JOSE Working Group M. Jones
Internet-Draft Microsoft
Intended status: Standards Track J. Bradley
Expires: January 5, 2015 Ping Identity
N. Sakimura
NRI
July 4, 2014
JSON Web Signature (JWS)
draft-ietf-jose-json-web-signature-31
Abstract
JSON Web Signature (JWS) represents content secured with digital
signatures or Message Authentication Codes (MACs) using JavaScript
Object Notation (JSON) based data structures. Cryptographic
algorithms and identifiers for use with this specification are
described in the separate JSON Web Algorithms (JWA) specification and
an IANA registry defined by that specification. Related encryption
capabilities are described in the separate JSON Web Encryption (JWE)
specification.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 5, 2015.
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
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publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Notational Conventions . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. JSON Web Signature (JWS) Overview . . . . . . . . . . . . . . 6
3.1. JWS Compact Serialization Overview . . . . . . . . . . . . 7
3.2. JWS JSON Serialization Overview . . . . . . . . . . . . . 7
3.3. Example JWS . . . . . . . . . . . . . . . . . . . . . . . 8
4. JOSE Header . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1. Registered Header Parameter Names . . . . . . . . . . . . 10
4.1.1. "alg" (Algorithm) Header Parameter . . . . . . . . . . 10
4.1.2. "jku" (JWK Set URL) Header Parameter . . . . . . . . . 10
4.1.3. "jwk" (JSON Web Key) Header Parameter . . . . . . . . 10
4.1.4. "kid" (Key ID) Header Parameter . . . . . . . . . . . 11
4.1.5. "x5u" (X.509 URL) Header Parameter . . . . . . . . . . 11
4.1.6. "x5c" (X.509 Certificate Chain) Header Parameter . . . 11
4.1.7. "x5t" (X.509 Certificate SHA-1 Thumbprint) Header
Parameter . . . . . . . . . . . . . . . . . . . . . . 12
4.1.8. "x5t#S256" (X.509 Certificate SHA-256 Thumbprint)
Header Parameter . . . . . . . . . . . . . . . . . . . 12
4.1.9. "typ" (Type) Header Parameter . . . . . . . . . . . . 12
4.1.10. "cty" (Content Type) Header Parameter . . . . . . . . 13
4.1.11. "crit" (Critical) Header Parameter . . . . . . . . . . 13
4.2. Public Header Parameter Names . . . . . . . . . . . . . . 14
4.3. Private Header Parameter Names . . . . . . . . . . . . . . 14
5. Producing and Consuming JWSs . . . . . . . . . . . . . . . . . 14
5.1. Message Signature or MAC Computation . . . . . . . . . . . 14
5.2. Message Signature or MAC Validation . . . . . . . . . . . 15
5.3. String Comparison Rules . . . . . . . . . . . . . . . . . 16
6. Key Identification . . . . . . . . . . . . . . . . . . . . . . 17
7. Serializations . . . . . . . . . . . . . . . . . . . . . . . . 17
7.1. JWS Compact Serialization . . . . . . . . . . . . . . . . 18
7.2. JWS JSON Serialization . . . . . . . . . . . . . . . . . . 18
8. TLS Requirements . . . . . . . . . . . . . . . . . . . . . . . 19
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
9.1. JSON Web Signature and Encryption Header Parameters
Registry . . . . . . . . . . . . . . . . . . . . . . . . . 21
9.1.1. Registration Template . . . . . . . . . . . . . . . . 21
9.1.2. Initial Registry Contents . . . . . . . . . . . . . . 22
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9.2. Media Type Registration . . . . . . . . . . . . . . . . . 23
9.2.1. Registry Contents . . . . . . . . . . . . . . . . . . 23
10. Security Considerations . . . . . . . . . . . . . . . . . . . 24
10.1. Key Entropy . . . . . . . . . . . . . . . . . . . . . . . 25
10.2. Chosen Plaintext Attacks . . . . . . . . . . . . . . . . . 25
10.3. Timing Attacks . . . . . . . . . . . . . . . . . . . . . . 25
10.4. Differences between Digital Signatures and MACs . . . . . 25
10.5. SHA-1 Certificate Thumbprints . . . . . . . . . . . . . . 26
10.6. JSON Security Considerations . . . . . . . . . . . . . . . 26
10.7. Unicode Comparison Security Considerations . . . . . . . . 27
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 27
11.1. Normative References . . . . . . . . . . . . . . . . . . . 27
11.2. Informative References . . . . . . . . . . . . . . . . . . 29
Appendix A. JWS Examples . . . . . . . . . . . . . . . . . . . . 30
A.1. Example JWS using HMAC SHA-256 . . . . . . . . . . . . . . 30
A.1.1. Encoding . . . . . . . . . . . . . . . . . . . . . . . 30
A.1.2. Validating . . . . . . . . . . . . . . . . . . . . . . 32
A.2. Example JWS using RSASSA-PKCS-v1_5 SHA-256 . . . . . . . . 32
A.2.1. Encoding . . . . . . . . . . . . . . . . . . . . . . . 33
A.2.2. Validating . . . . . . . . . . . . . . . . . . . . . . 35
A.3. Example JWS using ECDSA P-256 SHA-256 . . . . . . . . . . 35
A.3.1. Encoding . . . . . . . . . . . . . . . . . . . . . . . 35
A.3.2. Validating . . . . . . . . . . . . . . . . . . . . . . 37
A.4. Example JWS using ECDSA P-521 SHA-512 . . . . . . . . . . 38
A.4.1. Encoding . . . . . . . . . . . . . . . . . . . . . . . 38
A.4.2. Validating . . . . . . . . . . . . . . . . . . . . . . 40
A.5. Example Plaintext JWS . . . . . . . . . . . . . . . . . . 40
A.6. Example JWS Using JWS JSON Serialization . . . . . . . . . 41
A.6.1. JWS Per-Signature Protected Headers . . . . . . . . . 41
A.6.2. JWS Per-Signature Unprotected Headers . . . . . . . . 42
A.6.3. Complete JOSE Header Values . . . . . . . . . . . . . 42
A.6.4. Complete JWS JSON Serialization Representation . . . . 42
Appendix B. "x5c" (X.509 Certificate Chain) Example . . . . . . . 43
Appendix C. Notes on implementing base64url encoding without
padding . . . . . . . . . . . . . . . . . . . . . . . 45
Appendix D. Notes on Key Selection . . . . . . . . . . . . . . . 46
Appendix E. Negative Test Case for "crit" Header Parameter . . . 47
Appendix F. Detached Content . . . . . . . . . . . . . . . . . . 48
Appendix G. Acknowledgements . . . . . . . . . . . . . . . . . . 48
Appendix H. Document History . . . . . . . . . . . . . . . . . . 49
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 58
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1. Introduction
JSON Web Signature (JWS) represents content secured with digital
signatures or Message Authentication Codes (MACs) using JavaScript
Object Notation (JSON) [RFC7159] based data structures. The JWS
cryptographic mechanisms provide integrity protection for an
arbitrary sequence of octets.
