JSON Web Signature (JWS)Microsoftmbj@microsoft.comhttp://self-issued.info/Ping Identityve7jtb@ve7jtb.comhttp://www.thread-safe.com/Nomura Research Instituten-sakimura@nri.co.jphttp://nat.sakimura.org/
Security
JOSE Working GroupRFCRequest for CommentsI-DInternet-DraftJavaScript Object NotationJSONJSON Object Signing and EncryptionJOSEJSON Web SignatureJWSJSON Web EncryptionJWEJSON Web KeyJWKJSON Web AlgorithmsJWA
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.
JSON Web Signature (JWS) represents
content secured with digital signatures or
Message Authentication Codes (MACs)
using JavaScript Object Notation (JSON)
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) specification
and an IANA registry defined by that specification.
Related encryption capabilities are described in the separate
JSON Web Encryption (JWE) specification.
Names defined by this specification are short because a core goal is
for the resulting representations to be compact.
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 .
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 .
UTF8(STRING) denotes the octets of the
UTF-8 representation of STRING.
ASCII(STRING) denotes the octets of the
ASCII representation of STRING.
The concatenation of two values A and B
is denoted as A || B.
A data structure representing a digitally signed or MACed message.
JSON object containing the parameters
describing the cryptographic operations and parameters employed.
The JWS Header members are the union of the members of
the JWS Protected Header
and the JWS Unprotected Header.
The members of the JWS Header are Header Parameters.
The sequence of octets to be secured -- a.k.a., the message.
The payload can contain an arbitrary sequence of octets.
Digital signature or MAC over
the JWS Protected Header and the JWS Payload.
A name/value pair that is member of the JWS Header.
JSON object that contains the JWS Header Parameters that are
integrity protected by
the JWS Signature digital signature or MAC operation.
For the JWS Compact Serialization, this comprises the entire JWS Header.
For the JWS JSON Serialization, this is one component of the JWS Header.
JSON object that contains the JWS Header Parameters that are not
integrity protected.
This can only be present when using the JWS JSON Serialization.
Base64 encoding using the URL- and filename-safe
character set defined in Section 5 of RFC 4648,
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 for notes on
implementing base64url encoding without padding.)
The input to the digital signature or MAC computation.
Its value is
ASCII(BASE64URL(UTF8(JWS Protected Header)) || '.' || BASE64URL(JWS Payload)).
A representation of the JWS as a compact, URL-safe string.
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.
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)
.
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.
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
.
StringOrURI values are compared as case-sensitive strings
with no transformations or canonicalizations applied.
JWS represents digitally signed or MACed content using JSON data
structures and base64url encoding.
A JWS represents these logical values:
JSON object containing the parameters
describing the cryptographic operations and parameters employed.
The JWS Header members are the union of the members of
the JWS Protected Header
and the JWS Unprotected Header, as described below.
The sequence of octets to be secured -- a.k.a., the message.
The payload can contain an arbitrary sequence of octets.
Digital signature or MAC over
the JWS Protected Header and the JWS Payload.
The JWS Header represents the combination of these values:
JSON object that contains the JWS Header Parameters that are
integrity protected by
the JWS Signature digital signature or MAC operation.
JSON object that contains the JWS 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.
In the JWS Compact Serialization, no JWS Unprotected Header is used.
In this case, the JWS 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), andBASE64URL(JWS Signature),
concatenated in that order,
with the three strings being separated by two period ('.') characters.
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 JWS Header are the combination of
the members of the JWS Protected Header and the JWS Unprotected Header
values that are present.
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), andBASE64URL(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 for more information
about the JWS JSON Serialization.
This section provides an example of a JWS.
Its computation is described in more detail in ,
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)
and the JWS Protected Header and the JWS Payload are
secured using the HMAC SHA-256 algorithm:
Encoding this JWS Protected Header as
BASE64URL(UTF8(JWS Protected Header)) gives this value:
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.)
Encoding this JWS Payload as
BASE64URL(JWS Payload) gives this value
(with line breaks for display purposes only):
Computing the HMAC of the JWS Signing Input
ASCII(BASE64URL(UTF8(JWS Protected Header)) || '.' || BASE64URL(JWS Payload))
with the HMAC SHA-256 algorithm
using the key specified in
and base64url encoding the result
yields this BASE64URL(JWS Signature) value:
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):
See for additional examples.
The members of the JSON object(s) representing the JWS 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 JWS 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 .
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 ,
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.
The following Header Parameter names are registered
in the IANA
JSON Web Signature and Encryption Header Parameters registry
defined in
,
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.
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
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
;
the initial contents of this registry are the values defined in
Section 3.1 of the
JSON Web Algorithms (JWA) specification.
The jku (JWK Set URL)
Header Parameter is a URI 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) .
The protocol used to acquire the resource MUST provide
integrity protection; an HTTP GET request to retrieve the
JWK Set MUST use TLS ;
the identity of the server MUST be validated, as per
Section 3.1 of HTTP Over TLS .
Use of this Header Parameter is OPTIONAL.
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 .
Use of this Header Parameter is OPTIONAL.
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.
The x5u (X.509 URL) Header Parameter
is a URI that refers to a resource for
the X.509 public key certificate or certificate chain
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 in PEM encoded form
.
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 ;
the identity of the server MUST be validated, as per
Section 3.1 of HTTP Over TLS .
Use of this Header Parameter is OPTIONAL.
The x5c (X.509 Certificate Chain)
Header Parameter contains the X.509 public key
certificate or certificate chain
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
( Section 4 -- not base64url encoded)
DER 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 and reject the signature if any
validation failure occurs.
