18
9.1. Unicode Comparison Security Issues . . . . . . . . . . . . 17 9. Open Issues and Things To Be Done (TBD) . . . . . . . . . . . 19
10. Open Issues and Things To Be Done (TBD) . . . . . . . . . . . 17 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 20
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18 10.1. Normative References . . . . . . . . . . . . . . . . . . . 20
11.1. Normative References . . . . . . . . . . . . . . . . . . . 18 10.2. Informative References . . . . . . . . . . . . . . . . . . 22
11.2. Informative References . . . . . . . . . . . . . . . . . . 20 Appendix A. JWS Examples . . . . . . . . . . . . . . . . . . . . 22
Appendix A. JWS Examples . . . . . . . . . . . . . . . . . . . . 20 A.1. JWS using HMAC SHA-256 . . . . . . . . . . . . . . . . . . 22
A.1. JWS using HMAC SHA-256 . . . . . . . . . . . . . . . . . . 20 A.1.1. Encoding . . . . . . . . . . . . . . . . . . . . . . . 22
A.1.1. Encoding . . . . . . . . . . . . . . . . . . . . . . . 21 A.1.2. Decoding . . . . . . . . . . . . . . . . . . . . . . . 24
A.1.2. Decoding . . . . . . . . . . . . . . . . . . . . . . . 22 A.1.3. Validating . . . . . . . . . . . . . . . . . . . . . . 24
A.1.3. Validating . . . . . . . . . . . . . . . . . . . . . . 22 A.2. JWS using RSA SHA-256 . . . . . . . . . . . . . . . . . . 24
A.2. JWS using RSA SHA-256 . . . . . . . . . . . . . . . . . . 23 A.2.1. Encoding . . . . . . . . . . . . . . . . . . . . . . . 25
A.2.1. Encoding . . . . . . . . . . . . . . . . . . . . . . . 23 A.2.2. Decoding . . . . . . . . . . . . . . . . . . . . . . . 28
A.2.2. Decoding . . . . . . . . . . . . . . . . . . . . . . . 26 A.2.3. Validating . . . . . . . . . . . . . . . . . . . . . . 28
A.2.3. Validating . . . . . . . . . . . . . . . . . . . . . . 26 A.3. JWS using ECDSA P-256 SHA-256 . . . . . . . . . . . . . . 29
A.3. JWS using ECDSA P-256 SHA-256 . . . . . . . . . . . . . . 27 A.3.1. Encoding . . . . . . . . . . . . . . . . . . . . . . . 29
A.3.1. Encoding . . . . . . . . . . . . . . . . . . . . . . . 27 A.3.2. Decoding . . . . . . . . . . . . . . . . . . . . . . . 30
A.3.2. Decoding . . . . . . . . . . . . . . . . . . . . . . . 28 A.3.3. Validating . . . . . . . . . . . . . . . . . . . . . . 31
A.3.3. Validating . . . . . . . . . . . . . . . . . . . . . . 29 Appendix B. Algorithm Identifier Cross-Reference . . . . . . . . 31
Appendix B. Algorithm Identifier Cross-Reference . . . . . . . . 29
Appendix C. Notes on implementing base64url encoding without Appendix C. Notes on implementing base64url encoding without
padding . . . . . . . . . . . . . . . . . . . . . . . 31 padding . . . . . . . . . . . . . . . . . . . . . . . 33
Appendix D. Acknowledgements . . . . . . . . . . . . . . . . . . 32 Appendix D. Acknowledgements . . . . . . . . . . . . . . . . . . 34
Appendix E. Document History . . . . . . . . . . . . . . . . . . 33 Appendix E. Document History . . . . . . . . . . . . . . . . . . 35
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 33 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 36
1. Introduction 1. Introduction
JSON Web Signature (JWS) is a compact signature format intended for JSON Web Signature (JWS) is a compact signature format intended for
space constrained environments such as HTTP Authorization headers and space constrained environments such as HTTP Authorization headers and
URI query parameters. It represents signed content using JSON URI query parameters. It represents signed content using JSON
[RFC4627] data structures. The JWS signature mechanisms are [RFC4627] data structures. The JWS signature mechanisms are
independent of the type of content being signed, allowing arbitrary independent of the type of content being signed, allowing arbitrary
content to be signed. A related encryption capability is described content to be signed. A related encryption capability is described
in a separate JSON Web Encryption (JWE) [JWE] specification. in a separate JSON Web Encryption (JWE) [JWE] specification.
2. Terminology 2. Terminology
JSON Web Signature (JWS) A data structure cryptographically securing JSON Web Signature (JWS) A data structure cryptographically securing
a JWS Header Input and a JWS Payload Input with a JWS Crypto a JWS Header and a JWS Payload with a JWS Signature.
Output.
JWS Header Input A string containing a base64url encoded JSON object JWS Header A string containing a JSON object that describes the
that describes the cryptographic operations applied to the JWS signature applied to the JWS Header and the JWS Payload to create
Header Input and the JWS Payload Input. the JWS Signature.
JWS Payload Input A string containing base64url encoded content. JWS Payload The bytes to be signed - a.k.a., the message.
JWS Crypto Output A string containing base64url encoded JWS Signature A byte array containing the cryptographic material
cryptographic material that secures the contents of the JWS Header that secures the contents of the JWS Header and the JWS Payload.
Input and the JWS Payload Input.
Decoded JWS Header Input JWS Header Input that has been base64url Encoded JWS Header Base64url encoding of the bytes of the UTF-8 RFC
decoded back into a JSON object. 3629 [RFC3629] representation of the JWS Header.
Decoded JWS Payload Input JWS Payload Input that has been base64url Encoded JWS Payload Base64url encoding of the JWS Payload.
decoded.
Decoded JWS Crypto Output JWS Crypto Output that has been base64url Encoded JWS Signature Base64url encoding of the JWS Signature.
decoded back into cryptographic material.
JWS Signing Input The concatenation of the JWS Header Input, a JWS Signing Input The concatenation of the Encoded JWS Header, a
period ('.') character, and the JWS Payload Input. period ('.') character, and the Encoded JWS Payload.
Header Parameter Names The names of the members within the JSON Header Parameter Names The names of the members within the JSON
object represented in a JWS Header Input. object represented in a JWS Header.
Header Parameter Values The values of the members within the JSON Header Parameter Values The values of the members within the JSON
object represented in a JWS Header Input. object represented in a JWS Header.
Digital Signature For the purposes of this specification, we use Digital Signature For the purposes of this specification, we use
this term to encompass both Hash-based Message Authentication this term to encompass both Hash-based Message Authentication
Codes (HMACs), which can provide authenticity but not non- Codes (HMACs), which can provide authenticity but not non-
repudiation, and digital signatures using public key algorithms, repudiation, and digital signatures using public key algorithms,
which can provide both. Readers should be aware of this which can provide both. Readers should be aware of this
distinction, despite the decision to use a single term for both distinction, despite the decision to use a single term for both
concepts to improve readability of the specification. concepts to improve readability of the specification.
Base64url Encoding For the purposes of this specification, this term Base64url Encoding For the purposes of this specification, this term
always refers to the he URL- and filename-safe Base64 encoding always refers to the he URL- and filename-safe Base64 encoding
described in RFC 4648 [RFC4648], Section 5, with the '=' padding described in RFC 4648 [RFC4648], Section 5, with the (non URL-
characters omitted, as permitted by Section 3.2. safe) '=' padding characters omitted, as permitted by Section 3.2.
(See Appendix C for notes on implementing base64url encoding
without padding.)
3. JSON Web Signature (JWS) Overview 3. JSON Web Signature (JWS) Overview
JWSs represent content that is base64url encoded and digitally JWS represents signed content using JSON data structures and
signed, and optionally encrypted, using JSON data structures. A base64url encoding. The representation consists of three parts: the
portion of the base64url encoded content that is signed is the JWS JWS Header, the JWS Payload, and the JWS Signature. The three parts
Payload Input. An accompanying base64url encoded JSON object - the are base64url-encoded for transmission, and typically represented as
JWS Header Input - describes the signature method used. the concatenation of the encoded strings in that order, with the
three strings being separated by period ('.') characters, as is done
when used in JSON Web Tokens (JWTs) [JWT].
The member names within the Decoded JWS Header Input are referred to A base64url encoded JSON object - the JWS Header - describes the
as Header Parameter Names. These names MUST be unique. The signature method used. A portion of the base64url encoded content
corresponding values are referred to as Header Parameter Values. that is signed is the Encoded JWS Payload. Finally, JWSs contain a
signature that ensures the integrity of the contents of the JWS
Header and the JWS Payload. This signature value is base64url
encoded to produce the Encoded JWS Signature.
JWSs contain a signature that ensures the integrity of the contents The member names within the JWS Header are referred to as Header
of the JWS Header Input and the JWS Payload Input. This signature Parameter Names. These names MUST be unique. The corresponding
value is the JWS Crypto Output. The JSON Header object MUST contain values are referred to as Header Parameter Values. The JWS Header
an "alg" parameter, the value of which is a string that unambiguously MUST contain an "alg" parameter, the value of which is a string that
identifies the algorithm used to sign the JWS Header Input and the unambiguously identifies the algorithm used to sign the JWS Header
JWS Payload Input to produce the JWS Crypto Output. and the JWS Payload to produce the JWS Signature.
3.1. Example JWS 3.1. Example JWS
The following example JSON header object declares that the encoded The following example JWS Header declares that the encoded object is
object is a JSON Web Token (JWT) [JWT] and the JWS Header Input and a JSON Web Token (JWT) [JWT] and the JWS Header and the JWS Payload
the JWS Payload Input are signed using the HMAC SHA-256 algorithm: are signed using the HMAC SHA-256 algorithm:
{"typ":"JWT", {"typ":"JWT",
"alg":"HS256"} "alg":"HS256"}
Base64url encoding the UTF-8 representation of the JSON header object Base64url encoding the bytes of the UTF-8 representation of the JWS
yields this JWS Header Input value: Header yields this Encoded JWS Header value:
eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9 eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9
The following is an example of a JSON object that can be encoded to The following is an example of a JSON object that can be used as a
produce a JWS Payload Input. (Note that the payload can be any JWS Payload. (Note that the payload can be any content, and need not
base64url encoded content, and need not be a base64url encoded JSON be a representation of a JSON object.)
object.)