Two closely related serializations for JWS objects are defined. The
JWS Compact Serialization is a compact, URL-safe representation
intended for space constrained environments such as HTTP
Authorization headers and URI query parameters. The JWS JSON
Serialization represents JWS objects as JSON objects and enables
multiple signatures and/or MACs to be applied to the same content.
Both share the same cryptographic underpinnings.
Cryptographic algorithms and identifiers for use with this
specification are described in the separate JSON Web Algorithms (JWA)
[JWA] specification and an IANA registry defined by that
specification. Related encryption capabilities are described in the
separate JSON Web Encryption (JWE) [JWE] specification.
Names defined by this specification are short because a core goal is
for the resulting representations to be compact.
1.1. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in Key
words for use in RFCs to Indicate Requirement Levels [RFC2119]. If
these words are used without being spelled in uppercase then they are
to be interpreted with their normal natural language meanings.
BASE64URL(OCTETS) denotes the base64url encoding of OCTETS, per
Section 2.
UTF8(STRING) denotes the octets of the UTF-8 [RFC3629] representation
of STRING.
ASCII(STRING) denotes the octets of the ASCII [USASCII]
representation of STRING.
The concatenation of two values A and B is denoted as A || B.
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2. Terminology
These terms are defined by this specification:
JSON Web Signature (JWS)
A data structure representing a digitally signed or MACed message.
JOSE Header
JSON object containing the parameters describing the cryptographic
operations and parameters employed. The members of the JOSE
Header are Header Parameters.
JWS Payload
The sequence of octets to be secured -- a.k.a., the message. The
payload can contain an arbitrary sequence of octets.
JWS Signature
Digital signature or MAC over the JWS Protected Header and the JWS
Payload.
Header Parameter
A name/value pair that is member of the JOSE Header.
JWS Protected Header
JSON object that contains the Header Parameters that are integrity
protected by the JWS Signature digital signature or MAC operation.
For the JWS Compact Serialization, this comprises the entire JOSE
Header. For the JWS JSON Serialization, this is one component of
the JOSE Header.
JWS Unprotected Header
JSON object that contains the Header Parameters that are not
integrity protected. This can only be present when using the JWS
JSON Serialization.
Base64url Encoding
Base64 encoding using the URL- and filename-safe character set
defined in Section 5 of RFC 4648 [RFC4648], with all trailing '='
characters omitted (as permitted by Section 3.2) and without the
inclusion of any line breaks, white space, or other additional
characters. (See Appendix C for notes on implementing base64url
encoding without padding.)
JWS Signing Input
The input to the digital signature or MAC computation. Its value
is ASCII(BASE64URL(UTF8(JWS Protected Header)) || '.' ||
BASE64URL(JWS Payload)).
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JWS Compact Serialization
A representation of the JWS as a compact, URL-safe string.
JWS JSON Serialization
A representation of the JWS as a JSON object. Unlike the JWS
Compact Serialization, the JWS JSON Serialization enables multiple
digital signatures and/or MACs to be applied to the same content.
This representation is neither optimized for compactness nor URL-
safe.
Plaintext JWS
A JWS object that provides no integrity protection.
Collision-Resistant Name
A name in a namespace that enables names to be allocated in a
manner such that they are highly unlikely to collide with other
names. Examples of collision-resistant namespaces include: Domain
Names, Object Identifiers (OIDs) as defined in the ITU-T X.660 and
X.670 Recommendation series, and Universally Unique IDentifiers
(UUIDs) [RFC4122]. When using an administratively delegated
namespace, the definer of a name needs to take reasonable
precautions to ensure they are in control of the portion of the
namespace they use to define the name.
StringOrURI
A JSON string value, with the additional requirement that while
arbitrary string values MAY be used, any value containing a ":"
character MUST be a URI [RFC3986]. StringOrURI values are
compared as case-sensitive strings with no transformations or
canonicalizations applied.
These terms defined by the JSON Web Encryption (JWE) [JWE]
specification are incorporated into this specification: "JSON Web
Encryption (JWE)" and "JWE Compact Serialization".
3. JSON Web Signature (JWS) Overview
JWS represents digitally signed or MACed content using JSON data
structures and base64url encoding. A JWS represents these logical
values:
JOSE Header
JSON object containing the parameters describing the cryptographic
operations and parameters employed. For a JWS object, the JOSE
Header members are the union of the members of the JWS Protected
Header and the JWS Unprotected Header, as described below.
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JWS Payload
The sequence of octets to be secured -- a.k.a., the message. The
payload can contain an arbitrary sequence of octets.
JWS Signature
Digital signature or MAC over the JWS Protected Header and the JWS
Payload.
For a JWS object, the JOSE Header represents the combination of these
values:
JWS Protected Header
JSON object that contains the Header Parameters that are integrity
protected by the JWS Signature digital signature or MAC operation.
JWS Unprotected Header
JSON object that contains the Header Parameters that are not
integrity protected.
This document defines two serializations for JWS objects: a compact,
URL-safe serialization called the JWS Compact Serialization and a
JSON serialization called the JWS JSON Serialization. In both
serializations, the JWS Protected Header, JWS Payload, and JWS
Signature are base64url encoded for transmission, since JSON lacks a
way to directly represent octet sequences.
3.1. JWS Compact Serialization Overview
In the JWS Compact Serialization, no JWS Unprotected Header is used.
In this case, the JOSE Header and the JWS Protected Header are the
same.
In the JWS Compact Serialization, a JWS object is represented as the
combination of these three string values,
BASE64URL(UTF8(JWS Protected Header)),
BASE64URL(JWS Payload), and
BASE64URL(JWS Signature),
concatenated in that order, with the three strings being separated by
two period ('.') characters.
