JSON Web Token (JWT)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
OAuth Working GroupAssertionClaimSecurity TokenJavaScript Object NotationJSONJSON Web TokenJWTJSON Object Signing and EncryptionJOSEJSON Web SignatureJWSJSON Web EncryptionJWEJSON Web KeyJWKJSON Web AlgorithmsJWA
JSON Web Token (JWT) is a compact, URL-safe means of representing claims to be
transferred between two parties. The claims in a JWT are
encoded as a JSON object that is
used as the payload of a JSON Web Signature (JWS) structure
or as the plaintext of a JSON Web Encryption (JWE) structure,
enabling the claims to be digitally signed or
integrity protected with a Message Authentication Code (MAC)
and/or encrypted.
JSON Web Token (JWT) is a compact claims representation format intended for
space constrained environments such as HTTP Authorization headers
and URI query parameters.
JWTs encode claims to be transmitted as a
JSON object that is
used as the payload of a JSON Web Signature (JWS) structure
or as the plaintext of a JSON Web Encryption (JWE) structure,
enabling the claims to be digitally signed or
integrity protected with a Message Authentication Code (MAC)
and/or encrypted.
JWTs are always represented using the JWS Compact Serialization
or the JWE Compact Serialization.
The suggested pronunciation of JWT is the same as the English
word "jot".
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" .
The interpretation should only be applied when the terms appear in all capital letters.
The terms
"JSON Web Signature (JWS)",
"Base64url Encoding",
"Header Parameter",
"JOSE Header",
"JWS Compact Serialization",
"JWS Payload",
"JWS Signature",
and "Unsecured JWS" are defined by
the JWS specification .
The terms
"JSON Web Encryption (JWE)",
"Content Encryption Key (CEK)",
"JWE Compact Serialization",
"JWE Encrypted Key",
and "JWE Initialization Vector"
are defined by
the JWE specification .
The terms
"Ciphertext",
"Digital Signature",
"Message Authentication Code (MAC)",
and "Plaintext" are defined by
the "Internet Security Glossary, Version 2".
These terms are defined by this specification:
A string representing a set of claims as a JSON object that is
encoded in a JWS or JWE,
enabling the claims to be digitally signed or MACed and/or encrypted.
A JSON object that
contains the claims conveyed by the JWT.
A piece of information asserted about a subject.
A claim is represented as a name/value pair
consisting of a Claim Name and a Claim Value.
The name portion of a claim representation.
A Claim Name is always a string.
The value portion of a claim representation.
A Claim Value can be any JSON value.
A JWT in which nested signing and/or encryption are employed.
In Nested JWTs, a JWT is used as the payload or plaintext value
of an enclosing JWS or JWE structure, respectively.
A JWT whose claims are not integrity protected or encrypted.
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.
A JSON numeric value representing the number of seconds
from 1970-01-01T00:00:00Z UTC until the specified UTC date/time,
ignoring leap seconds.
This is equivalent to the
IEEE Std 1003.1, 2013 Edition
definition "Seconds Since the Epoch",
in which each day is accounted for by exactly 86400 seconds,
other than that non-integer values can be represented.
See RFC 3339 for details
regarding date/times in general and UTC in particular.
JWTs represent a set of claims as a JSON object that is
encoded in a JWS and/or JWE structure.
This JSON object is the JWT Claims Set.
As per Section 4 of RFC 7159,
the JSON object consists of zero or more
name/value pairs (or members), where the names are strings and
the values are arbitrary JSON values.
These members are the claims represented by the JWT.
This JSON object MAY contain whitespace and/or line breaks
before or after any JSON values or structural characters,
in accordance with Section 2 of RFC 7159.
The member names within the JWT Claims Set are
referred to as Claim Names. The
corresponding values are referred to as Claim Values.
The contents of the JOSE Header describe the cryptographic
operations applied to the JWT Claims Set.
If the JOSE Header is for a JWS, the JWT is represented as a JWS
and the claims are digitally signed or MACed,
with the JWT Claims Set being the JWS Payload.
If the JOSE Header is for a JWE, the JWT is represented as a JWE
and the claims are encrypted,
with the JWT Claims Set being the plaintext encrypted by the JWE.
A JWT may be enclosed in another JWE or JWS structure
to create a Nested JWT,
enabling nested signing and encryption to be performed.