Use of this Header Parameter is OPTIONAL.
See for an example
x5c value.
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
corresponding to the key
used to digitally sign the JWS.
Use of this Header Parameter is OPTIONAL.
If, in the future, certificate thumbprints need to be
computed using hash functions other than SHA-1, it is
suggested that additional related Header Parameters be
defined for that purpose. For example, it is suggested
that a new x5t#S256
(X.509 Certificate Thumbprint using SHA-256) Header Parameter
could be defined by registering it in the IANA
JSON Web Signature and Encryption Header Parameters registry
defined in
.
The typ (type) Header Parameter
is used to declare the
MIME Media Type
of this complete JWS object
in contexts where this is useful to the application.
This parameter has no effect upon the JWS processing.
Use of this Header Parameter is OPTIONAL.
Per , 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 using
the JWS JSON Serialization or the JWE JSON Serialization.
Other type values can also be used by applications.
The cty (content type) Header Parameter
is used to declare the
MIME Media Type
of the secured content (the payload)
in contexts where this is useful to the application.
This parameter has no effect upon the JWS processing.
Use of this Header Parameter is OPTIONAL.
Per , 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".
The crit (critical) Header Parameter
indicates that extensions to the initial RFC versions of
[[ this specification ]] and are being used
that MUST be understood and processed.
Its value is an array listing the Header Parameter names
present in the JWS 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 for use with JWS,
duplicate names, or
names that do not occur as Header Parameter names within the JWS 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 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 Header, when used.
Use of this Header Parameter is OPTIONAL.
This Header Parameter MUST be understood and processed by implementations.
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
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.
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
or Public Header Parameter names .
Unlike Public Header Parameter names,
Private Header Parameter names are subject to collision and
should be used with caution.
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.
Create the content to be used as the JWS Payload.
Compute the encoded payload value BASE64URL(JWS Payload).
Create the JSON object(s) containing the desired set of Header Parameters,
which together comprise the JWS Header:
the JWS Protected Header, and if the JWS JSON Serialization is being used,
the JWS Unprotected Header.
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.
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 JWS Header, with the algorithm value
accurately representing the algorithm used to construct
the JWS Signature.
Compute the encoded signature value BASE64URL(JWS Signature).
These three encoded values are used in both the
JWS Compact Serialization and the JWS JSON Serialization representations.
If the JWS JSON Serialization is being used, repeat this process
(steps 3-7)
for each digital signature or MAC operation being performed.
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 .
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.
Parse the JWS representation to extract the serialized values
for the components of the JWS --
when using the JWS Compact Serialization,
the base64url encoded representations of
the JWS Protected Header,
the JWS Payload, and
the JWS Signature,
and when using the JWS JSON Serialization,
also the unencoded JWS Unprotected Header value.
When using the JWS Compact Serialization,
the JWS Protected Header,
the JWS Payload, and
the JWS Signature
are represented as base64url encoded values in that order,
separated by two period ('.') characters.
The JWS JSON Serialization
is described in .
The encoded representation of the
JWS Protected Header
MUST be successfully base64url decoded following the
restriction that no padding characters have been used.
The resulting octet sequence
MUST be a UTF-8 encoded representation of
a completely valid JSON object
conforming to ,
which is the JWS Protected Header.
If using the JWS Compact Serialization, let the JWS Header be the
JWS Protected Header;
otherwise, when using the JWS JSON Serialization,
let the JWS 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.
The resulting JWS 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 JWS Header.
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.
The encoded representation of the
JWS Payload MUST be successfully base64url
decoded following the restriction that
no padding characters have been used.
The encoded representation of the
JWS Signature MUST be successfully base64url
decoded following the restriction that
no padding characters have been used.
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.
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.
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 JWS 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 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 .
Also, see the JSON security considerations in and
the Unicode security considerations in .
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 or can be identified
using methods that are outside the scope of this specification.
Specifically, the Header Parameters
jku,
jwk,
kid,
x5u,
x5c,
and x5t
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 for
notes on possible key selection algorithms.
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.
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.
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:
The payload member MUST be present and contain the value
BASE64URL(JWS Payload).
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:
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.
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.
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.
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 JWS Header.
The Header Parameter names in the two locations MUST be disjoint.
Each JWS Signature value is computed using the
parameters of the corresponding JWS 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.
See for an example
of computing a JWS using the JWS JSON Serialization.
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
is the most recent version, but has very limited actual
deployment, and might not be readily available in
implementation toolkits.
To protect against information disclosure and tampering,
confidentiality protection MUST be applied using TLS
with a ciphersuite that provides confidentiality and
integrity protection.
Whenever TLS is used, a TLS server certificate check
MUST be performed, per RFC 6125.
The following registration procedure is used for all the
registries established by this specification.
Values are registered with a Specification Required
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 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).
This specification establishes the
IANA JSON Web Signature and Encryption Header Parameters registry
for JWS and JWE 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.
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.
Brief description of the Header Parameter (e.g., "Example description").
The Header Parameter usage locations, which should be one or more of the values
JWS or
JWE.
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.
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.
This specification registers the Header Parameter names defined in
in this registry.