3.2. JWS JSON Serialization Overview
In the JWS JSON Serialization, one or both of the JWS Protected
Header and JWS Unprotected Header MUST be present. In this case, the
members of the JOSE Header are the combination of the members of the
JWS Protected Header and the JWS Unprotected Header values that are
present.
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In the JWS JSON Serialization, a JWS object is represented as the
combination of these four values,
BASE64URL(UTF8(JWS Protected Header)),
JWS Unprotected Header,
BASE64URL(JWS Payload), and
BASE64URL(JWS Signature),
with the three base64url encoding result strings and the JWS
Unprotected Header value being represented as members within a JSON
object. The inclusion of some of these values is OPTIONAL. The JWS
JSON Serialization can also represent multiple signature and/or MAC
values, rather than just one. See Section 7.2 for more information
about the JWS JSON Serialization.
3.3. Example JWS
This section provides an example of a JWS. Its computation is
described in more detail in Appendix A.1, including specifying the
exact octet sequences representing the JSON values used and the key
value used.
The following example JWS Protected Header declares that the encoded
object is a JSON Web Token (JWT) [JWT] and the JWS Protected Header
and the JWS Payload are secured using the HMAC SHA-256 [RFC2104, SHS]
algorithm:
{"typ":"JWT",
"alg":"HS256"}
Encoding this JWS Protected Header as BASE64URL(UTF8(JWS Protected
Header)) gives this value:
eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9
The UTF-8 representation of following JSON object is used as the JWS
Payload. (Note that the payload can be any content, and need not be
a representation of a JSON object.)
{"iss":"joe",
"exp":1300819380,
"http://example.com/is_root":true}
Encoding this JWS Payload as BASE64URL(JWS Payload) gives this value
(with line breaks for display purposes only):
eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFt
cGxlLmNvbS9pc19yb290Ijp0cnVlfQ
Computing the HMAC of the JWS Signing Input ASCII(BASE64URL(UTF8(JWS
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Protected Header)) || '.' || BASE64URL(JWS Payload)) with the HMAC
SHA-256 algorithm using the key specified in Appendix A.1 and
base64url encoding the result yields this BASE64URL(JWS Signature)
value:
dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk
Concatenating these values in the order Header.Payload.Signature with
period ('.') characters between the parts yields this complete JWS
representation using the JWS Compact Serialization (with line breaks
for display purposes only):
eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9
.
eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFt
cGxlLmNvbS9pc19yb290Ijp0cnVlfQ
.
dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk
See Appendix A for additional examples.
4. JOSE Header
For a JWS object, the members of the JSON object(s) representing the
JOSE Header describe the digital signature or MAC applied to the JWS
Protected Header and the JWS Payload and optionally additional
properties of the JWS. The Header Parameter names within the JOSE
Header MUST be unique; recipients MUST either reject JWSs with
duplicate Header Parameter names or use a JSON parser that returns
only the lexically last duplicate member name, as specified in
Section 15.12 (The JSON Object) of ECMAScript 5.1 [ECMAScript].
Implementations are required to understand the specific Header
Parameters defined by this specification that are designated as "MUST
be understood" and process them in the manner defined in this
specification. All other Header Parameters defined by this
specification that are not so designated MUST be ignored when not
understood. Unless listed as a critical Header Parameter, per
Section 4.1.11, all Header Parameters not defined by this
specification MUST be ignored when not understood.
There are three classes of Header Parameter names: Registered Header
Parameter names, Public Header Parameter names, and Private Header
Parameter names.
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4.1. Registered Header Parameter Names
The following Header Parameter names for use in JWS objects are
registered in the IANA JSON Web Signature and Encryption Header
Parameters registry defined in Section 9.1, with meanings as defined
below.
As indicated by the common registry, JWSs and JWEs share a common
Header Parameter space; when a parameter is used by both
specifications, its usage must be compatible between the
specifications.
4.1.1. "alg" (Algorithm) Header Parameter
The "alg" (algorithm) Header Parameter identifies the cryptographic
algorithm used to secure the JWS. The signature, MAC, or plaintext
value is not valid if the "alg" value does not represent a supported
algorithm, or if there is not a key for use with that algorithm
associated with the party that digitally signed or MACed the content.
"alg" values should either be registered in the IANA JSON Web
Signature and Encryption Algorithms registry defined in [JWA] or be a
value that contains a Collision-Resistant Name. The "alg" value is a
case-sensitive string containing a StringOrURI value. This Header
Parameter MUST be present and MUST be understood and processed by
implementations.
A list of defined "alg" values for this use can be found in the IANA
JSON Web Signature and Encryption Algorithms registry defined in
[JWA]; the initial contents of this registry are the values defined
in Section 3.1 of the JSON Web Algorithms (JWA) [JWA] specification.
4.1.2. "jku" (JWK Set URL) Header Parameter
The "jku" (JWK Set URL) Header Parameter is a URI [RFC3986] that
refers to a resource for a set of JSON-encoded public keys, one of
which corresponds to the key used to digitally sign the JWS. The
keys MUST be encoded as a JSON Web Key Set (JWK Set) [JWK]. The
protocol used to acquire the resource MUST provide integrity
protection; an HTTP GET request to retrieve the JWK Set MUST use TLS
[RFC2818, RFC5246]; the identity of the server MUST be validated, as
per Section 6 of RFC 6125 [RFC6125]. Use of this Header Parameter is
OPTIONAL.
4.1.3. "jwk" (JSON Web Key) Header Parameter
The "jwk" (JSON Web Key) Header Parameter is the public key that
corresponds to the key used to digitally sign the JWS. This key is
represented as a JSON Web Key [JWK]. Use of this Header Parameter is
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OPTIONAL.
4.1.4. "kid" (Key ID) Header Parameter
The "kid" (key ID) Header Parameter is a hint indicating which key
was used to secure the JWS. This parameter allows originators to
explicitly signal a change of key to recipients. The structure of
the "kid" value is unspecified. Its value MUST be a string. Use of
this Header Parameter is OPTIONAL.
When used with a JWK, the "kid" value is used to match a JWK "kid"
parameter value.