{"iss":"joe", {"iss":"joe",
"exp":1300819380, "exp":1300819380,
"http://example.com/is_root":true} "http://example.com/is_root":true}
Base64url encoding the UTF-8 representation of the JSON object yields Base64url encoding the bytes of the UTF-8 representation of the JSON
the following JWS Payload Input. object yields the following Encoded JWS Payload.
eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ
Signing the UTF-8 representation of the JWS Signing Input (the Signing the UTF-8 representation of the JWS Signing Input (the
concatenation of the JWS Header Input, a period ('.') character, and concatenation of the Encoded JWS Header, a period ('.') character,
the JWS Payload Input) with the HMAC SHA-256 algorithm and base64url and the Encoded JWS Payload) with the HMAC SHA-256 algorithm and
encoding the result, as per Section 7.1, yields this JWS Crypto base64url encoding the result, as per Section 6.1, yields this
Output value: Encoded JWS Signature value:
dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk
This computation is illustrated in more detail in Appendix A.1. This computation is illustrated in more detail in Appendix A.1.
4. JWS Header 4. JWS Header
The members of the JSON object represented by the Decoded JWS Header The members of the JSON object represented by the JWS Header describe
Input describe the signature applied to the JWS Header Input and the the signature applied to the Encoded JWS Header and the Encoded JWS
JWS Payload Input and optionally additional properties of the JWS. Payload and optionally additional properties of the JWS.
Implementations MUST understand the entire contents of the header; Implementations MUST understand the entire contents of the header;
otherwise, the JWS MUST be rejected for processing. otherwise, the JWS MUST be rejected for processing.
4.1. Reserved Header Parameter Names 4.1. Reserved Header Parameter Names
The following header parameter names are reserved. All the names are The following header parameter names are reserved. All the names are
short because a core goal of JWSs is for the representations to be short because a core goal of JWSs is for the representations to be
compact. compact.
+-----------+--------+--------------+-------------------------------+ +-----------+--------+-------------+--------------------------------+
| Header | JSON | Header | Header Parameter Semantics | | Header | JSON | Header | Header Parameter Semantics |
| Parameter | Value | Parameter | | | Parameter | Value | Parameter | |
| Name | Type | Syntax | | | Name | Type | Syntax | |
+-----------+--------+--------------+-------------------------------+ +-----------+--------+-------------+--------------------------------+
| alg | string | StringAndURI | The "alg" (algorithm) header | | alg | string | StringOrURI | The "alg" (algorithm) header |
| | | | parameter identifies the | | | | | parameter identifies the |
| | | | cryptographic algorithm used | | | | | cryptographic algorithm used |
| | | | to secure the JWS. A list of | | | | | to secure the JWS. A list of |
| | | | reserved alg values is in | | | | | reserved alg values is in |
| | | | Table 3. The processing of | | | | | Table 3. The processing of |
| | | | the "alg" (algorithm) header | | | | | the "alg" (algorithm) header |
| | | | parameter, if present, | | | | | parameter, if present, |
| | | | requires that the value of | | | | | requires that the value of the |
| | | | the "alg" header parameter | | | | | "alg" header parameter MUST be |
| | | | MUST be one that is both | | | | | one that is both supported and |
| | | | supported and for which there | | | | | for which there exists a key |
| | | | exists a key for use with | | | | | for use with that algorithm |
| | | | that algorithm associated | | | | | associated with the signer of |
| | | | with the signer of the | | | | | the content. The "alg" |
| | | | content. The "alg" parameter | | | | | parameter value is case |
| | | | value is case sensitive. | | | | | sensitive. This header |
| | | | This header parameter is | | | | | parameter is REQUIRED. |
| | | | REQUIRED. | | typ | string | String | The "typ" (type) header |
| typ | string | String | The "typ" (type) header | | | | | parameter is used to declare |
| | | | parameter is used to declare | | | | | the type of the signed |
| | | | the type of the signed | | | | | content. The "typ" value is |
| | | | content. The "typ" value is | | | | | case sensitive. This header |
| | | | case sensitive. This header | | | | | parameter is OPTIONAL. |
| | | | parameter is OPTIONAL. | | jku | string | URL | The "jku" (JSON Web Key URL) |
| jku | string | URL | The "jku" (JSON Key URL) | | | | | header parameter is an |
| | | | header parameter is a URL | | | | | absolute URL that refers to a |
| | | | that points to JSON-encoded | | | | | resource for a set of |
| | | | public keys that can be used | | | | | JSON-encoded public keys, one |
| | | | to validate the signature. | | | | | of which corresponds to the |
| | | | The keys MUST be encoded as | | | | | key that was used to sign the |
| | | | per the JSON Web Key (JWK) | | | | | JWS. The keys MUST be encoded |
| | | | [JWK] specification. This | | | | | as described in the JSON Web |
| | | | header parameter is OPTIONAL. | | | | | Key (JWK) [JWK] specification. |
| kid | string | String | The "kid" (key ID) header | | | | | The protocol used to acquire |
| | | | parameter is a hint | | | | | the resource MUST provide |
| | | | indicating which specific key | | | | | integrity protection. An HTTP |
| | | | owned by the signer should be | | | | | GET request to retrieve the |
| | | | used to validate the | | | | | certificate MUST use TLS RFC |
| | | | signature. This allows | | | | | 2818 [RFC2818] RFC 5246 |
| | | | signers to explicitly signal | | | | | [RFC5246] with server |
| | | | a change of key to | | | | | authentication RFC 6125 |
| | | | recipients. Omitting this | | | | | [RFC6125]. This header |
| | | | parameter is equivalent to | | | | | parameter is OPTIONAL. |
| | | | setting it to an empty | | kid | string | String | The "kid" (key ID) header |
| | | | string. The interpretation | | | | | parameter is a hint indicating |
| | | | of the contents of the "kid" | | | | | which specific key owned by |
| | | | parameter is unspecified. | | | | | the signer should be used to |
| | | | This header parameter is | | | | | validate the signature. This |
| | | | OPTIONAL. | | | | | allows signers to explicitly |
| x5u | string | URL | The "x5u" (X.509 URL) header | | | | | signal a change of key to |
| | | | parameter is a URL utilizing | | | | | recipients. The |
| | | | TLS RFC 5785 [RFC5785] that | | | | | interpretation of the contents |
| | | | points to an X.509 public key | | | | | of the "kid" parameter is |
| | | | certificate or certificate | | | | | unspecified. This header |
| | | | chain that can be used to | | | | | parameter is OPTIONAL. |
| | | | validate the signature. This | | x5u | string | URL | The "x5u" (X.509 URL) header |
| | | | certificate or certificate | | | | | parameter is an absolute URL |
| | | | chain MUST use the PEM | | | | | that refers to a resource for |
| | | | encoding RFC 1421 [RFC1421] | | | | | the X.509 public key |
| | | | and MUST conform to RFC 5280 | | | | | certificate or certificate |
| | | | [RFC5280]. This header | | | | | chain corresponding to the key |
| | | | parameter is OPTIONAL. | | | | | used to sign the JWS. The |
| x5t | string | String | The "x5t" (x.509 certificate | | | | | identified resource MUST |
| | | | thumbprint) header parameter | | | | | provide a representation of |
| | | | provides a base64url encoded | | | | | the certificate or certificate |
| | | | SHA-1 thumbprint (a.k.a. | | | | | chain that conforms to RFC |
| | | | digest) of the DER encoding | | | | | 5280 [RFC5280] in PEM encoded |
| | | | of an X.509 certificate that | | | | | form RFC 1421 [RFC1421]. The |
| | | | can be used to match the | | | | | protocol used to acquire the |
| | | | certificate. This header | | | | | resource MUST provide |
| | | | parameter is OPTIONAL. | | | | | integrity protection. An HTTP |
+-----------+--------+--------------+-------------------------------+ | | | | GET request to retrieve the |
| | | | certificate MUST use TLS RFC |
| | | | 2818 [RFC2818] RFC 5246 |
| | | | [RFC5246] with server |
| | | | authentication RFC 6125 |
| | | | [RFC6125]. This header |
| | | | parameter is OPTIONAL. |
| x5t | string | String | The "x5t" (x.509 certificate |
| | | | thumbprint) header parameter |
| | | | provides a base64url encoded |
| | | | SHA-1 thumbprint (a.k.a. |
| | | | digest) of the DER encoding of |
| | | | an X.509 certificate that can |
| | | | be used to match the |
| | | | certificate. This header |
| | | | parameter is OPTIONAL. |
+-----------+--------+-------------+--------------------------------+
Table 1: Reserved Header Parameter Definitions Table 1: Reserved Header Parameter Definitions
Additional reserved header parameter names MAY be defined via the Additional reserved header parameter names MAY be defined via the
IANA JSON Web Signature Header Parameters registry, as per Section 8. IANA JSON Web Signature Header Parameters registry, as per Section 7.
The syntax values used above are defined as follows: The syntax values used above are defined as follows:
+--------------+----------------------------------------------------+ +-------------+-----------------------------------------------------+
| Syntax Name | Syntax Definition | | Syntax Name | Syntax Definition |
+--------------+----------------------------------------------------+ +-------------+-----------------------------------------------------+
| IntDate | The number of seconds from 1970-01-01T0:0:0Z as | | IntDate | The number of seconds from 1970-01-01T0:0:0Z as |
| | measured in UTC until the desired date/time. See | | | measured in UTC until the desired date/time. See |
| | RFC 3339 [RFC3339] for details regarding | | | RFC 3339 [RFC3339] for details regarding date/times |
| | date/times in general and UTC in particular. | | | in general and UTC in particular. |
| String | Any string value MAY be used. | | String | Any string value MAY be used. |
| StringAndURI | Any string value MAY be used but a value | | StringOrURI | Any string value MAY be used but a value containing |
| | containing a ":" character MUST be a URI as | | | a ":" character MUST be a URI as defined in RFC |
| | defined in RFC 3986 [RFC3986]. | | | 3986 [RFC3986]. |
| URL | A URL as defined in RFC 1738 [RFC1738]. | | URL | A URL as defined in RFC 1738 [RFC1738]. |
+--------------+----------------------------------------------------+ +-------------+-----------------------------------------------------+
Table 2: Header Parameter Syntax Definitions Table 2: Header Parameter Syntax Definitions
4.2. Public Header Parameter Names 4.2. Public Header Parameter Names
Additional header parameter names can be defined by those using JWSs. Additional header parameter names can be defined by those using JWSs.
However, in order to prevent collisions, any new header parameter However, in order to prevent collisions, any new header parameter
name or algorithm value SHOULD either be defined in the IANA JSON Web name or algorithm value SHOULD either be defined in the IANA JSON Web
Signature Header Parameters registry or be defined as a URI that Signature Header Parameters registry or be defined as a URI that
contains a collision resistant namespace. In each case, the definer contains a collision resistant namespace. In each case, the definer
skipping to change at page 9, line 49 skipping to change at page 10, line 49
Section 4.2. Unlike Public Names, these private names are subject to Section 4.2. Unlike Public Names, these private names are subject to
collision and should be used with caution. collision and should be used with caution.