Header Parameter Name: alg
Header Parameter Description: Algorithm
Header Parameter Usage Location(s): JWS
Change Controller: IESG
Specification Document(s): of [[ this document ]]
Header Parameter Name: jku
Header Parameter Description: JWK Set URL
Header Parameter Usage Location(s): JWS
Change Controller: IESG
Specification Document(s): of [[ this document ]]
Header Parameter Name: jwk
Header Parameter Description: JSON Web Key
Header Parameter Usage Location(s): JWS
Change Controller: IESG
Specification document(s): of [[ this document ]]
Header Parameter Name: kid
Header Parameter Description: Key ID
Header Parameter Usage Location(s): JWS
Change Controller: IESG
Specification Document(s): of [[ this document ]]
Header Parameter Name: x5u
Header Parameter Description: X.509 URL
Header Parameter Usage Location(s): JWS
Change Controller: IESG
Specification Document(s): of [[ this document ]]
Header Parameter Name: x5c
Header Parameter Description: X.509 Certificate Chain
Header Parameter Usage Location(s): JWS
Change Controller: IESG
Specification Document(s): of [[ this document ]]
Header Parameter Name: x5t
Header Parameter Description: X.509 Certificate SHA-1 Thumbprint
Header Parameter Usage Location(s): JWS
Change Controller: IESG
Specification Document(s): of [[ this document ]]
Header Parameter Name: typ
Header Parameter Description: Type
Header Parameter Usage Location(s): JWS
Change Controller: IESG
Specification Document(s): of [[ this document ]]
Header Parameter Name: cty
Header Parameter Description: Content Type
Header Parameter Usage Location(s): JWS
Change Controller: IESG
Specification Document(s): of [[ this document ]]
Header Parameter Name: crit
Header Parameter Description: Critical
Header Parameter Usage Location(s): JWS
Change Controller: IESG
Specification Document(s): of [[ this document ]]
This specification registers the
application/jose
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 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.
Type name: application
Subtype name: jose
Required parameters: n/a
Optional parameters: n/a
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.
Security considerations: See the Security Considerations section of [[ this document ]]
Interoperability considerations: n/a
Published specification: [[ this document ]]
Applications that use this media type:
OpenID Connect, Mozilla Persona, Salesforce, Google, Android,
Windows Azure, Xbox One, and numerous others that use JWTs
Additional information:
Magic number(s): n/a,
File extension(s): n/a,
Macintosh file type code(s): n/a
Person & email address to contact for further information:
Michael B. Jones, mbj@microsoft.com
Intended usage: COMMON
Restrictions on usage: none
Author: Michael B. Jones, mbj@microsoft.com
Change Controller: IESG
Type name: application
Subtype name: jose+json
Required parameters: n/a
Optional parameters: n/a
Encoding considerations: 8bit;
application/jose+json values are represented as a JSON Object;
UTF-8 encoding SHOULD be employed for the JSON object.
Security considerations: See the Security Considerations section of [[ this document ]]
Interoperability considerations: n/a
Published specification: [[ this document ]]
Applications that use this media type:
TBD
Additional information:
Magic number(s): n/a,
File extension(s): n/a,
Macintosh file type code(s): n/a
Person & email address to contact for further information:
Michael B. Jones, mbj@microsoft.com
Intended usage: COMMON
Restrictions on usage: none
Author: Michael B. Jones, mbj@microsoft.com
Change Controller: IESG
All of the security issues faced by any cryptographic application
must be faced by a JWS/JWE/JWK agent. Among these issues are protecting
the user's private and symmetric keys, preventing various attacks, and helping the
user avoid mistakes such as inadvertently encrypting a message for
the wrong recipient. The entire list of security considerations is
beyond the scope of this document, but some significant concerns are
listed here.
All the security considerations in
XML DSIG 2.0,
also apply to this specification, other than those that are XML specific.
Likewise, many of the best practices documented in
XML Signature Best Practices
also apply to this specification,
other than those that are XML specific.
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.
Creators of JWSs should not allow third parties to insert
arbitrary content into the message without adding entropy
not controlled by the third party.
When utilizing TLS to retrieve information, the authority
providing the resource MUST be authenticated and the
information retrieved MUST be free from modification.
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.
A SHA-1 hash is used when computing
x5t (x.509 certificate 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.
If, in the future, certificate thumbprints need to be
computed using hash functions other than SHA-1, it is
suggested that additional related Header Parameters be
defined for that purpose. For example, it is suggested
that a new x5t#S256
(X.509 Certificate Thumbprint using SHA-256) Header Parameter
could be defined and used.
Strict JSON 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.
Section 4 of the JSON Data Interchange Format
specification 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 ".
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 object followed by
the extra characters ABCD.
Such input MUST be rejected in its entirety.
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 ).
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.
JSON Web Key (JWK)Microsoftmbj@microsoft.comhttp://self-issued.info/JSON Web Algorithms (JWA)Microsoftmbj@microsoft.comhttp://self-issued.info/Coded Character Set -- 7-bit American Standard Code for Information InterchangeAmerican National Standards InstituteECMAScript Language Specification, 5.1 EditionEcma InternationalMIME Media TypesInternet Assigned Numbers Authority (IANA)JSON Web Token (JWT)Microsoftmbj@microsoft.comhttp://self-issued.info/Ping Identityve7jtb@ve7jtb.comNomura Research Instituten-sakimura@nri.co.jpMagic SignaturesJSON Simple SignindependentNomura Research InstituteCanvas ApplicationsJSON Web Encryption (JWE)Microsoftmbj@microsoft.comhttp://self-issued.info/RTFM, Inc.ekr@rtfm.comCisco Systems, Inc.jhildebr@cisco.com
This section provides several examples of JWSs.
While the first three
examples all represent JSON Web Tokens (JWTs) , the payload can be any
octet sequence, as shown in .
The following example JWS Protected Header declares that the
data structure is a JSON Web Token (JWT)
and the JWS Signing Input is secured using
the HMAC SHA-256 algorithm.