4.1.5. "x5u" (X.509 URL) Header Parameter
The "x5u" (X.509 URL) Header Parameter is a URI [RFC3986] that refers
to a resource for the X.509 public key certificate or certificate
chain [RFC5280] corresponding to the key used to digitally sign the
JWS. The identified resource MUST provide a representation of the
certificate or certificate chain that conforms to RFC 5280 [RFC5280]
in PEM encoded form [RFC1421]. The certificate containing the public
key corresponding to the key used to digitally sign the JWS MUST be
the first certificate. This MAY be followed by additional
certificates, with each subsequent certificate being the one used to
certify the previous one. The protocol used to acquire the resource
MUST provide integrity protection; an HTTP GET request to retrieve
the certificate MUST use TLS [RFC2818, RFC5246]; the identity of the
server MUST be validated, as per Section 6 of RFC 6125 [RFC6125].
Use of this Header Parameter is OPTIONAL.
4.1.6. "x5c" (X.509 Certificate Chain) Header Parameter
The "x5c" (X.509 Certificate Chain) Header Parameter contains the
X.509 public key certificate or certificate chain [RFC5280]
corresponding to the key used to digitally sign the JWS. The
certificate or certificate chain is represented as a JSON array of
certificate value strings. Each string in the array is a base64
encoded ([RFC4648] Section 4 -- not base64url encoded) DER
[ITU.X690.1994] PKIX certificate value. The certificate containing
the public key corresponding to the key used to digitally sign the
JWS MUST be the first certificate. This MAY be followed by
additional certificates, with each subsequent certificate being the
one used to certify the previous one. The recipient MUST validate
the certificate chain according to RFC 5280 [RFC5280] and reject the
signature if any validation failure occurs. Use of this Header
Parameter is OPTIONAL.
See Appendix B for an example "x5c" value.
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4.1.7. "x5t" (X.509 Certificate SHA-1 Thumbprint) Header Parameter
The "x5t" (X.509 Certificate SHA-1 Thumbprint) Header Parameter is a
base64url encoded SHA-1 thumbprint (a.k.a. digest) of the DER
encoding of the X.509 certificate [RFC5280] corresponding to the key
used to digitally sign the JWS. Use of this Header Parameter is
OPTIONAL.
4.1.8. "x5t#S256" (X.509 Certificate SHA-256 Thumbprint) Header
Parameter
The "x5t#S256" (X.509 Certificate SHA-256 Thumbprint) Header
Parameter is a base64url encoded SHA-256 thumbprint (a.k.a. digest)
of the DER encoding of the X.509 certificate [RFC5280] corresponding
to the key used to digitally sign the JWS. Use of this Header
Parameter is OPTIONAL.
4.1.9. "typ" (Type) Header Parameter
The "typ" (type) Header Parameter is used by JWS applications to
declare the MIME Media Type [IANA.MediaTypes] of this complete JWS
object. This is intended for use by the application when more than
one kind of object could be present in an application data structure
that can contain a JWS object; the application can use this value to
disambiguate among the different kinds of objects that might be
present. It will typically not be used by applications when the kind
of object is already known. This parameter is ignored by JWS
implementations; any processing of this parameter is performed by the
JWS application. Use of this Header Parameter is OPTIONAL.
Per RFC 2045 [RFC2045], all media type values, subtype values, and
parameter names are case-insensitive. However, parameter values are
case-sensitive unless otherwise specified for the specific parameter.
To keep messages compact in common situations, it is RECOMMENDED that
senders omit an "application/" prefix of a media type value in a
"typ" Header Parameter when no other '/' appears in the media type
value. A recipient using the media type value MUST treat it as if
"application/" were prepended to any "typ" value not containing a
'/'. For instance, a "typ" value of "example" SHOULD be used to
represent the "application/example" media type; whereas, the media
type "application/example;part="1/2"" cannot be shortened to
"example;part="1/2"".
The "typ" value "JOSE" can be used by applications to indicate that
this object is a JWS or JWE using the JWS Compact Serialization or
the JWE Compact Serialization. The "typ" value "JOSE+JSON" can be
used by applications to indicate that this object is a JWS or JWE
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using the JWS JSON Serialization or the JWE JSON Serialization.
Other type values can also be used by applications.
4.1.10. "cty" (Content Type) Header Parameter
The "cty" (content type) Header Parameter is used by JWS applications
to declare the MIME Media Type [IANA.MediaTypes] of the secured
content (the payload). This is intended for use by the application
when more than one kind of object could be present in the JWS
payload; the application can use this value to disambiguate among the
different kinds of objects that might be present. It will typically
not be used by applications when the kind of object is already known.
This parameter is ignored by JWS implementations; any processing of
this parameter is performed by the JWS application. Use of this
Header Parameter is OPTIONAL.
Per RFC 2045 [RFC2045], all media type values, subtype values, and
parameter names are case-insensitive. However, parameter values are
case-sensitive unless otherwise specified for the specific parameter.
To keep messages compact in common situations, it is RECOMMENDED that
senders omit an "application/" prefix of a media type value in a
"cty" Header Parameter when no other '/' appears in the media type
value. A recipient using the media type value MUST treat it as if
"application/" were prepended to any "cty" value not containing a
'/'. For instance, a "cty" value of "example" SHOULD be used to
represent the "application/example" media type; whereas, the media
type "application/example;part="1/2"" cannot be shortened to
"example;part="1/2"".
4.1.11. "crit" (Critical) Header Parameter
The "crit" (critical) Header Parameter indicates that extensions to
the initial RFC versions of [[ this specification ]] and [JWA] are
being used that MUST be understood and processed. Its value is an
array listing the Header Parameter names present in the JOSE Header
that use those extensions. If any of the listed extension Header
Parameters are not understood and supported by the receiver, it MUST
reject the JWS. Senders MUST NOT include Header Parameter names
defined by the initial RFC versions of [[ this specification ]] or
[JWA] for use with JWS, duplicate names, or names that do not occur
as Header Parameter names within the JOSE Header in the "crit" list.
Senders MUST NOT use the empty list "[]" as the "crit" value.
Recipients MAY reject the JWS if the critical list contains any
Header Parameter names defined by the initial RFC versions of [[ this
specification ]] or [JWA] for use with JWS, or any other constraints
on its use are violated. This Header Parameter MUST be integrity
protected, and therefore MUST occur only within the JWS Protected
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Header, when used. Use of this Header Parameter is OPTIONAL. This
Header Parameter MUST be understood and processed by implementations.
An example use, along with a hypothetical "exp" (expiration-time)
field is:
{"alg":"ES256",
"crit":["exp"],
"exp":1363284000
}
4.2. Public Header Parameter Names
Additional Header Parameter names can be defined by those using JWSs.