New header parameters should be introduced sparingly, as they can New header parameters should be introduced sparingly, as they can
result in non-interoperable JWSs. result in non-interoperable JWSs.
5. Rules for Creating and Validating a JWS 5. Rules for Creating and Validating a JWS
To create a JWS, one MUST follow these steps: To create a JWS, one MUST follow these steps:
1. Create the payload content to be encoded as the Decoded JWS 1. Create the content to be used as the JWS Payload.
Payload Input.
2. Base64url encode the Decoded JWS Payload Input. This encoding 2. Base64url encode the JWS Payload. This encoding becomes the
becomes the JWS Payload Input. Encoded JWS Payload.
3. Create a JSON object containing a set of desired header 3. Create a JSON object containing a set of desired header
parameters. Note that white space is explicitly allowed in the parameters. Note that white space is explicitly allowed in the
representation and no canonicalization is performed before representation and no canonicalization is performed before
encoding. encoding.
4. Translate this JSON object's Unicode code points into UTF-8, as 4. Translate this JSON object's Unicode code points into UTF-8, as
defined in RFC 3629 [RFC3629]. defined in RFC 3629 [RFC3629].
5. Base64url encode the UTF-8 representation of this JSON object as 5. Base64url encode the UTF-8 representation of this JSON object as
defined in this specification (without padding). This encoding defined in this specification (without padding). This encoding
becomes the JWS Header Input. becomes the Encoded JWS Header.
6. Compute the JWS Crypto Output in the manner defined for the 6. Compute the JWS Signature in the manner defined for the
particular algorithm being used. The JWS Signing Input is always particular algorithm being used. The JWS Signing Input is always
the concatenation of the JWS Header Input, a period ('.') the concatenation of the Encoded JWS Header, a period ('.')
character, and the JWS Payload Input. The "alg" header parameter character, and the Encoded JWS Payload. The "alg" header
MUST be present in the JSON Header Input, with the algorithm parameter MUST be present in the JSON Header, with the algorithm
value accurately representing the algorithm used to construct the value accurately representing the algorithm used to construct the
JWS Crypto Input. JWS Signature.
7. Base64url encode the representation of the JWS Signature to
create the Encoded JWS Signature.
When validating a JWS, the following steps MUST be taken. If any of When validating a JWS, the following steps MUST be taken. If any of
the listed steps fails, then the signed content MUST be rejected. the listed steps fails, then the signed content MUST be rejected.
1. The JWS Payload Input MUST be successfully base64url decoded 1. The Encoded JWS Payload MUST be successfully base64url decoded
following the restriction given in this specification that no following the restriction given in this specification that no
padding characters have been used. padding characters have been used.
2. The JWS Header Input MUST be successfully base64url decoded 2. The Encoded JWS Header MUST be successfully base64url decoded
following the restriction given in this specification that no following the restriction given in this specification that no
padding characters have been used. padding characters have been used.
3. The Decoded JWS Header Input MUST be completely valid JSON syntax 3. The JWS Header MUST be completely valid JSON syntax conforming to
conforming to RFC 4627 [RFC4627]. RFC 4627 [RFC4627].
4. The JWS Crypto Output MUST be successfully base64url decoded 4. The Encoded JWS Signature MUST be successfully base64url decoded
following the restriction given in this specification that no following the restriction given in this specification that no
padding characters have been used. padding characters have been used.
5. The JWS Header Input MUST be validated to only include parameters 5. The JWS Header MUST be validated to only include parameters and
and values whose syntax and semantics are both understood and values whose syntax and semantics are both understood and
supported. supported.
6. The JWS Crypto Output MUST be successfully validated against the 6. The JWS Signature MUST be successfully validated against the JWS
JWS Header Input and JWS Payload Input in the manner defined for Header and JWS Payload in the manner defined for the algorithm
the algorithm being used, which MUST be accurately represented by being used, which MUST be accurately represented by the value of
the value of the "alg" header parameter, which MUST be present. the "alg" header parameter, which MUST be present.
Processing a JWS inevitably requires comparing known strings to Processing a JWS inevitably requires comparing known strings to
values in the header. For example, in checking what the algorithm values in the header. For example, in checking what the algorithm
is, the Unicode string encoding "alg" will be checked against the is, the Unicode string encoding "alg" will be checked against the
member names in the Decoded JWS Header Input to see if there is a member names in the JWS Header to see if there is a matching header
matching header parameter name. A similar process occurs when parameter name. A similar process occurs when determining if the
determining if the value of the "alg" header parameter represents a value of the "alg" header parameter represents a supported algorithm.
supported algorithm. Comparing Unicode strings, however, has Comparing Unicode strings, however, has significant security
significant security implications, as per Section 9. implications, as per Section 8.
Comparisons between JSON strings and other Unicode strings MUST be Comparisons between JSON strings and other Unicode strings MUST be
performed as specified below: performed as specified below:
1. Remove any JSON applied escaping to produce an array of Unicode 1. Remove any JSON applied escaping to produce an array of Unicode
code points. code points.
2. Unicode Normalization [USA15] MUST NOT be applied at any point to 2. Unicode Normalization [USA15] MUST NOT be applied at any point to
either the JSON string or to the string it is to be compared either the JSON string or to the string it is to be compared
against. against.
3. Comparisons between the two strings MUST be performed as a 3. Comparisons between the two strings MUST be performed as a
Unicode code point to code point equality comparison. Unicode code point to code point equality comparison.
6. Base64url encoding as used by JWSs 6. Signing JWSs with Cryptographic Algorithms
JWSs make use of the base64url encoding as defined in RFC 4648
[RFC4648]. As allowed by Section 3.2 of the RFC, this specification
mandates that base64url encoding when used with JWSs MUST NOT use
padding. The reason for this restriction is that the padding
character ('=') is not URL safe.
For notes on implementing base64url encoding without padding, see
Appendix C.
7. Signing JWSs with Cryptographic Algorithms
JWSs use specific cryptographic algorithms to sign the contents of JWSs use specific cryptographic algorithms to sign the contents of
the JWS Header Input and the JWS Payload Input. The use of the the JWS Header and the JWS Payload. The use of the following
following algorithms for producing JWSs is defined in this section. algorithms for producing JWSs is defined in this section. The table
The table below is the list of "alg" header parameter values reserved below is the list of "alg" header parameter values reserved by this
by this specification, each of which is explained in more detail in specification, each of which is explained in more detail in the
the following sections: following sections:
+--------------------+----------------------------------------------+ +--------------------+----------------------------------------------+
| Alg Parameter | Algorithm | | Alg Parameter | Algorithm |
| Value | | | Value | |
+--------------------+----------------------------------------------+ +--------------------+----------------------------------------------+
| HS256 | HMAC using SHA-256 hash algorithm | | HS256 | HMAC using SHA-256 hash algorithm |
| HS384 | HMAC using SHA-384 hash algorithm | | HS384 | HMAC using SHA-384 hash algorithm |
| HS512 | HMAC using SHA-512 hash algorithm | | HS512 | HMAC using SHA-512 hash algorithm |
| RS256 | RSA using SHA-256 hash algorithm | | RS256 | RSA using SHA-256 hash algorithm |
| RS384 | RSA using SHA-384 hash algorithm | | RS384 | RSA using SHA-384 hash algorithm |
skipping to change at page 12, line 32 skipping to change at page 13, line 32
Table 3: JSON Web Signature Reserved Algorithm Values Table 3: JSON Web Signature Reserved Algorithm Values
See Appendix B for a table cross-referencing the "alg" values used in See Appendix B for a table cross-referencing the "alg" values used in
this specification with the equivalent identifiers used by other this specification with the equivalent identifiers used by other
standards and software packages. standards and software packages.
Of these algorithms, only HMAC SHA-256 MUST be implemented by Of these algorithms, only HMAC SHA-256 MUST be implemented by
conforming implementations. It is RECOMMENDED that implementations conforming implementations. It is RECOMMENDED that implementations
also support the RSA SHA-256 and ECDSA P-256 SHA-256 algorithms. also support the RSA SHA-256 and ECDSA P-256 SHA-256 algorithms.
Support for other algorithms is OPTIONAL. Support for other algorithms and key sizes is OPTIONAL.
The signed content for a JWS is the same for all algorithms: the The signed content for a JWS is the same for all algorithms: the
concatenation of the JWS Header Input, a period ('.') character, and concatenation of the Encoded JWS Header, a period ('.') character,
the JWS Payload Input. This character sequence is referred to as the and the Encoded JWS Payload. This character sequence is referred to
JWS Signing Input. Note that if the JWS represents a JWT, this as the JWS Signing Input. Note that if the JWS represents a JWT,
corresponds to the portion of the JWT representation preceding the this corresponds to the portion of the JWT representation preceding
second period character. The UTF-8 representation of the JWS Signing the second period character. The UTF-8 representation of the JWS
Input is passed to the respective signing algorithms. Signing Input is passed to the respective signing algorithms.
7.1. Creating a JWS with HMAC SHA-256, HMAC SHA-384, or HMAC SHA-512 6.1. Creating a JWS with HMAC SHA-256, HMAC SHA-384, or HMAC SHA-512
Hash based Message Authentication Codes (HMACs) enable one to use a Hash based Message Authentication Codes (HMACs) enable one to use a
secret plus a cryptographic hash function to generate a Message secret plus a cryptographic hash function to generate a Message
Authentication Code (MAC). This can be used to demonstrate that the Authentication Code (MAC). This can be used to demonstrate that the
MAC matches the hashed content, in this case the JWS Signing Input, MAC matches the hashed content, in this case the JWS Signing Input,
which therefore demonstrates that whoever generated the MAC was in which therefore demonstrates that whoever generated the MAC was in
possession of the secret. The means of exchanging the shared key is possession of the secret. The means of exchanging the shared key is
outside the scope of this specification. outside the scope of this specification.
The algorithm for implementing and validating HMACs is provided in The algorithm for implementing and validating HMACs is provided in
RFC 2104 [RFC2104]. This section defines the use of the HMAC SHA- RFC 2104 [RFC2104]. This section defines the use of the HMAC SHA-
256, HMAC SHA-384, and HMAC SHA-512 cryptographic hash functions as 256, HMAC SHA-384, and HMAC SHA-512 cryptographic hash functions as
defined in FIPS 180-3 [FIPS.180-3]. The reserved "alg" header defined in FIPS 180-3 [FIPS.180-3]. The reserved "alg" header
parameter values "HS256", "HS384", and "HS512" are used in the JWS parameter values "HS256", "HS384", and "HS512" are used in the JWS
Header Input to indicate that the JWS Crypto Output contains a Header to indicate that the Encoded JWS Signature contains a
base64url encoded HMAC value using the respective hash function. base64url encoded HMAC value using the respective hash function.