A JWT is represented as a sequence of URL-safe parts
separated by period ('.') characters.
Each part contains a base64url-encoded value.
The number of parts in the JWT is dependent upon
the representation of the resulting
JWS using the JWS Compact Serialization or
JWE using the JWE Compact Serialization.
The following example JOSE Header declares that the
encoded object is a JWT, and the JWT is
a JWS that is MACed using the HMAC SHA-256 algorithm:
To remove potential ambiguities in the representation of the JSON object above,
the octet sequence for the actual UTF-8 representation used in this example
for the JOSE Header above
is also included below.
(Note that ambiguities can arise due to
differing platform representations of line breaks (CRLF versus LF),
differing spacing at the beginning and ends of lines,
whether the last line has a terminating line break or not,
and other causes.
In the representation used in this example,
the first line has no leading or trailing spaces,
a CRLF line break (13, 10) occurs between the first and second lines,
the second line has one leading space (32) and no trailing spaces,
and the last line does not have a terminating line break.)
The octets representing the UTF-8 representation
of the JOSE Header in this example
(using JSON array notation) 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]
Base64url encoding the octets of the UTF-8 representation of
the JOSE Header yields this encoded JOSE Header value:
The following is an example of a JWT Claims Set:
The following octet sequence, which is the UTF-8 representation
used in this example for the JWT Claims Set 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]
Base64url encoding the JWS Payload yields this encoded JWS Payload
(with line breaks for display purposes only):
Computing the MAC of the encoded JOSE Header and encoded JWS Payload with
the HMAC SHA-256 algorithm and base64url encoding the
HMAC value in the
manner specified in
yields this encoded JWS Signature:
Concatenating these encoded parts in this order
with period ('.') characters between the
parts yields this complete JWT
(with line breaks for display purposes only):
This computation is illustrated in more detail in
Appendix A.1 of .
See for an example of
an encrypted JWT.
The JWT Claims Set represents a JSON object whose members
are the claims conveyed by the JWT.
The Claim Names within a JWT Claims Set MUST be unique;
JWT parsers MUST either reject JWTs with duplicate Claim 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 .
The set of claims that a
JWT must contain to be considered valid is context dependent
and is outside the scope of this specification.
Specific applications of JWTs will require implementations
to understand and process some claims in particular ways.
However, in the absence of such requirements, all claims
that are not understood by implementations MUST be ignored.
There are three classes of JWT Claim Names:
Registered Claim Names, Public Claim Names, and Private Claim Names.
The following Claim Names are registered
in the IANA
"JSON Web Token Claims" registry
established by
.
None of the claims
defined below are intended to be mandatory to use or implement in all cases, but
rather they provide a starting point for a set of useful,
interoperable claims.
Applications using JWTs should define which specific claims they use
and when they are required or optional.
All the names are short because a
core goal of JWTs is for the representation to be compact.
The iss (issuer) claim
identifies the principal that issued the JWT. The
processing of this claim is generally application
specific.
The iss value is a case-sensitive string
containing a StringOrURI value.
Use of this claim is OPTIONAL.
The sub (subject) claim
identifies the principal that is the subject of the JWT.
The claims in a JWT are normally statements about the subject.
The subject value MUST either be scoped to be locally unique
in the context of the issuer or be globally unique.
The processing of this claim is generally application specific.
The sub value is a case-sensitive string
containing a StringOrURI value.
Use of this claim is OPTIONAL.
The aud (audience) claim
identifies the recipients that the JWT is intended for.
Each principal intended to process the JWT MUST identify itself
with a value in the audience claim. If the principal
processing the claim does not identify itself with a
value in the aud claim when this claim is present,
then the JWT MUST be rejected.
In the general case,
the aud value is an array of
case-sensitive strings, each containing a StringOrURI value.
In the special case when the JWT has one audience,
the aud value MAY be a single
case-sensitive string containing a StringOrURI value.
The interpretation of audience values is generally application specific.
Use of this claim is OPTIONAL.
The exp (expiration time)
claim identifies the expiration time on or after which the
JWT MUST NOT be accepted for processing. The processing
of the exp claim requires that
the current date/time MUST be before the expiration
date/time listed in the exp
claim. Implementers MAY provide for some small leeway,
usually no more than a few minutes, to account for clock skew.