However, in order to prevent collisions, any new Header Parameter
name should either be registered in the IANA JSON Web Signature and
Encryption Header Parameters registry defined in Section 9.1 or be a
Public Name: a value that contains a Collision-Resistant Name. In
each case, the definer of the name or value needs to take reasonable
precautions to make sure they are in control of the part of the
namespace they use to define the Header Parameter name.
New Header Parameters should be introduced sparingly, as they can
result in non-interoperable JWSs.
4.3. Private Header Parameter Names
A producer and consumer of a JWS may agree to use Header Parameter
names that are Private Names: names that are not Registered Header
Parameter names Section 4.1 or Public Header Parameter names
Section 4.2. Unlike Public Header Parameter names, Private Header
Parameter names are subject to collision and should be used with
caution.
5. Producing and Consuming JWSs
5.1. Message Signature or MAC Computation
To create a JWS, one MUST perform these steps. The order of the
steps is not significant in cases where there are no dependencies
between the inputs and outputs of the steps.
1. Create the content to be used as the JWS Payload.
2. Compute the encoded payload value BASE64URL(JWS Payload).
3. Create the JSON object(s) containing the desired set of Header
Parameters, which together comprise the JOSE Header: the JWS
Protected Header, and if the JWS JSON Serialization is being
used, the JWS Unprotected Header.
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4. Compute the encoded header value BASE64URL(UTF8(JWS Protected
Header)). If the JWS Protected Header is not present (which can
only happen when using the JWS JSON Serialization and no
"protected" member is present), let this value be the empty
string.
5. Compute the JWS Signature in the manner defined for the
particular algorithm being used over the JWS Signing Input
ASCII(BASE64URL(UTF8(JWS Protected Header)) || '.' ||
BASE64URL(JWS Payload)). The "alg" (algorithm) Header Parameter
MUST be present in the JOSE Header, with the algorithm value
accurately representing the algorithm used to construct the JWS
Signature.
6. Compute the encoded signature value BASE64URL(JWS Signature).
7. These three encoded values are used in both the JWS Compact
Serialization and the JWS JSON Serialization representations.
8. If the JWS JSON Serialization is being used, repeat this process
(steps 3-7) for each digital signature or MAC operation being
performed.
9. Create the desired serialized output. The JWS Compact
Serialization of this result is BASE64URL(UTF8(JWS Protected
Header)) || '.' || BASE64URL(JWS Payload) || '.' || BASE64URL(JWS
Signature). The JWS JSON Serialization is described in
Section 7.2.
5.2. Message Signature or MAC Validation
When validating a JWS, the following steps MUST be taken. The order
of the steps is not significant in cases where there are no
dependencies between the inputs and outputs of the steps. If any of
the listed steps fails, then the signature or MAC cannot be
validated.
It is an application decision which signatures, MACs, or plaintext
values must successfully validate for the JWS to be accepted. In
some cases, all must successfully validate or the JWS will be
rejected. In other cases, only a specific signature, MAC, or
plaintext value needs to be successfully validated. However, in all
cases, at least one signature, MAC, or plaintext value MUST
successfully validate or the JWS MUST be rejected.
1. Parse the JWS representation to extract the serialized values
for the components of the JWS. When using the JWS Compact
Serialization, these components are the base64url encoded
representations of the JWS Protected Header, the JWS Payload,
and the JWS Signature, and when using the JWS JSON
Serialization, these components also include the unencoded JWS
Unprotected Header value. When using the JWS Compact
Serialization, the JWS Protected Header, the JWS Payload, and
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the JWS Signature are represented as base64url encoded values in
that order, separated by two period ('.') characters. The JWS
JSON Serialization is described in Section 7.2.
2. The encoded representation of the JWS Protected Header MUST be
successfully base64url decoded following the restriction that no
padding characters have been used.
3. The resulting octet sequence MUST be a UTF-8 encoded
representation of a completely valid JSON object conforming to
RFC 7159 [RFC7159], which is the JWS Protected Header.
4. If using the JWS Compact Serialization, let the JOSE Header be
the JWS Protected Header. Otherwise, when using the JWS JSON
Serialization, let the JOSE Header be the union of the members
of the corresponding JWS Protected Header and JWS Unprotected
Header, all of which must be completely valid JSON objects.
5. The resulting JOSE Header MUST NOT contain duplicate Header
Parameter names. When using the JWS JSON Serialization, this
restriction includes that the same Header Parameter name also
MUST NOT occur in distinct JSON object values that together
comprise the JOSE Header.
6. Verify that the implementation understands and can process all
fields that it is required to support, whether required by this
specification, by the algorithm being used, or by the "crit"
Header Parameter value, and that the values of those parameters
are also understood and supported.
7. The encoded representation of the JWS Payload MUST be
successfully base64url decoded following the restriction that no
padding characters have been used.
8. The encoded representation of the JWS Signature MUST be
successfully base64url decoded following the restriction that no
padding characters have been used.
9. The JWS Signature MUST be successfully validated against the JWS
Signing Input ASCII(BASE64URL(UTF8(JWS Protected Header)) || '.'
|| BASE64URL(JWS Payload)) in the manner defined for the
algorithm being used, which MUST be accurately represented by
the value of the "alg" (algorithm) Header Parameter, which MUST
be present.
10. If the JWS JSON Serialization is being used, repeat this process
(steps 4-9) for each digital signature or MAC value contained in
the representation.
5.3. String Comparison Rules
Processing a JWS inevitably requires comparing known strings to
members and values in a JSON object. For example, in checking what
the algorithm is, the Unicode string "alg" will be checked against
the member names in the JOSE Header to see if there is a matching
Header Parameter name. The same process is then used to determine if
the value of the "alg" Header Parameter represents a supported
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algorithm.
Since the only string comparison operations that are performed are
equality and inequality, the same rules can be used for comparing
both member names and member values against known strings. The JSON
rules for doing member name comparison are described in Section 8.3
of RFC 7159 [RFC7159].
Also, see the JSON security considerations in Section 10.6 and the
Unicode security considerations in Section 10.7.
6. Key Identification
It is necessary for the recipient of a JWS to be able to determine
the key that was employed for the digital signature or MAC operation.