The HMAC SHA-256 MAC is generated as follows: The HMAC SHA-256 MAC is generated as follows:
1. Apply the HMAC SHA-256 algorithm to the UTF-8 representation of 1. Apply the HMAC SHA-256 algorithm to the UTF-8 representation of
the JWS Signing Input using the shared key to produce an HMAC. the JWS Signing Input using the shared key to produce an HMAC.
2. Base64url encode the HMAC, as defined in this specification. 2. Base64url encode the HMAC, as defined in this specification.
The output is the JWS Crypto Output for that JWS. The output is the Encoded JWS Signature for that JWS.
The HMAC SHA-256 MAC for a JWS is validated as follows: The HMAC SHA-256 MAC for a JWS is validated as follows:
1. Apply the HMAC SHA-256 algorithm to the UTF-8 representation of 1. Apply the HMAC SHA-256 algorithm to the UTF-8 representation of
the JWS Signing Input of the JWS using the shared key. the JWS Signing Input of the JWS using the shared key.
2. Base64url encode the previously generated HMAC, as defined in 2. Base64url encode the previously generated HMAC, as defined in
this specification. this specification.
3. If the JWS Crypto Output and the previously calculated value 3. If the JWS Signature and the previously calculated value exactly
exactly match, then one has confirmation that the key was used to match, then one has confirmation that the key was used to
generate the HMAC on the JWS and that the contents of the JWS generate the HMAC on the JWS and that the contents of the JWS
have not be tampered with. have not be tampered with.
4. If the validation fails, the signed content MUST be rejected. 4. If the validation fails, the signed content MUST be rejected.
Signing with the HMAC SHA-384 and HMAC SHA-512 algorithms is Signing with the HMAC SHA-384 and HMAC SHA-512 algorithms is
performed identically to the procedure for HMAC SHA-256 - just with performed identically to the procedure for HMAC SHA-256 - just with
correspondingly longer key and result values. correspondingly longer key and result values.
7.2. Creating a JWS with RSA SHA-256, RSA SHA-384, or RSA SHA-512 6.2. Creating a JWS with RSA SHA-256, RSA SHA-384, or RSA SHA-512
This section defines the use of the RSASSA-PKCS1-v1_5 signature This section defines the use of the RSASSA-PKCS1-v1_5 signature
algorithm as defined in RFC 3447 [RFC3447], Section 8.2 (commonly algorithm as defined in RFC 3447 [RFC3447], Section 8.2 (commonly
known as PKCS#1), using SHA-256, SHA-384, or SHA-512 as the hash known as PKCS#1), using SHA-256, SHA-384, or SHA-512 as the hash
function. The RSASSA-PKCS1-v1_5 algorithm is described in FIPS 186-3 function. The RSASSA-PKCS1-v1_5 algorithm is described in FIPS 186-3
[FIPS.186-3], Section 5.5, and the SHA-256, SHA-384, and SHA-512 [FIPS.186-3], Section 5.5, and the SHA-256, SHA-384, and SHA-512
cryptographic hash functions are defined in FIPS 180-3 [FIPS.180-3]. cryptographic hash functions are defined in FIPS 180-3 [FIPS.180-3].
The reserved "alg" header parameter values "RS256", "RS384", and The reserved "alg" header parameter values "RS256", "RS384", and
"RS512" are used in the JWS Header Input to indicate that the JWS "RS512" are used in the JWS Header to indicate that the Encoded JWS
Crypto Output contains a base64url encoded RSA signature using the Signature contains a base64url encoded RSA signature using the
respective hash function. respective hash function.
The public keys employed may be retrieved using Header Parameter The public keys employed may be retrieved using Header Parameter
methods described in Section 4.1 or may be distributed using methods methods described in Section 4.1 or may be distributed using methods
that are outside the scope of this specification. that are outside the scope of this specification.
A 2048-bit or longer key length MUST be used with this algorithm. A 2048-bit or longer key length MUST be used with this algorithm.
The RSA SHA-256 signature is generated as follows: The RSA SHA-256 signature is generated as follows:
1. Generate a digital signature of the UTF-8 representation of the 1. Generate a digital signature of the UTF-8 representation of the
JWS Signing Input using RSASSA-PKCS1-V1_5-SIGN and the SHA-256 JWS Signing Input using RSASSA-PKCS1-V1_5-SIGN and the SHA-256
hash function with the desired private key. The output will be a hash function with the desired private key. The output will be a
byte array. byte array.
2. Base64url encode the byte array, as defined in this 2. Base64url encode the byte array, as defined in this
specification. specification.
The output is the JWS Crypto Output for that JWS. The output is the Encoded JWS Signature for that JWS.
The RSA SHA-256 signature for a JWS is validated as follows: The RSA SHA-256 signature for a JWS is validated as follows:
1. Take the JWS Crypto Output and base64url decode it into a byte 1. Take the Encoded JWS Signature and base64url decode it into a
array. If decoding fails, the signed content MUST be rejected. byte array. If decoding fails, the signed content MUST be
rejected.
2. Submit the UTF-8 representation of the JWS Signing Input and the 2. Submit the UTF-8 representation of the JWS Signing Input and the
public key corresponding to the private key used by the signer to public key corresponding to the private key used by the signer to
the RSASSA-PKCS1-V1_5-VERIFY algorithm using SHA-256 as the hash the RSASSA-PKCS1-V1_5-VERIFY algorithm using SHA-256 as the hash
function. function.
3. If the validation fails, the signed content MUST be rejected. 3. If the validation fails, the signed content MUST be rejected.
Signing with the RSA SHA-384 and RSA SHA-512 algorithms is performed Signing with the RSA SHA-384 and RSA SHA-512 algorithms is performed
identically to the procedure for RSA SHA-256 - just with identically to the procedure for RSA SHA-256 - just with
correspondingly longer key and result values. correspondingly longer key and result values.
7.3. Creating a JWS with ECDSA P-256 SHA-256, ECDSA P-384 SHA-384, or 6.3. Creating a JWS with ECDSA P-256 SHA-256, ECDSA P-384 SHA-384, or
ECDSA P-521 SHA-512 ECDSA P-521 SHA-512
The Elliptic Curve Digital Signature Algorithm (ECDSA) is defined by The Elliptic Curve Digital Signature Algorithm (ECDSA) is defined by
FIPS 186-3 [FIPS.186-3]. ECDSA provides for the use of Elliptic FIPS 186-3 [FIPS.186-3]. ECDSA provides for the use of Elliptic
Curve cryptography, which is able to provide equivalent security to Curve cryptography, which is able to provide equivalent security to
RSA cryptography but using shorter key lengths and with greater RSA cryptography but using shorter key lengths and with greater
processing speed. This means that ECDSA signatures will be processing speed. This means that ECDSA signatures will be
substantially smaller in terms of length than equivalently strong RSA substantially smaller in terms of length than equivalently strong RSA
Digital Signatures. Digital Signatures.
This specification defines the use of ECDSA with the P-256 curve and This specification defines the use of ECDSA with the P-256 curve and
the SHA-256 cryptographic hash function, ECDSA with the P-384 curve the SHA-256 cryptographic hash function, ECDSA with the P-384 curve
and the SHA-384 hash function, and ECDSA with the P-521 curve and the and the SHA-384 hash function, and ECDSA with the P-521 curve and the
SHA-512 hash function. The P-256, P-384, and P-521 curves are also SHA-512 hash function. The P-256, P-384, and P-521 curves are also
defined in FIPS 186-3. The reserved "alg" header parameter values defined in FIPS 186-3. The reserved "alg" header parameter values
"ES256", "ES384", and "ES512" are used in the JWS Header Input to "ES256", "ES384", and "ES512" are used in the JWS Header to indicate
indicate that the JWS Crypto Output contains a based64url encoded that the Encoded JWS Signature contains a base64url encoded ECDSA
ECDSA P-256 SHA-256, ECDSA P-384 SHA-384, or ECDSA P-521 SHA-512 P-256 SHA-256, ECDSA P-384 SHA-384, or ECDSA P-521 SHA-512 signature,
signature, respectively. respectively.
The public keys employed may be retrieved using Header Parameter The public keys employed may be retrieved using Header Parameter
methods described in Section 4.1 or may be distributed using methods methods described in Section 4.1 or may be distributed using methods
that are outside the scope of this specification. that are outside the scope of this specification.
A JWS is signed with an ECDSA P-256 SHA-256 signature as follows: A JWS is signed with an ECDSA P-256 SHA-256 signature as follows:
1. Generate a digital signature of the UTF-8 representation of the 1. Generate a digital signature of the UTF-8 representation of the
JWS Signing Input using ECDSA P-256 SHA-256 with the desired JWS Signing Input using ECDSA P-256 SHA-256 with the desired
private key. The output will be the EC point (R, S), where R and private key. The output will be the EC point (R, S), where R and
S are unsigned integers. S are unsigned integers.
2. Turn R and S into byte arrays in big endian order. Each array 2. Turn R and S into byte arrays in big endian order. Each array
will be 32 bytes long. will be 32 bytes long.
3. Concatenate the two byte arrays in the order R and then S. 3. Concatenate the two byte arrays in the order R and then S.
4. Base64url encode the 64 byte array, as defined in this 4. Base64url encode the 64 byte array, as defined in this
specification. specification.
The output is the JWS Crypto Output for the JWS. The output is the Encoded JWS Signature for the JWS.
The ECDSA P-256 SHA-256 signature for a JWS is validated as follows: The ECDSA P-256 SHA-256 signature for a JWS is validated as follows:
1. Take the JWS Crypto Output and base64url decode it into a byte 1. Take the Encoded JWS Signature and base64url decode it into a
array. If decoding fails, the signed content MUST be rejected. byte array. If decoding fails, the signed content MUST be
rejected.
2. The output of the base64url decoding MUST be a 64 byte array. 2. The output of the base64url decoding MUST be a 64 byte array.
3. Split the 64 byte array into two 32 byte arrays. The first array 3. Split the 64 byte array into two 32 byte arrays. The first array
will be R and the second S. Remember that the byte arrays are in will be R and the second S. Remember that the byte arrays are in
big endian byte order; please check the ECDSA validator in use to big endian byte order; please check the ECDSA validator in use to
see what byte order it requires. see what byte order it requires.