The octets representing UTF8(JWS Protected Header) in this case are:
[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]
Encoding this JWS Protected Header as
BASE64URL(UTF8(JWS Protected Header)) gives this value:
The JWS Payload used in this example
is the octets of the UTF-8 representation of the JSON object below.
(Note that the payload can be any base64url
encoded octet sequence, and need not be a base64url encoded JSON
object.)
The following octet sequence, which is the UTF-8 representation
of the JSON object above, is the JWS Payload:
[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, 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, 111, 116, 34, 58, 116, 114, 117, 101, 125]
Encoding this JWS Protected Header as
BASE64URL(UTF8(JWS Protected Header)) gives this value
(with line breaks for display purposes only):
Combining these as
BASE64URL(UTF8(JWS Protected Header)) || '.' || BASE64URL(JWS Payload)
gives this string
(with line breaks for display purposes only):
The resulting JWS Signing Input value,
which is the ASCII representation of above string,
is the following octet sequence:
[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, 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, 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, 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, 106, 112, 48, 99, 110, 86, 108, 102, 81]
HMACs are generated using keys.
This example uses the symmetric key
represented in JSON Web Key format below
(with line breaks for display purposes only):
Running the HMAC SHA-256 algorithm on
the JWS Signing Input
with this key yields this JWS Signature octet sequence:
[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, 132, 141, 121]
Encoding this JWS Signature as
BASE64URL(JWS Signature) gives this value:
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):
Since the alg Header Parameter
is HS256, we validate the HMAC SHA-256
value contained in the JWS Signature.
To validate the HMAC value, we repeat the previous process
of using the correct key and
the JWS Signing Input
as input to the HMAC SHA-256 function
and then taking the output and determining if it matches
the JWS Signature. If it matches exactly,
the HMAC has been validated.
The JWS Protected Header in this example is different
from the previous example in two ways: First, because a
different algorithm is being used, the alg value is
different. Second, for illustration purposes only, the
optional typ parameter is not used.
(This difference is
not related to the algorithm employed.) The
JWS Protected Header used is:
The octets representing UTF8(JWS Protected Header) in this case are:
[123, 34, 97, 108, 103, 34, 58, 34, 82, 83, 50, 53, 54, 34, 125]
Encoding this JWS Protected Header as
BASE64URL(UTF8(JWS Protected Header)) gives this value:
The JWS Payload used in this example, which
follows, is the same as in the previous example. Since
the BASE64URL(JWS Payload) value will therefore be the same, its
computation is not repeated here.
Combining these as
BASE64URL(UTF8(JWS Protected Header)) || '.' || BASE64URL(JWS Payload)
gives this string
(with line breaks for display purposes only):
The resulting JWS Signing Input value,
which is the ASCII representation of above string,
is the following octet sequence:
[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, 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, 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, 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]
This example uses the RSA key
represented in JSON Web Key format below
(with line breaks for display purposes only):
The RSA private key is then passed to the RSA
signing function, which also takes the hash type, SHA-256,
and the JWS Signing Input
as inputs. The result of the digital signature is an octet sequence,
which represents a big endian integer. In this example, it
is:
[112, 46, 33, 137, 67, 232, 143, 209, 30, 181, 216, 45, 191, 120, 69, 243, 65, 6, 174, 27, 129, 255, 247, 115, 17, 22, 173, 209, 113, 125, 131, 101, 109, 66, 10, 253, 60, 150, 238, 221, 115, 162, 102, 62, 81, 102, 104, 123, 0, 11, 135, 34, 110, 1, 135, 237, 16, 115, 249, 69, 229, 130, 173, 252, 239, 22, 216, 90, 121, 142, 232, 198, 109, 219, 61, 184, 151, 91, 23, 208, 148, 2, 190, 237, 213, 217, 217, 112, 7, 16, 141, 178, 129, 96, 213, 248, 4, 12, 167, 68, 87, 98, 184, 31, 190, 127, 249, 217, 46, 10, 231, 111, 36, 242, 91, 51, 187, 230, 244, 74, 230, 30, 177, 4, 10, 203, 32, 4, 77, 62, 249, 18, 142, 212, 1, 48, 121, 91, 212, 189, 59, 65, 238, 202, 208, 102, 171, 101, 25, 129, 253, 228, 141, 247, 127, 55, 45, 195, 139, 159, 175, 221, 59, 239, 177, 139, 93, 163, 204, 60, 46, 176, 47, 158, 58, 65, 214, 18, 202, 173, 21, 145, 18, 115, 160, 95, 35, 185, 232, 56, 250, 175, 132, 157, 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, 99, 209, 108, 247, 202, 234, 86, 222, 64, 92, 178, 33, 90, 69, 178, 194, 85, 102, 181, 90, 193, 167, 72, 160, 112, 223, 200, 163, 42, 70, 149, 67, 208, 25, 238, 251, 71]
Encoding the signature as
BASE64URL(JWS Signature) produces this value
(with line breaks for display purposes only):
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):
Since the alg Header Parameter
is RS256, we
validate the RSASSA-PKCS-v1_5 SHA-256 digital signature contained in the JWS Signature.
Validating the JWS Signature is a little different
from the previous example.
We pass (n, e), JWS Signature, and
the JWS Signing Input
to an RSASSA-PKCS-v1_5 signature verifier that has
been configured to use the SHA-256 hash function.
The JWS Protected Header for this example differs from
the previous example because a different algorithm is
being used. The JWS Protected Header used is:
The octets representing UTF8(JWS Protected Header) in this case are:
[123, 34, 97, 108, 103, 34, 58, 34, 69, 83, 50, 53, 54, 34, 125]
Encoding this JWS Protected Header as
BASE64URL(UTF8(JWS Protected Header)) gives this value:
The JWS Payload used in this example, which
follows, is the same as in the previous examples. Since
the BASE64URL(JWS Payload) value will therefore be the same, its
computation is not repeated here.