The key employed can be identified using the Header Parameter methods
described in Section 4.1 or can be identified using methods that are
outside the scope of this specification. Specifically, the Header
Parameters "jku", "jwk", "kid", "x5u", "x5c", "x5t", and "x5t#S256"
can be used to identify the key used. These Header Parameters MUST
be integrity protected if the information that they convey is to be
utilized in a trust decision.
The sender SHOULD include sufficient information in the Header
Parameters to identify the key used, unless the application uses
another means or convention to determine the key used. Validation of
the signature or MAC fails when the algorithm used requires a key
(which is true of all algorithms except for "none") and the key used
cannot be determined.
The means of exchanging any shared symmetric keys used is outside the
scope of this specification.
Also, see Appendix D for notes on possible key selection algorithms.
7. Serializations
JWS objects use one of two serializations, the JWS Compact
Serialization or the JWS JSON Serialization. Applications using this
specification need to specify what serialization and serialization
features are used for that application. For instance, applications
might specify that only the JWS JSON Serialization is used, that only
JWS JSON Serialization support for a single signature or MAC value is
used, or that support for multiple signatures and/or MAC values is
used. JWS implementations only need to implement the features needed
for the applications they are designed to support.
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7.1. JWS Compact Serialization
The JWS Compact Serialization represents digitally signed or MACed
content as a compact URL-safe string. This string is
BASE64URL(UTF8(JWS Protected Header)) || '.' || BASE64URL(JWS
Payload) || '.' || BASE64URL(JWS Signature). Only one signature/MAC
is supported by the JWS Compact Serialization and it provides no
syntax to represent a JWS Unprotected Header value.
7.2. JWS JSON Serialization
The JWS JSON Serialization represents digitally signed or MACed
content as a JSON object. Content using the JWS JSON Serialization
can be secured with more than one digital signature and/or MAC
operation. This representation is neither optimized for compactness
nor URL-safe.
The following members are defined for use in top-level JSON objects
used for the JWS JSON Serialization:
payload
The "payload" member MUST be present and contain the value
BASE64URL(JWS Payload).
signatures
The "signatures" member value MUST be an array of JSON objects.
Each object represents a signature or MAC over the JWS Payload and
the JWS Protected Header.
The following members are defined for use in the JSON objects that
are elements of the "signatures" array:
protected
The "protected" member MUST be present and contain the value
BASE64URL(UTF8(JWS Protected Header)) when the JWS Protected
Header value is non-empty; otherwise, it MUST be absent. These
Header Parameter values are integrity protected.
header
The "header" member MUST be present and contain the value JWS
Unprotected Header when the JWS Unprotected Header value is non-
empty; otherwise, it MUST be absent. This value is represented as
an unencoded JSON object, rather than as a string. These Header
Parameter values are not integrity protected.
signature
The "signature" member MUST be present and contain the value
BASE64URL(JWS Signature).
At least one of the "protected" and "header" members MUST be present
for each signature/MAC computation so that an "alg" Header Parameter
value is conveyed.
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Additional members can be present in both the JSON objects defined
above; if not understood by implementations encountering them, they
MUST be ignored.
The Header Parameter values used when creating or validating
individual signature or MAC values are the union of the two sets of
Header Parameter values that may be present: (1) the JWS Protected
Header represented in the "protected" member of the signature/MAC's
array element, and (2) the JWS Unprotected Header in the "header"
member of the signature/MAC's array element. The union of these sets
of Header Parameters comprises the JOSE Header. The Header Parameter
names in the two locations MUST be disjoint.
Each JWS Signature value is computed using the parameters of the
corresponding JOSE Header value in the same manner as for the JWS
Compact Serialization. This has the desirable property that each JWS
Signature value represented in the "signatures" array is identical to
the value that would have been computed for the same parameter in the
JWS Compact Serialization, provided that the JWS Protected Header
value for that signature/MAC computation (which represents the
integrity-protected Header Parameter values) matches that used in the
JWS Compact Serialization.
In summary, the syntax of a JWS using the JWS JSON Serialization is
as follows:
{
"payload":"<payload contents>",
"signatures":[
{"protected":"<integrity-protected header 1 contents>",
"header":<non-integrity-protected header 1 contents>,
"signature":"<signature 1 contents>"},
...
{"protected":"<integrity-protected header N contents>",
"header":<non-integrity-protected header N contents>,
"signature":"<signature N contents>"}]
}
See Appendix A.6 for an example of computing a JWS using the JWS JSON
Serialization.
8. TLS Requirements
Implementations MUST support TLS. Which version(s) ought to be
implemented will vary over time, and depend on the widespread
deployment and known security vulnerabilities at the time of
implementation. At the time of this writing, TLS version 1.2
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[RFC5246] is the most recent version.
To protect against information disclosure and tampering,
confidentiality protection MUST be applied using TLS with a
ciphersuite that provides confidentiality and integrity protection.
See current publications by the IETF TLS working group, including RFC
6176 [RFC6176], for guidance on the ciphersuites currently considered
to be appropriate for use.
Whenever TLS is used, the identity of the service provider encoded in
the TLS server certificate MUST be verified using the procedures
described in Section 6 of RFC 6125 [RFC6125].
9. IANA Considerations
The following registration procedure is used for all the registries
established by this specification.
Values are registered on a Specification Required [RFC5226] basis
after a two-week review period on the [TBD]@ietf.org mailing list, on
the advice of one or more Designated Experts. However, to allow for
the allocation of values prior to publication, the Designated
Expert(s) may approve registration once they are satisfied that such
a specification will be published.
Registration requests must be sent to the [TBD]@ietf.org mailing list
for review and comment, with an appropriate subject (e.g., "Request
for access token type: example"). [[ Note to the RFC Editor: The name
of the mailing list should be determined in consultation with the
IESG and IANA. Suggested name: jose-reg-review. ]]
Within the review period, the Designated Expert(s) will either
approve or deny the registration request, communicating this decision
to the review list and IANA. Denials should include an explanation
and, if applicable, suggestions as to how to make the request
successful. Registration requests that are undetermined for a period
longer than 21 days can be brought to the IESG's attention (using the
iesg@iesg.org mailing list) for resolution.
Criteria that should be applied by the Designated Expert(s) includes
determining whether the proposed registration duplicates existing
functionality, determining whether it is likely to be of general
applicability or whether it is useful only for a single application,
and whether the registration makes sense.
IANA must only accept registry updates from the Designated Expert(s)
and should direct all requests for registration to the review mailing
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list.