Its value MUST be a number containing a NumericDate value.
Use of this claim is OPTIONAL.
The nbf (not before) claim
identifies the time before which the JWT MUST NOT be
accepted for processing. The processing of the nbf claim requires that the current
date/time MUST be after or equal to the not-before
date/time listed in the nbf
claim. Implementers MAY provide for some small leeway,
usually no more than a few minutes, to account for clock skew.
Its value MUST be a number containing a NumericDate value.
Use of this claim is OPTIONAL.
The iat (issued at) claim
identifies the time at which the JWT was issued. This
claim can be used to determine the age of the JWT.
Its value MUST be a number containing a NumericDate value.
Use of this claim is OPTIONAL.
The jti (JWT ID) claim
provides a unique identifier for the JWT. The identifier
value MUST be assigned in a manner that ensures that there
is a negligible probability that the same value will be
accidentally assigned to a different data object;
if the application uses multiple issuers, collisions MUST be prevented
among values produced by different issuers as well.
The jti claim can be used to
prevent the JWT from being replayed.
The jti value is a case-sensitive string.
Use of this claim is OPTIONAL.
Claim Names can be defined at will by those using
JWTs. However, in order to prevent collisions, any new
Claim Name should either be registered in the IANA
"JSON Web Token Claims" registry
established by
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 Claim Name.
A producer and consumer of a JWT MAY agree to use Claim Names
that are Private Names: names that are
not Registered Claim Names ()
or Public Claim Names ().
Unlike Public Claim Names, Private Claim Names are subject to collision and
should be used with caution.
For a JWT object,
the members of the JSON object represented by the JOSE Header
describe the cryptographic operations applied to the JWT and
optionally, additional properties of the JWT.
Depending upon whether the JWT is a JWS or JWE,
the corresponding rules for the JOSE Header values apply.
This specification further specifies the use of the following
Header Parameters in both the cases where the JWT is a JWS and
where it is a JWE.
The typ (type) Header Parameter
defined by and
is used by JWT applications to declare the
media type
of this complete JWT.
This is intended for use by the JWT application when
values that are not JWTs could also be present in
an application data structure that can contain a JWT 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
it is already known that the object is a JWT.
This parameter is ignored by JWT implementations;
any processing of this parameter is performed by the JWT application.
If present, it is RECOMMENDED that its value be
JWT
to indicate that this object is a JWT.
While media type names are not case sensitive,
it is RECOMMENDED that JWT
always be spelled using uppercase characters
for compatibility with legacy implementations.
Use of this Header Parameter is OPTIONAL.
The cty (content type) Header Parameter
defined by and
is used by this specification
to convey structural information about the JWT.
In the normal case in which nested signing or encryption
operations are not employed, the use of this Header Parameter
is NOT RECOMMENDED.
In the case that nested signing or encryption is
employed, this Header Parameter MUST be present; in
this case, the value MUST be JWT, to indicate that
a Nested JWT is carried in this JWT.
While media type names are not case sensitive,
it is RECOMMENDED that JWT
always be spelled using uppercase characters
for compatibility with legacy implementations.
See for an example of a Nested JWT.
In some applications using encrypted JWTs, it is useful to
have an unencrypted representation of some claims.
This might be used, for instance, in application processing rules
to determine whether and how to process the JWT before
it is decrypted.
This specification allows claims present in the JWT Claims Set
to be replicated as Header Parameters in a JWT that is a JWE,
as needed by the application.
If such replicated claims are present, the application receiving them
SHOULD verify that their values are identical,
unless the application defines other specific processing rules for these claims.
It is the responsibility of the application to ensure that
only claims that are safe to be transmitted in an unencrypted manner
are replicated as Header Parameter values in the JWT.
of this specification registers the
iss (issuer),
sub (subject), and
aud (audience)
Header Parameter names for the purpose of
providing unencrypted replicas of these claims in encrypted JWTs
for applications that need them.
Other specifications MAY similarly register other names
that are registered Claim Names as Header Parameter names, as needed.
To support use cases in which the JWT content is secured by a
means other than a signature and/or encryption contained
within the JWT (such as a signature on a data structure
containing the JWT), JWTs MAY also be created without a
signature or encryption. An Unsecured JWT is a JWS using the
alg Header Parameter value
none and
with the empty string for its JWS Signature value,
as defined in the JWA specification ;
it is an Unsecured JWS with the JWT Claims Set as its JWS Payload.