4. Submit the UTF-8 representation of the JWS Signing Input, R, S 4. Submit the UTF-8 representation of the JWS Signing Input, R, S
and the public key (x, y) to the ECDSA P-256 SHA-256 validator. and the public key (x, y) to the ECDSA P-256 SHA-256 validator.
skipping to change at page 16, line 14 skipping to change at page 17, line 16
digital signature instance. This means that two ECDSA digital digital signature instance. This means that two ECDSA digital
signatures using exactly the same input parameters will output signatures using exactly the same input parameters will output
different signatures because their K values will be different. The different signatures because their K values will be different. The
consequence of this is that one must validate an ECDSA signature by consequence of this is that one must validate an ECDSA signature by
submitting the previously specified inputs to an ECDSA validator. submitting the previously specified inputs to an ECDSA validator.
Signing with the ECDSA P-384 SHA-384 and ECDSA P-521 SHA-512 Signing with the ECDSA P-384 SHA-384 and ECDSA P-521 SHA-512
algorithms is performed identically to the procedure for ECDSA P-256 algorithms is performed identically to the procedure for ECDSA P-256
SHA-256 - just with correspondingly longer key and result values. SHA-256 - just with correspondingly longer key and result values.
7.4. Additional Algorithms 6.4. Additional Algorithms
Additional algorithms MAY be used to protect JWSs with corresponding Additional algorithms MAY be used to protect JWSs with corresponding
"alg" header parameter values being defined to refer to them. New "alg" header parameter values being defined to refer to them. New
"alg" header parameter values SHOULD either be defined in the IANA "alg" header parameter values SHOULD either be defined in the IANA
JSON Web Signature Algorithms registry or be a URI that contains a JSON Web Signature Algorithms registry or be a URI that contains a
collision resistant namespace. In particular, the use of algorithm collision resistant namespace. In particular, the use of algorithm
identifiers defined in XML DSIG [RFC3275] and related specifications identifiers defined in XML DSIG [RFC3275] and related specifications
is permitted. is permitted.
8. IANA Considerations 7. IANA Considerations
This specification calls for: This specification calls for:
o A new IANA registry entitled "JSON Web Signature Header o A new IANA registry entitled "JSON Web Signature Header
Parameters" for reserved header parameter names is defined in Parameters" for reserved header parameter names is defined in
Section 4.1. Inclusion in the registry is RFC Required in the RFC Section 4.1. Inclusion in the registry is RFC Required in the RFC
5226 [RFC5226] sense for reserved JWS header parameter names that 5226 [RFC5226] sense for reserved JWS header parameter names that
are intended to be interoperable between implementations. The are intended to be interoperable between implementations. The
registry will just record the reserved header parameter name and a registry will just record the reserved header parameter name and a
pointer to the RFC that defines it. This specification defines pointer to the RFC that defines it. This specification defines
inclusion of the header parameter names defined in Table 1. inclusion of the header parameter names defined in Table 1.
o A new IANA registry entitled "JSON Web Signature Algorithms" for o A new IANA registry entitled "JSON Web Signature Algorithms" for
reserved values used with the "alg" header parameter values is reserved values used with the "alg" header parameter values is
defined in Section 7.4. Inclusion in the registry is RFC Required defined in Section 6.4. Inclusion in the registry is RFC Required
in the RFC 5226 [RFC5226] sense. The registry will just record in the RFC 5226 [RFC5226] sense. The registry will just record
the "alg" value and a pointer to the RFC that defines it. This the "alg" value and a pointer to the RFC that defines it. This
specification defines inclusion of the algorithm values defined in specification defines inclusion of the algorithm values defined in
Table 3. Table 3.
9. Security Considerations 8. Security Considerations
TBD: Lots of work to do here. We need to remember to look into any TBD: Lots of work to do here. We need to remember to look into any
issues relating to security and JSON parsing. One wonders just how issues relating to security and JSON parsing. One wonders just how
secure most JSON parsing libraries are. Were they ever hardened for secure most JSON parsing libraries are. Were they ever hardened for
security scenarios? If not, what kind of holes does that open up? security scenarios? If not, what kind of holes does that open up?
Also, we need to walk through the JSON standard and see what kind of Also, we need to walk through the JSON standard and see what kind of
issues we have especially around comparison of names. For instance, issues we have especially around comparison of names. For instance,
comparisons of header parameter names and other parameters must occur comparisons of header parameter names and other parameters must occur
after they are unescaped. Need to also put in text about: Importance after they are unescaped. Need to also put in text about: Importance
of keeping secrets secret. Rotating keys. Strengths and weaknesses of keeping secrets secret. Rotating keys. Strengths and weaknesses
of the different algorithms. of the different algorithms.
TBD: Need to put in text about why strict JSON validation is TBD: Need to put in text about why strict JSON validation is
necessary. Basically, that if malformed JSON is received then the necessary. Basically, that if malformed JSON is received then the
intent of the sender is impossible to reliably discern. intent of the sender is impossible to reliably discern. One example
of malformed JSON that MUST be rejected is an object in which the
same member name occurs multiple times.
TBD: Write security considerations about the implications of using a TBD: Write security considerations about the implications of using a
SHA-1 hash (for compatibility reasons) for the "x5t" (x.509 SHA-1 hash (for compatibility reasons) for the "x5t" (x.509
certificate thumbprint). certificate thumbprint).
9.1. Unicode Comparison Security Issues When utilizing TLS to retrieve information, the authority providing
the resource MUST be authenticated and the information retrieved MUST
be free from modification.
8.1. Unicode Comparison Security Issues
Header parameter names in JWSs are Unicode strings. For security Header parameter names in JWSs are Unicode strings. For security
reasons, the representations of these names must be compared verbatim reasons, the representations of these names must be compared verbatim
after performing any escape processing (as per RFC 4627 [RFC4627], after performing any escape processing (as per RFC 4627 [RFC4627],
Section 2.5). Section 2.5).
This means, for instance, that these JSON strings must compare as This means, for instance, that these JSON strings must compare as
being equal ("sig", "\u0073ig"), whereas these must all compare as being equal ("sig", "\u0073ig"), whereas these must all compare as
being not equal to the first set or to each other ("SIG", "Sig", being not equal to the first set or to each other ("SIG", "Sig",
"si\u0047"). "si\u0047").
JSON strings MAY contain characters outside the Unicode Basic JSON strings MAY contain characters outside the Unicode Basic
Multilingual Plane. For instance, the G clef character (U+1D11E) may Multilingual Plane. For instance, the G clef character (U+1D11E) may
be represented in a JSON string as "\uD834\uDD1E". Ideally, JWS be represented in a JSON string as "\uD834\uDD1E". Ideally, JWS
implementations SHOULD ensure that characters outside the Basic implementations SHOULD ensure that characters outside the Basic
Multilingual Plane are preserved and compared correctly; Multilingual Plane are preserved and compared correctly;
alternatively, if this is not possible due to these characters alternatively, if this is not possible due to these characters
exercising limitations present in the underlying JSON implementation, exercising limitations present in the underlying JSON implementation,
then input containing them MUST be rejected. then input containing them MUST be rejected.
10. Open Issues and Things To Be Done (TBD) 9. Open Issues and Things To Be Done (TBD)
The following items remain to be done in this draft (and related The following items remain to be done in this draft:
drafts):
o Consider whether there is a better term than "Digital Signature" o Consider whether there is a better term than "Digital Signature"
for the concept that includes both HMACs and digital signatures for the concept that includes both HMACs and digital signatures
using public keys. using public keys.
o Consider whether we really want to allow private header parameter o Consider whether we really want to allow private header parameter
names that are not registered with IANA and are not in collision- names that are not registered with IANA and are not in collision-
resistant namespaces. Eventually this could result in interop resistant namespaces. Eventually this could result in interop
nightmares where you need to have different code to talk to nightmares where you need to have different code to talk to
different endpoints that "knows" about each endpoint's private different endpoints that "knows" about each endpoint's private
skipping to change at page 18, line 37 skipping to change at page 19, line 45
o Since RFC 3447 Section 8 explicitly calls for people NOT to adopt o Since RFC 3447 Section 8 explicitly calls for people NOT to adopt
RSASSA-PKCS1 for new applications and instead requests that people RSASSA-PKCS1 for new applications and instead requests that people
transition to RSASSA-PSS, we probably need some Security transition to RSASSA-PSS, we probably need some Security
Considerations text explaining why RSASSA-PKCS1 is being used Considerations text explaining why RSASSA-PKCS1 is being used
(it's what's commonly implemented) and what the potential (it's what's commonly implemented) and what the potential
consequences are. consequences are.
o Add Security Considerations text on timing attacks. o Add Security Considerations text on timing attacks.
o It would be good to have a confirmation method element so it could
be used with holder-of-key.
o Think about how to best describe the concept currently described
as "the bytes of the UTF-8 representation of". Possible terms to
use instead of "bytes of" include "byte sequence", "octet series",
and "octet sequence". Also consider whether we want to add an
overall clarifying statement somewhere in each spec something like
"every place we say 'the UTF-8 representation of X', we mean 'the
bytes of the UTF-8 representation of X'". That would potentially
allow us to omit the "the bytes of" part everywhere else.
o Consider whether a media type should be proposed, such as
"application/jws".
o Finish the Security Considerations section. o Finish the Security Considerations section.
o Sort out what to do with the IANA registries if this is first o Add an example in which the payload is not a base64url encoded
standardized as an OpenID specification. JSON object.
o Finish the companion encryption specification, per the agreements o Consider having an algorithm that is a MAC using SHA-256 that
documented at http://self-issued.info/?p=378. provides content integrity but for which there is no associated
secret. This would be like the JWT "alg":"none", in that no
validation of the authenticity content is provided, but with a
checksum provided.
11. References o Consider whether to define the JWT "alg":"none" here, rather than
in the JWT spec.
11.1. Normative References 10. References
10.1. Normative References
[FIPS.180-3] [FIPS.180-3]
National Institute of Standards and Technology, "Secure National Institute of Standards and Technology, "Secure
Hash Standard (SHS)", FIPS PUB 180-3, October 2008. Hash Standard (SHS)", FIPS PUB 180-3, October 2008.
[FIPS.186-3] [FIPS.186-3]
National Institute of Standards and Technology, "Digital National Institute of Standards and Technology, "Digital
Signature Standard (DSS)", FIPS PUB 186-3, June 2009. Signature Standard (DSS)", FIPS PUB 186-3, June 2009.
[JWK] Jones, M., "JSON Web Key (JWK)", April 2011. [JWK] Jones, M., "JSON Web Key (JWK)", October 2011.