It is suggested that multiple Designated Experts be appointed who are
able to represent the perspectives of different applications using
this specification, in order to enable broadly-informed review of
registration decisions. In cases where a registration decision could
be perceived as creating a conflict of interest for a particular
Expert, that Expert should defer to the judgment of the other
Expert(s).
9.1. JSON Web Signature and Encryption Header Parameters Registry
This specification establishes the IANA JSON Web Signature and
Encryption Header Parameters registry for Header Parameter names.
The registry records the Header Parameter name and a reference to the
specification that defines it. The same Header Parameter name can be
registered multiple times, provided that the parameter usage is
compatible between the specifications. Different registrations of
the same Header Parameter name will typically use different Header
Parameter Usage Location(s) values.
9.1.1. Registration Template
Header Parameter Name:
The name requested (e.g., "example"). Because a core goal of this
specification is for the resulting representations to be compact,
it is RECOMMENDED that the name be short -- not to exceed 8
characters without a compelling reason to do so. This name is
case-sensitive. Names may not match other registered names in a
case-insensitive manner unless the Designated Expert(s) state that
there is a compelling reason to allow an exception in this
particular case.
Header Parameter Description:
Brief description of the Header Parameter (e.g., "Example
description").
Header Parameter Usage Location(s):
The Header Parameter usage locations, which should be one or more
of the values "JWS" or "JWE".
Change Controller:
For Standards Track RFCs, state "IESG". For others, give the name
of the responsible party. Other details (e.g., postal address,
email address, home page URI) may also be included.
Specification Document(s):
Reference to the document(s) that specify the parameter,
preferably including URI(s) that can be used to retrieve copies of
the document(s). An indication of the relevant sections may also
be included but is not required.
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9.1.2. Initial Registry Contents
This specification registers the Header Parameter names defined in
Section 4.1 in this registry.
o Header Parameter Name: "alg"
o Header Parameter Description: Algorithm
o Header Parameter Usage Location(s): JWS
o Change Controller: IESG
o Specification Document(s): Section 4.1.1 of [[ this document ]]
o Header Parameter Name: "jku"
o Header Parameter Description: JWK Set URL
o Header Parameter Usage Location(s): JWS
o Change Controller: IESG
o Specification Document(s): Section 4.1.2 of [[ this document ]]
o Header Parameter Name: "jwk"
o Header Parameter Description: JSON Web Key
o Header Parameter Usage Location(s): JWS
o Change Controller: IESG
o Specification document(s): Section 4.1.3 of [[ this document ]]
o Header Parameter Name: "kid"
o Header Parameter Description: Key ID
o Header Parameter Usage Location(s): JWS
o Change Controller: IESG
o Specification Document(s): Section 4.1.4 of [[ this document ]]
o Header Parameter Name: "x5u"
o Header Parameter Description: X.509 URL
o Header Parameter Usage Location(s): JWS
o Change Controller: IESG
o Specification Document(s): Section 4.1.5 of [[ this document ]]
o Header Parameter Name: "x5c"
o Header Parameter Description: X.509 Certificate Chain
o Header Parameter Usage Location(s): JWS
o Change Controller: IESG
o Specification Document(s): Section 4.1.6 of [[ this document ]]
o Header Parameter Name: "x5t"
o Header Parameter Description: X.509 Certificate SHA-1 Thumbprint
o Header Parameter Usage Location(s): JWS
o Change Controller: IESG
o Specification Document(s): Section 4.1.7 of [[ this document ]]
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o Header Parameter Name: "x5t#S256"
o Header Parameter Description: X.509 Certificate SHA-256 Thumbprint
o Header Parameter Usage Location(s): JWS
o Change Controller: IESG
o Specification Document(s): Section 4.1.8 of [[ this document ]]
o Header Parameter Name: "typ"
o Header Parameter Description: Type
o Header Parameter Usage Location(s): JWS
o Change Controller: IESG
o Specification Document(s): Section 4.1.9 of [[ this document ]]
o Header Parameter Name: "cty"
o Header Parameter Description: Content Type
o Header Parameter Usage Location(s): JWS
o Change Controller: IESG
o Specification Document(s): Section 4.1.10 of [[ this document ]]
o Header Parameter Name: "crit"
o Header Parameter Description: Critical
o Header Parameter Usage Location(s): JWS
o Change Controller: IESG
o Specification Document(s): Section 4.1.11 of [[ this document ]]
9.2. Media Type Registration
9.2.1. Registry Contents
This specification registers the "application/jose" Media Type
[RFC2046] in the MIME Media Types registry [IANA.MediaTypes], which
can be used to indicate that the content is a JWS or JWE object using
the JWS Compact Serialization or the JWE Compact Serialization and
the "application/jose+json" Media Type in the MIME Media Types
registry, which can be used to indicate that the content is a JWS or
JWE object using the JWS JSON Serialization or the JWE JSON
Serialization.
o Type name: application
o Subtype name: jose
o Required parameters: n/a
o Optional parameters: n/a
o Encoding considerations: 8bit; application/jose values are encoded
as a series of base64url encoded values (some of which may be the
empty string) separated by period ('.') characters.
o Security considerations: See the Security Considerations section
of [[ this document ]]
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o Interoperability considerations: n/a
o Published specification: [[ this document ]]
o Applications that use this media type: OpenID Connect, Mozilla
Persona, Salesforce, Google, Android, Windows Azure, Xbox One, and
numerous others that use JWTs
o Additional information: Magic number(s): n/a, File extension(s):
n/a, Macintosh file type code(s): n/a
o Person & email address to contact for further information: Michael
B. Jones, mbj@microsoft.com
o Intended usage: COMMON
o Restrictions on usage: none
o Author: Michael B. Jones, mbj@microsoft.com
o Change Controller: IESG
o Type name: application
o Subtype name: jose+json
o Required parameters: n/a
o Optional parameters: n/a
o Encoding considerations: 8bit; application/jose+json values are
represented as a JSON Object; UTF-8 encoding SHOULD be employed
for the JSON object.
o Security considerations: See the Security Considerations section
of [[ this document ]]
o Interoperability considerations: n/a
o Published specification: [[ this document ]]
o Applications that use this media type: TBD
o Additional information: Magic number(s): n/a, File extension(s):
n/a, Macintosh file type code(s): n/a
o Person & email address to contact for further information: Michael
B. Jones, mbj@microsoft.com
o Intended usage: COMMON
o Restrictions on usage: none
o Author: Michael B. Jones, mbj@microsoft.com
o Change Controller: IESG
10. Security Considerations
All of the security issues that are pertinent to any cryptographic
application must be addressed by JWS/JWE/JWK agents. Among these
issues are protecting the user's asymmetric private and symmetric
secret keys, preventing various attacks, and helping avoid mistakes
such as inadvertently encrypting a message to the wrong recipient.