The following example JOSE Header declares that the
encoded object is an Unsecured JWT:
Base64url encoding the octets of the UTF-8 representation of
the JOSE Header yields this encoded JOSE Header value:
The following is an example of a JWT Claims Set:
Base64url encoding the octets of the UTF-8 representation of
the JWT Claims Set yields this encoded JWS Payload
(with line breaks for display purposes only):
The encoded JWS Signature is the empty string.
Concatenating these encoded parts in this order
with period ('.') characters between the
parts yields this complete JWT
(with line breaks for display purposes only):
To create a JWT, the following steps are performed.
The order of the steps is not significant in cases where
there are no dependencies between the inputs and outputs of the steps.
Create a JWT Claims Set containing the desired claims.
Note that whitespace is explicitly allowed in the
representation and no canonicalization need be performed before
encoding.
Let the Message be the octets of the UTF-8 representation
of the JWT Claims Set.
Create a JOSE Header containing the desired set of Header Parameters.
The JWT
MUST conform to either the or specification.
Note that whitespace
is explicitly allowed in the representation and no
canonicalization need be performed before encoding.
Depending upon whether the JWT is a JWS or JWE,
there are two cases:
If the JWT is a JWS, create a JWS using
the Message as the JWS Payload;
all steps specified in
for creating a JWS MUST be followed.
Else, if the JWT is a JWE, create a JWE using
the Message as the plaintext for the JWE;
all steps specified in
for creating a JWE MUST be followed.
If a nested signing or encryption operation will be
performed, let the Message be the JWS or JWE, and
return to Step 3, using a cty (content type)
value of JWT
in the new JOSE Header created in that step.
Otherwise, let the resulting JWT be the JWS or JWE.
When validating a JWT, the following steps are performed.
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 fail, then the JWT MUST be rejected
-- that is, treated by the application as an invalid input.
Verify that the JWT contains at least one period ('.') character.
Let the Encoded JOSE Header be the portion of the JWT
before the first period ('.') character.
Base64url decode the Encoded JOSE Header
following the restriction that no line breaks, whitespace, or other additional characters have been used.
Verify that the resulting octet sequence
is a UTF-8-encoded representation of
a completely valid JSON object
conforming to RFC 7159;
let the JOSE Header be this JSON object.
Verify that the resulting JOSE Header includes only
parameters and values whose syntax and semantics are both
understood and supported
or that are specified as being ignored when not understood.
Determine whether the JWT is a JWS or a JWE
using any of the methods described in
Section 9 of .
Depending upon whether the JWT is a JWS or JWE,
there are two cases:
If the JWT is a JWS, follow the steps specified in
for validating a JWS.
Let the Message be the result of base64url decoding
the JWS Payload.
Else, if the JWT is a JWE, follow the steps specified in
for validating a JWE.
Let the Message be the resulting plaintext.
If the JOSE Header contains a cty (content type)
value of JWT,
then the Message is a JWT that was the subject of
nested signing or encryption operations. In
this case, return to Step 1, using the Message as the JWT.
Otherwise, base64url decode the Message
following the restriction that no line breaks, whitespace, or other additional characters have been used.
Verify that the resulting octet sequence
is a UTF-8-encoded representation of
a completely valid JSON object
conforming to RFC 7159;
let the JWT Claims Set be this JSON object.
Finally, note that it is an application decision which algorithms
may be used in a given context.
Even if a JWT can be successfully validated,
unless the algorithms used in the JWT are acceptable
to the application, it SHOULD reject the JWT.
Processing a JWT inevitably requires comparing known strings
to members and values in JSON objects. For example, in checking what the
algorithm is, the Unicode string encoding
alg will be
checked against the member names in the JOSE Header
to see if there is a matching Header Parameter name.
The JSON rules for doing member name comparison are described in
Section 8.3 of RFC 7159.
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.
These comparison rules MUST be used for all JSON string comparisons
except in cases where the definition of the member explicitly calls out that
a different comparison rule is to be used for that member value.
In this specification, only the typ and
cty member values do not use these comparison rules.
Some applications may include case-insensitive information in
a case-sensitive value, such as including a DNS name as part of
the iss (issuer) claim value.