Combining these as
BASE64URL(UTF8(JWS Protected Header)) || '.' || BASE64URL(JWS Payload)
gives this string
(with line breaks for display purposes only):
The resulting JWS Signing Input value,
which is the ASCII representation of above string,
is the following octet sequence:
[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, 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, 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, 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]
This example uses the elliptic curve key
represented in JSON Web Key format below:
The ECDSA private part d is then passed to an ECDSA
signing function, which also takes the curve type, P-256,
the hash type, SHA-256, and
the JWS Signing Input
as inputs. The result of the
digital signature is the EC point (R, S), where R and S are
unsigned integers. In this example, the R and S values,
given as octet sequences representing big endian integers are:
Result NameValueR
[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, 154, 195, 22, 158, 166, 101]
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, 143, 63, 127, 138, 131, 163, 84, 213]
The JWS Signature is the value R || S.
Encoding the signature as
BASE64URL(JWS Signature) produces this value
(with line breaks for display purposes only):
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):
Since the alg Header Parameter
is ES256, we
validate the ECDSA P-256 SHA-256 digital signature contained in
the JWS Signature.
Validating the JWS Signature is a little different
from the first example.
We need to split the 64 member octet sequence of the JWS Signature
into two 32 octet sequences, the first R and the second S. We
then pass (x, y), (R, S) and
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.
The JWS Protected Header for this example differs from
the previous example because different ECDSA curves
and hash functions are used. The JWS Protected Header used is:
The octets representing UTF8(JWS Protected Header) in this case are:
[123, 34, 97, 108, 103, 34, 58, 34, 69, 83, 53, 49, 50, 34, 125]
Encoding this JWS Protected Header as
BASE64URL(UTF8(JWS Protected Header)) gives this value:
The JWS Payload used in this example, is the ASCII string "Payload".
The representation of this string is the octet sequence:
[80, 97, 121, 108, 111, 97, 100]
Encoding this JWS Payload as
BASE64URL(JWS Payload) gives this value:
Combining these as
BASE64URL(UTF8(JWS Protected Header)) || '.' || BASE64URL(JWS Payload)
gives this string
(with line breaks for display purposes only):
The resulting JWS Signing Input value,
which is the ASCII representation of above string,
is the following octet sequence:
[101, 121, 74, 104, 98, 71, 99, 105, 79, 105, 74, 70, 85, 122, 85, 120, 77, 105, 74, 57, 46, 85, 71, 70, 53, 98, 71, 57, 104, 90, 65]
This example uses the elliptic curve key
represented in JSON Web Key format below
(with line breaks for display purposes only):
The ECDSA private part d is then passed to an ECDSA
signing function, which also takes the curve type, P-521,
the hash type, SHA-512, and
the JWS Signing Input
as inputs. The result of the
digital signature is the EC point (R, S), where R and S are
unsigned integers. In this example, the R and S values,
given as octet sequences representing big endian integers are:
Result NameValueR
[1, 220, 12, 129, 231, 171, 194, 209, 232, 135, 233, 117, 247, 105, 122, 210,
26, 125, 192, 1, 217, 21, 82, 91, 45, 240, 255, 83, 19, 34, 239, 71,
48, 157, 147, 152, 105, 18, 53, 108, 163, 214, 68, 231, 62, 153, 150, 106,
194, 164, 246, 72, 143, 138, 24, 50, 129, 223, 133, 206, 209, 172, 63, 237,
119, 109]
S
[0, 111, 6, 105, 44, 5, 41, 208, 128, 61, 152, 40, 92, 61,
152, 4, 150, 66, 60, 69, 247, 196, 170, 81, 193, 199, 78, 59, 194, 169,
16, 124, 9, 143, 42, 142, 131, 48, 206, 238, 34, 175, 83, 203, 220, 159,
3, 107, 155, 22, 27, 73, 111, 68, 68, 21, 238, 144, 229, 232, 148, 188,
222, 59, 242, 103]
The JWS Signature is the value R || S.
Encoding the signature as
BASE64URL(JWS Signature) produces this value
(with line breaks for display purposes only):
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):
Since the alg Header Parameter
is ES512, we
validate the ECDSA P-521 SHA-512 digital signature contained in
the JWS Signature.
Validating the JWS Signature is similar to the previous example.
We need to split the 132 member octet sequence of the JWS Signature
into two 66 octet sequences, the first R and the second S. We
then pass (x, y), (R, S) and
the JWS Signing Input
to an ECDSA signature verifier that
has been configured to use the P-521 curve with the
SHA-512 hash function.
The following example JWS Protected Header declares that the
encoded object is a Plaintext JWS:
Encoding this JWS Protected Header as
BASE64URL(UTF8(JWS Protected Header)) gives this value:
The JWS Payload used in this example, which
follows, is the same as in the previous examples. Since
the BASE64URL(JWS Payload) value will therefore be the same, its
computation is not repeated here.
The JWS Signature is the empty octet string
and BASE64URL(JWS Signature) is the empty string.
Concatenating these parts in the order
Header.Payload.Signature with period ('.') characters between the
parts yields this complete JWS (with line breaks for
display purposes only):
This section contains an example using the JWS JSON Serialization.
This example demonstrates the capability for
conveying multiple digital signatures and/or MACs for the
same payload.