[JWT] Jones, M., Balfanz, D., Bradley, J., Goland, Y., Panzer,
J., Sakimura, N., and P. Tarjan, "JSON Web Token (JWT)",
March 2011.
[RFC1421] Linn, J., "Privacy Enhancement for Internet Electronic [RFC1421] Linn, J., "Privacy Enhancement for Internet Electronic
Mail: Part I: Message Encryption and Authentication Mail: Part I: Message Encryption and Authentication
Procedures", RFC 1421, February 1993. Procedures", RFC 1421, February 1993.
[RFC1738] Berners-Lee, T., Masinter, L., and M. McCahill, "Uniform [RFC1738] Berners-Lee, T., Masinter, L., and M. McCahill, "Uniform
Resource Locators (URL)", RFC 1738, December 1994. Resource Locators (URL)", RFC 1738, December 1994.
[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail [RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message Extensions (MIME) Part One: Format of Internet Message
Bodies", RFC 2045, November 1996. Bodies", RFC 2045, November 1996.
[RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed- [RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
Hashing for Message Authentication", RFC 2104, Hashing for Message Authentication", RFC 2104,
February 1997. February 1997.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.
[RFC3339] Klyne, G., Ed. and C. Newman, "Date and Time on the [RFC3339] Klyne, G., Ed. and C. Newman, "Date and Time on the
Internet: Timestamps", RFC 3339, July 2002. Internet: Timestamps", RFC 3339, July 2002.
[RFC3447] Jonsson, J. and B. Kaliski, "Public-Key Cryptography [RFC3447] Jonsson, J. and B. Kaliski, "Public-Key Cryptography
Standards (PKCS) #1: RSA Cryptography Specifications Standards (PKCS) #1: RSA Cryptography Specifications
Version 2.1", RFC 3447, February 2003. Version 2.1", RFC 3447, February 2003.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, November 2003. 10646", STD 63, RFC 3629, November 2003.
skipping to change at page 20, line 9 skipping to change at page 21, line 36
[RFC4627] Crockford, D., "The application/json Media Type for [RFC4627] Crockford, D., "The application/json Media Type for
JavaScript Object Notation (JSON)", RFC 4627, July 2006. JavaScript Object Notation (JSON)", RFC 4627, July 2006.
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, October 2006. Encodings", RFC 4648, October 2006.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226, IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008. May 2008.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, May 2008. (CRL) Profile", RFC 5280, May 2008.
[RFC5785] Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known [RFC5785] Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known
Uniform Resource Identifiers (URIs)", RFC 5785, Uniform Resource Identifiers (URIs)", RFC 5785,
April 2010. April 2010.
[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and
Verification of Domain-Based Application Service Identity
within Internet Public Key Infrastructure Using X.509
(PKIX) Certificates in the Context of Transport Layer
Security (TLS)", RFC 6125, March 2011.
[USA15] Davis, M., Whistler, K., and M. Duerst, "Unicode [USA15] Davis, M., Whistler, K., and M. Duerst, "Unicode
Normalization Forms", Unicode Standard Annex 15, 09 2009. Normalization Forms", Unicode Standard Annex 15, 09 2009.
11.2. Informative References 10.2. Informative References
[CanvasApp] [CanvasApp]
Facebook, "Canvas Applications", 2010. Facebook, "Canvas Applications", 2010.
[JCA] Oracle, "Java Cryptography Architecture", 2011. [JCA] Oracle, "Java Cryptography Architecture", 2011.
[JSS] Bradley, J. and N. Sakimura (editor), "JSON Simple Sign", [JSS] Bradley, J. and N. Sakimura (editor), "JSON Simple Sign",
September 2010. September 2010.
[JWE] Jones, M., Bradley, J., and N. Sakimura, "JSON Web [JWE] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
Encryption (JWE)", March 2011. Encryption (JWE)", October 2011.
[JWT] Jones, M., Balfanz, D., Bradley, J., Goland, Y., Panzer,
J., Sakimura, N., and P. Tarjan, "JSON Web Token (JWT)",
October 2011.
[MagicSignatures] [MagicSignatures]
Panzer (editor), J., Laurie, B., and D. Balfanz, "Magic Panzer (editor), J., Laurie, B., and D. Balfanz, "Magic
Signatures", August 2010. Signatures", August 2010.
[RFC3275] Eastlake, D., Reagle, J., and D. Solo, "(Extensible Markup [RFC3275] Eastlake, D., Reagle, J., and D. Solo, "(Extensible Markup
Language) XML-Signature Syntax and Processing", RFC 3275, Language) XML-Signature Syntax and Processing", RFC 3275,
March 2002. March 2002.
Appendix A. JWS Examples Appendix A. JWS Examples
skipping to change at page 21, line 4 skipping to change at page 22, line 41
Language) XML-Signature Syntax and Processing", RFC 3275, Language) XML-Signature Syntax and Processing", RFC 3275,
March 2002. March 2002.
Appendix A. JWS Examples Appendix A. JWS Examples
This section provides several examples of JWSs. While these examples This section provides several examples of JWSs. While these examples
all represent JSON Web Tokens (JWTs) [JWT], the payload can be any all represent JSON Web Tokens (JWTs) [JWT], the payload can be any
base64url encoded content. base64url encoded content.
A.1. JWS using HMAC SHA-256 A.1. JWS using HMAC SHA-256
A.1.1. Encoding A.1.1. Encoding
The following example JSON header object declares that the data The following example JWS Header declares that the data structure is
structure is a JSON Web Token (JWT) [JWT] and the JWS Signing Input a JSON Web Token (JWT) [JWT] and the JWS Signing Input is signed
is signed using the HMAC SHA-256 algorithm. Note that white space is using the HMAC SHA-256 algorithm. Note that white space is
explicitly allowed in Decoded JWS Header Input strings and no explicitly allowed in JWS Header strings and no canonicalization is
canonicalization is performed before encoding. performed before encoding.
{"typ":"JWT", {"typ":"JWT",
"alg":"HS256"} "alg":"HS256"}
The following byte array contains the UTF-8 characters for the The following byte array contains the UTF-8 characters for the JWS
Decoded JWS Header Input: Header:
[123, 34, 116, 121, 112, 34, 58, 34, 74, 87, 84, 34, 44, 13, 10, 32, [123, 34, 116, 121, 112, 34, 58, 34, 74, 87, 84, 34, 44, 13, 10, 32,
34, 97, 108, 103, 34, 58, 34, 72, 83, 50, 53, 54, 34, 125] 34, 97, 108, 103, 34, 58, 34, 72, 83, 50, 53, 54, 34, 125]
Base64url encoding this UTF-8 representation yields this JWS Header Base64url encoding this UTF-8 representation yields this Encoded JWS
Input value: Header value:
eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9 eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9
The Decoded JWS Payload Input used in this example follows. (Note The JWS Payload used in this example follows. (Note that the payload
that the payload can be any base64url encoded content, and need not can be any base64url encoded content, and need not be a base64url
be a base64url encoded JSON object.) encoded JSON object.)
{"iss":"joe", {"iss":"joe",
"exp":1300819380, "exp":1300819380,
"http://example.com/is_root":true} "http://example.com/is_root":true}
The following byte array contains the UTF-8 characters for the The following byte array contains the UTF-8 characters for the JWS
Decoded JWS Payload Input: Payload:
[123, 34, 105, 115, 115, 34, 58, 34, 106, 111, 101, 34, 44, 13, 10, [123, 34, 105, 115, 115, 34, 58, 34, 106, 111, 101, 34, 44, 13, 10,
32, 34, 101, 120, 112, 34, 58, 49, 51, 48, 48, 56, 49, 57, 51, 56, 32, 34, 101, 120, 112, 34, 58, 49, 51, 48, 48, 56, 49, 57, 51, 56,
48, 44, 13, 10, 32, 34, 104, 116, 116, 112, 58, 47, 47, 101, 120, 97, 48, 44, 13, 10, 32, 34, 104, 116, 116, 112, 58, 47, 47, 101, 120, 97,
109, 112, 108, 101, 46, 99, 111, 109, 47, 105, 115, 95, 114, 111, 109, 112, 108, 101, 46, 99, 111, 109, 47, 105, 115, 95, 114, 111,
111, 116, 34, 58, 116, 114, 117, 101, 125] 111, 116, 34, 58, 116, 114, 117, 101, 125]
Base64url encoding the above yields the JWS Payload Input value: Base64url encoding the above yields the Encoded JWS Payload value:
eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ
Concatenating the JWS Header Input, a period character, and the JWS Concatenating the Encoded JWS Header, a period character, and the
Payload Input yields this JWS Signing Input value (with line breaks Encoded JWS Payload yields this JWS Signing Input value (with line
for display purposes only): breaks for display purposes only):
eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9 eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9
. .
eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ
The UTF-8 representation of the JWS Signing Input is the following The UTF-8 representation of the JWS Signing Input is the following
byte array: byte array:
[101, 121, 74, 48, 101, 88, 65, 105, 79, 105, 74, 75, 86, 49, 81, [101, 121, 74, 48, 101, 88, 65, 105, 79, 105, 74, 75, 86, 49, 81,
105, 76, 65, 48, 75, 73, 67, 74, 104, 98, 71, 99, 105, 79, 105, 74, 105, 76, 65, 48, 75, 73, 67, 74, 104, 98, 71, 99, 105, 79, 105, 74,
73, 85, 122, 73, 49, 78, 105, 74, 57, 46, 101, 121, 74, 112, 99, 51, 73, 85, 122, 73, 49, 78, 105, 74, 57, 46, 101, 121, 74, 112, 99, 51,
skipping to change at page 22, line 14 skipping to change at page 24, line 4
[101, 121, 74, 48, 101, 88, 65, 105, 79, 105, 74, 75, 86, 49, 81, [101, 121, 74, 48, 101, 88, 65, 105, 79, 105, 74, 75, 86, 49, 81,
105, 76, 65, 48, 75, 73, 67, 74, 104, 98, 71, 99, 105, 79, 105, 74, 105, 76, 65, 48, 75, 73, 67, 74, 104, 98, 71, 99, 105, 79, 105, 74,
73, 85, 122, 73, 49, 78, 105, 74, 57, 46, 101, 121, 74, 112, 99, 51, 73, 85, 122, 73, 49, 78, 105, 74, 57, 46, 101, 121, 74, 112, 99, 51,
77, 105, 79, 105, 74, 113, 98, 50, 85, 105, 76, 65, 48, 75, 73, 67, 77, 105, 79, 105, 74, 113, 98, 50, 85, 105, 76, 65, 48, 75, 73, 67,
74, 108, 101, 72, 65, 105, 79, 106, 69, 122, 77, 68, 65, 52, 77, 84, 74, 108, 101, 72, 65, 105, 79, 106, 69, 122, 77, 68, 65, 52, 77, 84,
107, 122, 79, 68, 65, 115, 68, 81, 111, 103, 73, 109, 104, 48, 100, 107, 122, 79, 68, 65, 115, 68, 81, 111, 103, 73, 109, 104, 48, 100,
72, 65, 54, 76, 121, 57, 108, 101, 71, 70, 116, 99, 71, 120, 108, 76, 72, 65, 54, 76, 121, 57, 108, 101, 71, 70, 116, 99, 71, 120, 108, 76,
109, 78, 118, 98, 83, 57, 112, 99, 49, 57, 121, 98, 50, 57, 48, 73, 109, 78, 118, 98, 83, 57, 112, 99, 49, 57, 121, 98, 50, 57, 48, 73,
106, 112, 48, 99, 110, 86, 108, 102, 81] 106, 112, 48, 99, 110, 86, 108, 102, 81]
HMACs are generated using keys. This example uses the key HMACs are generated using keys. This example uses the key
represented by the following byte array: represented by the following byte array:
[3, 35, 53, 75, 43, 15, 165, 188, 131, 126, 6, 101, 119, 123, 166, [3, 35, 53, 75, 43, 15, 165, 188, 131, 126, 6, 101, 119, 123, 166,
143, 90, 179, 40, 230, 240, 84, 201, 40, 169, 15, 132, 178, 210, 80, 143, 90, 179, 40, 230, 240, 84, 201, 40, 169, 15, 132, 178, 210, 80,
46, 191, 211, 251, 90, 146, 210, 6, 71, 239, 150, 138, 180, 195, 119, 46, 191, 211, 251, 90, 146, 210, 6, 71, 239, 150, 138, 180, 195, 119,
98, 61, 34, 61, 46, 33, 114, 5, 46, 79, 8, 192, 205, 154, 245, 103, 98, 61, 34, 61, 46, 33, 114, 5, 46, 79, 8, 192, 205, 154, 245, 103,
208, 128, 163] 208, 128, 163]
Running the HMAC SHA-256 algorithm on the UTF-8 representation of the Running the HMAC SHA-256 algorithm on the UTF-8 representation of the
JWS Signing Input with this key yields the following byte array: JWS Signing Input with this key yields the following byte array:
[116, 24, 223, 180, 151, 153, 224, 37, 79, 250, 96, 125, 216, 173, [116, 24, 223, 180, 151, 153, 224, 37, 79, 250, 96, 125, 216, 173,
187, 186, 22, 212, 37, 77, 105, 214, 191, 240, 91, 88, 5, 88, 83, 187, 186, 22, 212, 37, 77, 105, 214, 191, 240, 91, 88, 5, 88, 83,
132, 141, 121] 132, 141, 121]
Base64url encoding the above HMAC output yields the JWS Crypto Output Base64url encoding the above HMAC output yields the Encoded JWS
value: Signature value:
dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk
A.1.2. Decoding A.1.2. Decoding
Decoding the JWS first requires removing the base64url encoding from Decoding the JWS first requires removing the base64url encoding from
the JWS Header Input, the JWS Payload Input, and the JWS Crypto the Encoded JWS Header, the Encoded JWS Payload, and the Encoded JWS
Output. We base64url decode the inputs per Section 6 and turn them Signature. We base64url decode the inputs and turn them into the
into the corresponding byte arrays. We translate the header input corresponding byte arrays. We translate the header input byte array
byte array containing UTF-8 encoded characters into the Decoded JWS containing UTF-8 encoded characters into the JWS Header string.
Header Input string.
A.1.3. Validating A.1.3. Validating
Next we validate the decoded results. Since the "alg" parameter in Next we validate the decoded results. Since the "alg" parameter in
the header is "HS256", we validate the HMAC SHA-256 signature the header is "HS256", we validate the HMAC SHA-256 signature
contained in the JWS Crypto Output. If any of the validation steps contained in the JWS Signature. If any of the validation steps fail,
fail, the signed content MUST be rejected. the signed content MUST be rejected.
First, we validate that the decoded JWS Header Input string is legal First, we validate that the JWS Header string is legal JSON.
JSON.
To validate the signature, we repeat the previous process of using To validate the signature, we repeat the previous process of using
the correct key and the UTF-8 representation of the JWS Signing Input the correct key and the UTF-8 representation of the JWS Signing Input
as input to a SHA-256 HMAC function and then taking the output and as input to a SHA-256 HMAC function and then taking the output and
determining if it matches the Decoded JWS Crypto Output. If it determining if it matches the JWS Signature. If it matches exactly,
matches exactly, the signature has been validated. the signature has been validated.
A.2. JWS using RSA SHA-256 A.2. JWS using RSA SHA-256
A.2.1. Encoding A.2.1. Encoding
The Decoded JWS Header Input in this example is different from the The JWS Header in this example is different from the previous example
previous example in two ways: First, because a different algorithm is in two ways: First, because a different algorithm is being used, the
being used, the "alg" value is different. Second, for illustration "alg" value is different. Second, for illustration purposes only,
purposes only, the optional "typ" parameter is not used. (This the optional "typ" parameter is not used. (This difference is not
difference is not related to the signature algorithm employed.) The related to the signature algorithm employed.) The JWS Header used
Decoded JWS Header Input used is: is:
{"alg":"RS256"} {"alg":"RS256"}
The following byte array contains the UTF-8 characters for the The following byte array contains the UTF-8 characters for the JWS
Decoded JWS Header Input: Header:
[123, 34, 97, 108, 103, 34, 58, 34, 82, 83, 50, 53, 54, 34, 125] [123, 34, 97, 108, 103, 34, 58, 34, 82, 83, 50, 53, 54, 34, 125]
Base64url encoding this UTF-8 representation yields this JWS Header Base64url encoding this UTF-8 representation yields this Encoded JWS
Input value: Header value:
eyJhbGciOiJSUzI1NiJ9 eyJhbGciOiJSUzI1NiJ9
The Decoded JWS Payload Input used in this example, which follows, is The JWS Payload used in this example, which follows, is the same as
the same as in the previous example. Since the JWS Payload Input in the previous example. Since the Encoded JWS Payload will
will therefore be the same, its computation is not repeated here. therefore be the same, its computation is not repeated here.
{"iss":"joe", {"iss":"joe",
"exp":1300819380, "exp":1300819380,
"http://example.com/is_root":true} "http://example.com/is_root":true}
Concatenating the JWS Header Input, a period character, and the JWS Concatenating the Encoded JWS Header, a period character, and the
Payload Input yields this JWS Signing Input value (with line breaks Encoded JWS Payload yields this JWS Signing Input value (with line
for display purposes only): breaks for display purposes only):
eyJhbGciOiJSUzI1NiJ9 eyJhbGciOiJSUzI1NiJ9
. .
eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ
The UTF-8 representation of the JWS Signing Input is the following The UTF-8 representation of the JWS Signing Input is the following
byte array: byte array:
[101, 121, 74, 104, 98, 71, 99, 105, 79, 105, 74, 83, 85, 122, 73, [101, 121, 74, 104, 98, 71, 99, 105, 79, 105, 74, 83, 85, 122, 73,
49, 78, 105, 74, 57, 46, 101, 121, 74, 112, 99, 51, 77, 105, 79, 105, 49, 78, 105, 74, 57, 46, 101, 121, 74, 112, 99, 51, 77, 105, 79, 105,
74, 113, 98, 50, 85, 105, 76, 65, 48, 75, 73, 67, 74, 108, 101, 72, 74, 113, 98, 50, 85, 105, 76, 65, 48, 75, 73, 67, 74, 108, 101, 72,
skipping to change at page 26, line 33 skipping to change at page 28, line 33
| | 46, 176, 47, 158, 58, 65, 214, 18, 202, 173, 21, 145, | | | 46, 176, 47, 158, 58, 65, 214, 18, 202, 173, 21, 145, |
| | 18, 115, 160, 95, 35, 185, 232, 56, 250, 175, 132, 157, | | | 18, 115, 160, 95, 35, 185, 232, 56, 250, 175, 132, 157, |
| | 105, 132, 41, 239, 90, 30, 136, 121, 130, 54, 195, 212, | | | 105, 132, 41, 239, 90, 30, 136, 121, 130, 54, 195, 212, |
| | 14, 96, 69, 34, 165, 68, 200, 242, 122, 122, 45, 184, 6, | | | 14, 96, 69, 34, 165, 68, 200, 242, 122, 122, 45, 184, 6, |
| | 99, 209, 108, 247, 202, 234, 86, 222, 64, 92, 178, 33, | | | 99, 209, 108, 247, 202, 234, 86, 222, 64, 92, 178, 33, |
| | 90, 69, 178, 194, 85, 102, 181, 90, 193, 167, 72, 160, | | | 90, 69, 178, 194, 85, 102, 181, 90, 193, 167, 72, 160, |
| | 112, 223, 200, 163, 42, 70, 149, 67, 208, 25, 238, 251, | | | 112, 223, 200, 163, 42, 70, 149, 67, 208, 25, 238, 251, |
| | 71] | | | 71] |
+--------+----------------------------------------------------------+ +--------+----------------------------------------------------------+
Base64url encoding the signature produces this value for the JWS Base64url encoding the signature produces this value for the Encoded
Crypto Output: JWS Signature:
cC4hiUPoj9Eetdgtv3hF80EGrhuB__dzERat0XF9g2VtQgr9PJbu3XOiZj5RZmh7AAuHIm4Bh-0Qc_lF5YKt_O8W2Fp5jujGbds9uJdbF9CUAr7t1dnZcAcQjbKBYNX4BAynRFdiuB--f_nZLgrnbyTyWzO75vRK5h6xBArLIARNPvkSjtQBMHlb1L07Qe7K0GarZRmB_eSN9383LcOLn6_dO--xi12jzDwusC-eOkHWEsqtFZESc6BfI7noOPqvhJ1phCnvWh6IeYI2w9QOYEUipUTI8np6LbgGY9Fs98rqVt5AXLIhWkWywlVmtVrBp0igcN_IoypGlUPQGe77Rw cC4hiUPoj9Eetdgtv3hF80EGrhuB__dzERat0XF9g2VtQgr9PJbu3XOiZj5RZmh7AAuHIm4Bh-0Qc_lF5YKt_O8W2Fp5jujGbds9uJdbF9CUAr7t1dnZcAcQjbKBYNX4BAynRFdiuB--f_nZLgrnbyTyWzO75vRK5h6xBArLIARNPvkSjtQBMHlb1L07Qe7K0GarZRmB_eSN9383LcOLn6_dO--xi12jzDwusC-eOkHWEsqtFZESc6BfI7noOPqvhJ1phCnvWh6IeYI2w9QOYEUipUTI8np6LbgGY9Fs98rqVt5AXLIhWkWywlVmtVrBp0igcN_IoypGlUPQGe77Rw
A.2.2. Decoding A.2.2. Decoding
Decoding the JWS from this example requires processing the JWS Header Decoding the JWS from this example requires processing the Encoded
Input and JWS Payload Input exactly as done in the first example. JWS Header and Encoded JWS Payload exactly as done in the first
example.