The entire list of security considerations is beyond the scope of
this document, but some significant considerations are listed here.
All the security considerations in XML DSIG 2.0
[W3C.NOTE-xmldsig-core2-20130411], also apply to this specification,
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other than those that are XML specific. Likewise, many of the best
practices documented in XML Signature Best Practices
[W3C.NOTE-xmldsig-bestpractices-20130411] also apply to this
specification, other than those that are XML specific.
10.1. Key Entropy
Keys are only as strong as the amount of entropy used to generate
them. A minimum of 128 bits of entropy should be used for all keys,
and depending upon the application context, more may be required. In
particular, it may be difficult to generate sufficiently random
values in some browsers and application environments.
10.2. Chosen Plaintext Attacks
Creators of JWSs should not allow third parties to insert arbitrary
content into the message without adding entropy not controlled by the
third party.
10.3. Timing Attacks
When cryptographic algorithms are implemented in such a way that
successful operations take a different amount of time than
unsuccessful operations, attackers may be able to use the time
difference to obtain information about the keys employed. Therefore,
such timing differences must be avoided.
10.4. Differences between Digital Signatures and MACs
While MACs and digital signatures can both be used for integrity
checking, there are some significant differences between the security
properties that each of them provides. These need to be taken into
consideration when designing protocols and selecting the algorithms
to be used in protocols.
Both signatures and MACs provide for integrity checking -- verifying
that the message has not been modified since the integrity value was
computed. However, MACs provide for origination identification only
under specific circumstances. It can normally be assumed that a
private key used for a signature is only in the hands of a single
entity (although perhaps a distributed entity, in the case of
replicated servers); however, a MAC key needs to be in the hands of
all the entities that use it for integrity computation and checking.
This means that origination can only be determined if a MAC key is
known only to two entities and the receiver knows that it did not
create the message. MAC validation cannot be used to prove
origination to a third party.
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10.5. SHA-1 Certificate Thumbprints
A SHA-1 hash is used when computing "x5t" (X.509 Certificate SHA-1
Thumbprint) values, for compatibility reasons. Should an effective
means of producing SHA-1 hash collisions be developed, and should an
attacker wish to interfere with the use of a known certificate on a
given system, this could be accomplished by creating another
certificate whose SHA-1 hash value is the same and adding it to the
certificate store used by the intended victim. A prerequisite to
this attack succeeding is the attacker having write access to the
intended victim's certificate store.
Alternatively, the "x5t#S256" (X.509 Certificate SHA-256 Thumbprint)
Header Parameter could be used instead of "x5t". However, at the
time of this writing, no development platform is known to support
SHA-256 certificate thumbprints.
10.6. JSON Security Considerations
Strict JSON [RFC7159] validation is a security requirement. If
malformed JSON is received, then the intent of the sender is
impossible to reliably discern. Ambiguous and potentially
exploitable situations could arise if the JSON parser used does not
reject malformed JSON syntax. In particular, any JSON inputs not
conforming to the JSON-text syntax defined in RFC 7159 input MUST be
rejected in their entirety.
Section 4 of the JSON Data Interchange Format specification [RFC7159]
states "The names within an object SHOULD be unique", whereas this
specification states that "Header Parameter names within this object
MUST be unique; recipients MUST either reject JWSs with duplicate
Header Parameter names or use a JSON parser that returns only the
lexically last duplicate member name, as specified in Section 15.12
(The JSON Object) of ECMAScript 5.1 [ECMAScript]". Thus, this
specification requires that the Section 4 "SHOULD" be treated as a
"MUST" by senders and that it be either treated as a "MUST" or in the
manner specified in ECMAScript 5.1 by receivers. Ambiguous and
potentially exploitable situations could arise if the JSON parser
used does not enforce the uniqueness of member names or returns an
unpredictable value for duplicate member names.
Some JSON parsers might not reject input that contains extra
significant characters after a valid input. For instance, the input
"{"tag":"value"}ABCD" contains a valid JSON-text object followed by
the extra characters "ABCD". Such input MUST be rejected in its
entirety.
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10.7. Unicode Comparison Security Considerations
Header Parameter names and algorithm names are Unicode strings. For
security reasons, the representations of these names must be compared
verbatim after performing any escape processing (as per Section 8.3
of RFC 7159 [RFC7159]). This means, for instance, that these JSON
strings must 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", "si\u0047").
JSON strings can contain characters outside the Unicode Basic
Multilingual Plane. For instance, the G clef character (U+1D11E) may
be represented in a JSON string as "\uD834\uDD1E". Ideally, JWS
implementations SHOULD ensure that characters outside the Basic
Multilingual Plane are preserved and compared correctly;
alternatively, if this is not possible due to these characters
exercising limitations present in the underlying JSON implementation,
then input containing them MUST be rejected.
11. References
11.1. Normative References
[ECMAScript]
Ecma International, "ECMAScript Language Specification,
5.1 Edition", ECMA 262, June 2011.
[IANA.MediaTypes]
Internet Assigned Numbers Authority (IANA), "MIME Media
Types", 2005.
[ITU.X690.1994]
International Telecommunications Union, "Information
Technology - ASN.1 encoding rules: Specification of Basic
Encoding Rules (BER), Canonical Encoding Rules (CER) and
Distinguished Encoding Rules (DER)", ITU-T Recommendation
X.690, 1994.
[JWA] Jones, M., "JSON Web Algorithms (JWA)",
draft-ietf-jose-json-web-algorithms (work in progress),
July 2014.
[JWK] Jones, M., "JSON Web Key (JWK)",
draft-ietf-jose-json-web-key (work in progress),
July 2014.
[RFC1421] Linn, J., "Privacy Enhancement for Internet Electronic
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Internet-Draft JSON Web Signature (JWS) July 2014
Mail: Part I: Message Encryption and Authentication
Procedures", RFC 1421, February 1993.
[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message
Bodies", RFC 2045, November 1996.
[RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types", RFC 2046,
November 1996.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, November 2003.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005.
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, October 2006.
[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.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, May 2008.
[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.
[