The JWS Payload used in this example is the same as
that used in the examples in
and
(with line breaks for display purposes only):
Two digital signatures are used in this example:
the first using RSASSA-PKCS-v1_5 SHA-256 and
the second using ECDSA P-256 SHA-256.
For the first, the JWS Protected Header and key
are the same as in ,
resulting in the same JWS Signature value;
therefore, its computation is not repeated here.
For the second, the JWS Protected Header and key
are the same as in ,
resulting in the same JWS Signature value;
therefore, its computation is not repeated here.
The JWS Protected Header value used for the first signature is:
Encoding this JWS Protected Header as
BASE64URL(UTF8(JWS Protected Header)) gives this value:
The JWS Protected Header value used for the second signature is:
Encoding this JWS Protected Header as
BASE64URL(UTF8(JWS Protected Header)) gives this value:
Key ID values are supplied for both keys using per-signature
Header Parameters.
The two values used to represent these Key IDs are:
and
Combining the protected and unprotected header values
supplied, the JWS Header values used for the first and second
signatures respectively are:
and
The complete JSON Web Signature JSON Serialization
for these values is as follows
(with line breaks for display purposes only):
The JSON array below is an example of a certificate chain
that could be used as the value of an
x5c (X.509 Certificate Chain) Header Parameter,
per .
Note that since these strings contain base64 encoded (not base64url encoded)
values, they are allowed to contain white space and line breaks.
This appendix describes how to implement base64url encoding
and decoding functions without padding based upon standard
base64 encoding and decoding functions that do use padding.
To be concrete, example C# code implementing these functions
is shown below. Similar code could be used in other
languages.
As per the example code above, the number of '=' padding
characters that needs to be added to the end of a base64url
encoded string without padding to turn it into one with
padding is a deterministic function of the length of the
encoded string. Specifically,
if the length mod 4 is 0, no padding is added;
if the length mod 4 is 2, two '=' padding characters are added;
if the length mod 4 is 3, one '=' padding character is added;
if the length mod 4 is 1, the input is malformed.
An example correspondence between unencoded and encoded values
follows. The octet sequence below encodes into the string
below, which when decoded, reproduces the octet sequence.
This appendix describes a set of possible algorithms for selecting the key
to be used to validate the digital signature or MAC of a JWS object
or for selecting the key to be used to decrypt a JWE object.
This guidance describes a family of possible algorithms,
rather than a single algorithm,
because in different contexts, not all the sources of keys will be used,
they can be tried in different orders,
and sometimes not all the collected keys will be tried;
hence, different algorithms will be used in different application contexts.
The steps below are described for illustration purposes only;
specific applications can and are likely to use different algorithms
or perform some of the steps in different orders.
Specific applications will frequently have a much simpler method
of determining the keys to use, as there may be one or two key selection
methods that are profiled for the application's use.
This appendix supplements the normative information on key location
in .
These algorithms include the following steps.
Note that the steps can be performed in any order
and do not need to be treated as distinct.
For example, keys can be tried as soon as they are found,
rather than collecting all the keys before trying any.
Collect the set of potentially applicable keys.
Sources of keys may include:
Keys supplied by the application protocol being used.
Keys referenced by the jku (JWK Set URL)
Header Parameter.
The key provided by the jwk (JSON Web Key)
Header Parameter.
The key referenced by the x5u (X.509 URL)
Header Parameter.
The key provided by the
x5c (X.509 Certificate Chain)
Header Parameter.
Other applicable keys available to the application.
The order for collecting and trying keys from different key sources
is typically application dependent.
For example, frequently all keys from a one set of locations,
such as local caches,
will be tried before collecting and trying keys from other locations.
Filter the set of collected keys.
For instance, some applications will use only keys referenced by
kid (key ID) or
x5t (X.509 certificate SHA-1 thumbprint)
parameters.
If the application uses the
alg (algorithm),
use (public key use), or
key_ops (key operations) parameters,
keys with keys with inappropriate values of those parameters
would be excluded.
Additionally, keys might be filtered to include or exclude keys
with certain other member values in an application specific manner.
For some applications, no filtering will be applied.
Order the set of collected keys.
For instance, keys referenced by
kid (Key ID) or
x5t (X.509 Certificate SHA-1 Thumbprint)
parameters might be tried before keys with neither of these values.
Likewise, keys with certain member values
might be ordered before keys with other member values.
For some applications, no ordering will be applied.
Make trust decisions about the keys.
Signatures made with
keys not meeting the application's trust criteria would not be accepted.
Such criteria might include, but is not limited to
the source of the key,
whether the TLS certificate validates for keys retrieved from URLs,
whether a key in an X.509 certificate is backed by a valid certificate chain,
and other information known by the application.
Attempt signature or MAC validation for a JWS object
or decryption of a JWE object with
some or all of the collected and possibly filtered and/or ordered keys.
A limit on the number of keys to be tried might be applied.
This process will normally terminate following a successful validation
or decryption.
Note that it is reasonable for some applications to perform
signature or MAC validation prior to making a trust decision about a key,
since keys for which the validation fails need no trust decision.
Conforming implementations must reject input containing critical extensions
that are not understood or cannot be processed. The following JWS must
be rejected by all implementations, because it uses an extension
Header Parameter name http://example.invalid/UNDEFINED
that they do not understand.
Any other similar input, in which the use of the value
http://example.invalid/UNDEFINED is substituted for
any other Header Parameter name not understood by the implementation,
must also be rejected.
In some contexts, it is useful integrity protect content that
is not itself contained in a JWS object.
One way to do this is create a JWS object in the normal fashion using
a representation of the content as the payload,
but then delete the payload representation from the JWS,
and send this modified object to the recipient, rather than the JWS.