A.2.3. Validating A.2.3. Validating
Since the "alg" parameter in the header is "RS256", we validate the Since the "alg" parameter in the header is "RS256", we validate the
RSA SHA-256 signature contained in the JWS Crypto Output. If any of RSA SHA-256 signature contained in the JWS Signature. If any of the
the validation steps fail, the signed content MUST be rejected. validation steps fail, the signed content MUST be rejected.
First, we validate that the decoded JWS Header Input string is legal First, we validate that the JWS Header string is legal JSON.
JSON.
Validating the JWS Crypto Output is a little different from the Validating the JWS Signature is a little different from the previous
previous example. First, we base64url decode the JWS Crypto Output example. First, we base64url decode the Encoded JWS Signature to
to produce a signature S to check. We then pass (n, e), S and the produce a signature S to check. We then pass (n, e), S and the UTF-8
UTF-8 representation of the JWS Signing Input to an RSA signature representation of the JWS Signing Input to an RSA signature verifier
verifier that has been configured to use the SHA-256 hash function. that has been configured to use the SHA-256 hash function.
A.3. JWS using ECDSA P-256 SHA-256 A.3. JWS using ECDSA P-256 SHA-256
A.3.1. Encoding A.3.1. Encoding
The Decoded JWS Header Input for this example differs from the The JWS Header for this example differs from the previous example
previous example because a different algorithm is being used. The because a different algorithm is being used. The JWS Header used is:
Decoded JWS Header Input used is:
{"alg":"ES256"} {"alg":"ES256"}
The following byte array contains the UTF-8 characters for the The following byte array contains the UTF-8 characters for the JWS
Decoded JWS Header Input: Header:
[123, 34, 97, 108, 103, 34, 58, 34, 69, 83, 50, 53, 54, 34, 125] [123, 34, 97, 108, 103, 34, 58, 34, 69, 83, 50, 53, 54, 34, 125]
Base64url encoding this UTF-8 representation yields this JWS Header Base64url encoding this UTF-8 representation yields this Encoded JWS
Input value: Header value:
eyJhbGciOiJFUzI1NiJ9 eyJhbGciOiJFUzI1NiJ9
The Decoded JWS Payload Input used in this example, which follows, is The JWS Payload used in this example, which follows, is the same as
the same as in the previous examples. Since the JWS Payload Input in the previous examples. Since the Encoded JWS Payload will
will therefore be the same, its computation is not repeated here. therefore be the same, its computation is not repeated here.
{"iss":"joe", {"iss":"joe",
"exp":1300819380, "exp":1300819380,
"http://example.com/is_root":true} "http://example.com/is_root":true}
Concatenating the JWS Header Input, a period character, and the JWS Concatenating the Encoded JWS Header, a period character, and the
Payload Input yields this JWS Signing Input value (with line breaks Encoded JWS Payload yields this JWS Signing Input value (with line
for display purposes only): breaks for display purposes only):
eyJhbGciOiJFUzI1NiJ9 eyJhbGciOiJFUzI1NiJ9
. .
eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ
The UTF-8 representation of the JWS Signing Input is the following The UTF-8 representation of the JWS Signing Input is the following
byte array: byte array:
[101, 121, 74, 104, 98, 71, 99, 105, 79, 105, 74, 70, 85, 122, 73, [101, 121, 74, 104, 98, 71, 99, 105, 79, 105, 74, 70, 85, 122, 73,
49, 78, 105, 74, 57, 46, 101, 121, 74, 112, 99, 51, 77, 105, 79, 105, 49, 78, 105, 74, 57, 46, 101, 121, 74, 112, 99, 51, 77, 105, 79, 105,
74, 113, 98, 50, 85, 105, 76, 65, 48, 75, 73, 67, 74, 108, 101, 72, 74, 113, 98, 50, 85, 105, 76, 65, 48, 75, 73, 67, 74, 108, 101, 72,
skipping to change at page 28, line 43 skipping to change at page 30, line 42
+--------+----------------------------------------------------------+ +--------+----------------------------------------------------------+
| R | [14, 209, 33, 83, 121, 99, 108, 72, 60, 47, 127, 21, 88, | | R | [14, 209, 33, 83, 121, 99, 108, 72, 60, 47, 127, 21, 88, |
| | 7, 212, 2, 163, 178, 40, 3, 58, 249, 124, 126, 23, 129, | | | 7, 212, 2, 163, 178, 40, 3, 58, 249, 124, 126, 23, 129, |
| | 154, 195, 22, 158, 166, 101] | | | 154, 195, 22, 158, 166, 101] |
| S | [197, 10, 7, 211, 140, 60, 112, 229, 216, 241, 45, 175, | | S | [197, 10, 7, 211, 140, 60, 112, 229, 216, 241, 45, 175, |
| | 8, 74, 84, 128, 166, 101, 144, 197, 242, 147, 80, 154, | | | 8, 74, 84, 128, 166, 101, 144, 197, 242, 147, 80, 154, |
| | 143, 63, 127, 138, 131, 163, 84, 213] | | | 143, 63, 127, 138, 131, 163, 84, 213] |
+--------+----------------------------------------------------------+ +--------+----------------------------------------------------------+
Concatenating the S array to the end of the R array and base64url Concatenating the S array to the end of the R array and base64url
encoding the result produces this value for the JWS Crypto Output: encoding the result produces this value for the Encoded JWS
Signature:
DtEhU3ljbEg8L38VWAfUAqOyKAM6-Xx-F4GawxaepmXFCgfTjDxw5djxLa8ISlSApmWQxfKTUJqPP3-Kg6NU1Q DtEhU3ljbEg8L38VWAfUAqOyKAM6-Xx-F4GawxaepmXFCgfTjDxw5djxLa8ISlSApmWQxfKTUJqPP3-Kg6NU1Q
A.3.2. Decoding A.3.2. Decoding
Decoding the JWS from this example requires processing the JWS Header Decoding the JWS from this example requires processing the Encoded
Input and JWS Payload Input exactly as done in the first example. JWS Header and Encoded JWS Payload exactly as done in the first
example.
A.3.3. Validating A.3.3. Validating
Since the "alg" parameter in the header is "ES256", we validate the Since the "alg" parameter in the header is "ES256", we validate the
ECDSA P-256 SHA-256 signature contained in the JWS Crypto Output. If ECDSA P-256 SHA-256 signature contained in the JWS Signature. If any
any of the validation steps fail, the signed content MUST be of the validation steps fail, the signed content MUST be rejected.
rejected.
First, we validate that the decoded JWS Header Input string is legal First, we validate that the JWS Header string is legal JSON.
JSON.
Validating the JWS Crypto Output is a little different from the first Validating the JWS Signature is a little different from the first
example. First, we base64url decode the JWS Crypto Output as in the example. First, we base64url decode the Encoded JWS Signature as in
previous examples but we then need to split the 64 member byte array the previous examples but we then need to split the 64 member byte
that must result into two 32 byte arrays, the first R and the second array that must result into two 32 byte arrays, the first R and the
S. We then pass (x, y), (R, S) and the UTF-8 representation of the second S. We then pass (x, y), (R, S) and the UTF-8 representation of
JWS Signing Input to an ECDSA signature verifier that has been the JWS Signing Input to an ECDSA signature verifier that has been
configured to use the P-256 curve with the SHA-256 hash function. configured to use the P-256 curve with the SHA-256 hash function.
As explained in Section 7.3, the use of the k value in ECDSA means As explained in Section 6.3, the use of the k value in ECDSA means
that we cannot validate the correctness of the signature in the same that we cannot validate the correctness of the signature in the same
way we validated the correctness of the HMAC. Instead, way we validated the correctness of the HMAC. Instead,
implementations MUST use an ECDSA validator to validate the implementations MUST use an ECDSA validator to validate the
signature. signature.
Appendix B. Algorithm Identifier Cross-Reference Appendix B. Algorithm Identifier Cross-Reference
This appendix contains a table cross-referencing the "alg" values This appendix contains a table cross-referencing the "alg" values
used in this specification with the equivalent identifiers used by used in this specification with the equivalent identifiers used by
other standards and software packages. See XML DSIG [RFC3275] and other standards and software packages. See XML DSIG [RFC3275] and
skipping to change at page 33, line 7 skipping to change at page 35, line 7
A-z_4ME A-z_4ME
Appendix D. Acknowledgements Appendix D. Acknowledgements
Solutions for signing JSON content were previously explored by Magic Solutions for signing JSON content were previously explored by Magic
Signatures [MagicSignatures], JSON Simple Sign [JSS], and Canvas Signatures [MagicSignatures], JSON Simple Sign [JSS], and Canvas
Applications [CanvasApp], all of which influenced this draft. Applications [CanvasApp], all of which influenced this draft.
Appendix E. Document History Appendix E. Document History
-03
o Simplified terminology to better match JWE, where the terms "JWS
Header" and "Encoded JWS Header", are now used, for instance,
rather than the previous terms "Decoded JWS Header Input" and "JWS
Header Input". Likewise the terms "JWS Payload" and "JWS
Signature" are now used, rather than "JWS Payload Input" and "JWS
Crypto Output".
o The "jku" and "x5u" URLs are now required to be absolute URLs.
o Removed this unnecessary language from the "kid" description:
"Omitting this parameter is equivalent to setting it to an empty
string".
o Changed StringAndURI to StringOrURI.
-02 -02
o Reference the JSON Web Key (JWK) specification from the "jku" o Reference the JSON Web Key (JWK) specification from the "jku"
header parameter. header parameter.
-01 -01
o Changed RSA SHA-256 from MUST be supported to RECOMMENDED that it o Changed RSA SHA-256 from MUST be supported to RECOMMENDED that it
be supported. Rationale: Several people have objected to the be supported. Rationale: Several people have objected to the
requirement for implementing RSA SHA-256, some because they will requirement for implementing RSA SHA-256, some because they will
 End of changes. 114 change blocks. 
367 lines changed or deleted 427 lines changed or added

This html diff was produced by rfcdiff 1.48. The latest version is available from http://tools.ietf.org/tools/rfcdiff/