When using the JWS Compact Serialization, the deletion is accomplished
by replacing the second field (which contains BASE64URL(JWS Payload)) value
with the empty string;
when using the JWS JSON Serialization, the deletion is accomplished
by deleting the payload member.
This method assumes that the recipient can reconstruct
the exact payload used in the JWS.
To use the modified object, the recipient reconstructs the JWS
by re-inserting the payload representation into the modified object,
and uses the resulting JWS in the usual manner.
Note that this method needs no support from JWS libraries, as applications
can use this method by modifying the inputs and outputs of standard JWS libraries.
Solutions for signing JSON content were previously explored by
Magic Signatures, JSON Simple Sign, and Canvas Applications, all of which
influenced this draft.
Thanks to Axel Nennker for his early implementation
and feedback on the JWS and JWE specifications.
This specification is the work of the JOSE Working Group,
which includes dozens of active and dedicated participants.
In particular, the following individuals contributed ideas,
feedback, and wording that influenced this specification:
Dirk Balfanz,
Richard Barnes,
Brian Campbell,
Breno de Medeiros,
Dick Hardt,
Joe Hildebrand,
Jeff Hodges,
Edmund Jay,
Yaron Y. Goland,
Ben Laurie,
James Manger,
Matt Miller,
Tony Nadalin,
Axel Nennker,
John Panzer,
Emmanuel Raviart,
Eric Rescorla,
Jim Schaad,
Paul Tarjan,
Hannes Tschofenig,
and Sean Turner.
Jim Schaad and Karen O'Donoghue chaired the JOSE working group and
Sean Turner and Stephen Farrell served as Security area directors
during the creation of this specification.
[[ to be removed by the RFC Editor before publication as an RFC ]]
-23
Clarified that the base64url encoding includes no
line breaks, white space, or other additional characters.
-22
Corrected RFC 2119 terminology usage.
Replaced references to draft-ietf-json-rfc4627bis with RFC 7158.
-21
Applied review comments to the appendix "Notes on Key Selection",
addressing issue #93.
Changed some references from being normative to informative,
addressing issue #90.
Applied review comments to the JSON Serialization section,
addressing issue #121.
-20
Made terminology definitions more consistent,
addressing issue #165.
Restructured the JSON Serialization section to call out
the parameters used in hanging lists,
addressing issue #121.
Described key filtering and refined other aspects of
the text in the appendix "Notes on Key Selection",
addressing issue #93.
Replaced references to RFC 4627 with draft-ietf-json-rfc4627bis,
addressing issue #90.
-19
Added the appendix "Notes on Validation Key Selection",
addressing issue #93.
Reordered the key selection parameters.
-18
Updated the mandatory-to-implement (MTI) language to say that
applications using this specification need to specify what serialization
and serialization features are used for that application,
addressing issue #119.
Changes to address editorial and minor issues
#25, #89, #97, #110, #114, #115, #116, #117, #120, and #184.
Added and used Header Parameter Description registry field.
-17
Refined the typ and
cty definitions to always be
MIME Media Types, with the omission of "application/"
prefixes recommended for brevity,
addressing issue #50.
Updated the mandatory-to-implement (MTI) language to say
that general-purpose implementations must implement the
single signature/MAC value case for both serializations
whereas special-purpose implementations can implement
just one serialization if that meets the needs of
the use cases the implementation is designed for,
addressing issue #119.
Explicitly named all the logical components of a JWS
and defined the processing rules and serializations
in terms of those components,
addressing issues #60, #61, and #62.
Replaced verbose repetitive phases such as
"base64url encode the octets of the UTF-8 representation of X"
with mathematical notation such as "BASE64URL(UTF8(X))".
Terms used in multiple documents are now defined in
one place and incorporated by reference.
Some lightly used or obvious terms were also removed.
This addresses issue #58.
-16
Changes to address editorial and minor issues
#50, #98, #99, #102, #104, #106, #107, #111, and #112.
-15
Clarified that it is an application decision which
signatures, MACs, or plaintext values
must successfully validate for the JWS to be accepted,
addressing issue #35.
Corrected editorial error in ES512 example.
Changes to address editorial and minor issues
#34, #96, #100, #101, #104, #105, and #106.
-14
Stated that the signature parameter
is to be omitted in the JWS JSON Serialization
when its value would be empty
(which is only the case for a Plaintext JWS).
-13
Made all header parameter values be per-signature/MAC,
addressing issue #24.
-12
Clarified that the typ and
cty header parameters are used
in an application-specific manner
and have no effect upon the JWS processing.
Replaced the MIME types
application/jws+json and
application/jws with
application/jose+json and
application/jose.
Stated that recipients MUST either reject JWSs with
duplicate Header Parameter Names
or use a JSON parser that returns only
the lexically last duplicate member name.
Added a Serializations section with parallel treatment of the
JWS Compact Serialization
and the
JWS JSON Serialization
and also moved the former Implementation Considerations content there.
-11
Added Key Identification section.
For the JWS JSON Serialization, enable header parameter values
to be specified in any of three parameters:
the protected member that is
integrity protected and shared among all recipients,
the unprotected member that is
not integrity protected and shared among all recipients,
and the header member that is
not integrity protected and specific to a particular recipient.
(This does not affect the JWS Compact Serialization, in which all
header parameter values are in a single integrity protected JWE Header value.)
Removed suggested compact serialization for multiple
digital signatures and/or MACs.
Changed the MIME type name application/jws-js
to application/jws+json,
addressing issue #22.
Tightened the description of the
crit (critical) header parameter.
Added a negative test case for the
crit header parameter
-10
Added an appendix suggesting a possible compact serialization
for JWSs with multiple digital signatures and/or MACs.
-09
Added JWS JSON Serialization, as specified by
draft-jones-jose-jws-json-serialization-04.
Registered application/jws-js MIME type
and JWS-JS typ header parameter value.
Defined that the default action for header parameters that
are not understood is to ignore them unless specifically
designated as "MUST be understood" or included in the new
crit (critical) header parameter list.
This addressed issue #6.
Changed term "JWS Secured Input" to "JWS Signing Input".
Changed from using the term "byte" to "octet" when referring to 8 bit values.
Changed member name from recipients to
signatures in the JWS JSON Serialization.
Added complete values using the JWS Compact Serialization
for all examples.
-08
Applied editorial improvements suggested by
Jeff Hodges and Hannes Tschofenig.
Many of these simplified the terminology used.
Clarified statements of the form "This header parameter is OPTIONAL"
to "Use of this header parameter is OPTIONAL".
Added a Header Parameter Usage Location(s) field to the
IANA JSON Web Signature and Encryption Header Parameters registry.
Added seriesInfo information to Internet Draft references.
-07
Updated references.
-06
Changed x5c (X.509 Certificate Chain)
representation from being a single string to being an array of strings,
each containing a single base64 encoded DER certificate value,
representing elements of the certificate chain.
Applied changes made by the RFC Editor to RFC 6749's registry language
to this specification.
-05
Added statement that
"StringOrURI values are compared as case-sensitive strings
with no transformations or canonicalizations applied".
Indented artwork elements to better distinguish them from the body text.
-04
Completed JSON Security Considerations section, including
considerations about rejecting input with duplicate member names.
Completed security considerations on the use of a SHA-1 hash when computing
x5t (x.509 certificate thumbprint) values.
Refer to the registries as the primary sources of defined
values and then secondarily reference the sections
defining the initial contents of the registries.
Normatively reference
XML DSIG 2.0
for its security considerations.
Added this language to Registration Templates:
"This name is case sensitive. Names that match other registered names
in a case insensitive manner SHOULD NOT be accepted."
Reference draft-jones-jose-jws-json-serialization
instead of draft-jones-json-web-signature-json-serialization.
Described additional open issues.
Applied editorial suggestions.
-03
Added the cty (content type) header parameter
for declaring type information about the secured content,
as opposed to the typ (type) header parameter,
which declares type information about this object.
Added "Collision Resistant Namespace" to the terminology section.
Reference ITU.X690.1994 for DER encoding.
Added an example JWS using ECDSA P-521 SHA-512. This has particular
illustrative value because of the use of the 521 bit integers
in the key and signature values.
This is also an example in which the payload is not a base64url
encoded JSON object.
Added an example x5c value.
No longer say "the UTF-8 representation of the JWS Secured Input
(which is the same as the ASCII representation)". Just call it
"the ASCII representation of the JWS Secured Input".
Added Registration Template sections for defined registries.
Added Registry Contents sections to populate registry values.
Changed name of the JSON Web Signature and Encryption "typ" Values registry
to be the JSON Web Signature and Encryption Type Values registry, since
it is used for more than just values of the
typ parameter.
Moved registries
JSON Web Signature and Encryption Header Parameters and
JSON Web Signature and Encryption Type Values
to the JWS specification.
Numerous editorial improvements.
-02
Clarified that it is an error when a kid
value is included and no matching key is found.
Removed assumption that kid (key ID)
can only refer to an asymmetric key.
Clarified that JWSs with duplicate Header Parameter Names
MUST be rejected.
Clarified the relationship between
typ header parameter values
and MIME types.
Registered application/jws MIME type and "JWS" typ header parameter value.
Simplified JWK terminology to get replace the "JWK Key Object" and
"JWK Container Object" terms with simply "JSON Web Key (JWK)"
and "JSON Web Key Set (JWK Set)" and to eliminate potential
confusion between single keys and sets of keys.
As part of this change, the Header Parameter Name for a
public key value was changed from
jpk (JSON Public Key) to
jwk (JSON Web Key).
Added suggestion on defining additional header parameters
such as x5t#S256 in the future
for certificate thumbprints using hash algorithms other
than SHA-1.
Specify RFC 2818 server identity validation, rather than
RFC 6125 (paralleling the same decision in the OAuth specs).
Generalized language to refer to Message Authentication Codes (MACs)
rather than Hash-based Message Authentication Codes (HMACs)
unless in a context specific to HMAC algorithms.
Reformatted to give each header parameter its own section heading.
-01
Moved definition of Plaintext JWSs (using "alg":"none")
here from the JWT specification since this functionality is
likely to be useful in more contexts that just for JWTs.
Added jpk and x5c header parameters for including
JWK public keys and X.509 certificate chains directly in
the header.
Clarified that this specification is defining the JWS
Compact Serialization. Referenced the new JWS-JS spec,
which defines the JWS JSON Serialization.
Added text "New header parameters should be introduced
sparingly since an implementation that does not understand
a parameter MUST reject the JWS".
Clarified that the order of the creation and validation
steps is not significant in cases where there are no
dependencies between the inputs and outputs of the steps.
Changed "no canonicalization is performed" to "no
canonicalization need be performed".
Corrected the Magic Signatures reference.
Made other editorial improvements suggested by JOSE
working group participants.
-00
Created the initial IETF draft based upon
draft-jones-json-web-signature-04 with no normative
changes.
Changed terminology to no longer call both digital
signatures and HMACs "signatures".