In those cases, the application may need to define a convention
for the canonical case to use for representing the case-insensitive portions,
such as lowercasing them, if more than one party might need to
produce the same value so that they can be compared.
(However, if all other parties consume whatever value the producing party
emitted verbatim without attempting to compare it to an independently produced
value, then the case used by the producer will not matter.)
This section defines which algorithms and features of this specification
are mandatory to implement.
Applications using this specification can impose additional requirements
upon implementations that they use.
For instance, one application might require support for encrypted JWTs and Nested JWTs,
while another might require support for signing JWTs with the
Elliptic Curve Digital Signature Algorithm (ECDSA) using the P-256 curve and the SHA-256 hash algorithm
(ES256).
Of the signature and MAC algorithms specified in
JSON Web Algorithms , only
HMAC SHA-256
(HS256) and
none
MUST be implemented by conforming JWT implementations.
It is RECOMMENDED that implementations also support
RSASSA-PKCS1-v1_5 with the SHA-256 hash algorithm
(RS256) and
ECDSA using the P-256 curve and the SHA-256 hash algorithm
(ES256).
Support for other algorithms and key sizes is OPTIONAL.
Support for encrypted JWTs is OPTIONAL.
If an implementation provides encryption capabilities,
of the encryption algorithms specified in
, only
RSAES-PKCS1-v1_5 with 2048-bit keys
(RSA1_5),
AES Key Wrap with 128- and 256-bit keys
(A128KW and A256KW), and
the composite authenticated encryption algorithm using AES-CBC and HMAC SHA-2
(A128CBC-HS256 and A256CBC-HS512)
MUST be implemented by conforming implementations.
It is RECOMMENDED that implementations also support using
Elliptic Curve Diffie-Hellman Ephemeral Static (ECDH-ES)
to agree upon a key used to wrap the Content Encryption Key
(ECDH-ES+A128KW and ECDH-ES+A256KW)
and
AES in Galois/Counter Mode (GCM) with 128- and 256-bit keys
(A128GCM and A256GCM).
Support for other algorithms and key sizes is OPTIONAL.
Support for Nested JWTs is OPTIONAL.
This specification registers the URN
urn:ietf:params:oauth:token&nbhy;type:jwt
for use by applications that declare content types using URIs
(rather than, for instance, media types)
to indicate that the content referred to is a JWT.
This section establishes the
IANA "JSON Web Token Claims" registry
for JWT Claim Names.
The registry records the Claim Name
and a reference to the specification that defines it.
This section registers the Claim Names
defined in .
Values are registered on a Specification Required
basis after a three-week review period on the jwt-reg-review@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 Experts may approve
registration once they are satisfied that such a specification will be published.
Registration requests sent to the mailing list for review should use
an appropriate subject (e.g., "Request to register claim: example").
Within the review period, the Designated Experts 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@ietf.org mailing list) for resolution.
Criteria that should be applied by the Designated Experts includes
determining whether the proposed registration duplicates existing functionality,
whether it is likely to be of general applicability
or whether it is useful only for a single application,
and whether the registration description is clear.
IANA must only accept registry updates from the Designated Experts 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 Experts.
The name requested (e.g., "iss").
Because a core goal of this specification is for the resulting
representations to be compact, it is RECOMMENDED that the name be short
-- that is, 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 Experts state that there is a compelling reason
to allow an exception.
Brief description of the claim (e.g., "Issuer").
For Standards Track RFCs, list the "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 or documents that specify the parameter,
preferably including URIs that
can be used to retrieve copies of the documents.
An indication of the relevant
sections may also be included but is not required.
Claim Name: iss
Claim Description: Issuer
Change Controller: IESG
Specification Document(s): of RFC 7519
Claim Name: sub
Claim Description: Subject
Change Controller: IESG
Specification Document(s): of RFC 7519
Claim Name: aud
Claim Description: Audience
Change Controller: IESG
Specification Document(s): of RFC 7519
Claim Name: exp
Claim Description: Expiration Time
Change Controller: IESG
Specification Document(s): of RFC 7519
Claim Name: nbf
Claim Description: Not Before
Change Controller: IESG
Specification Document(s): of RFC 7519
Claim Name: iat
Claim Description: Issued At
Change Controller: IESG
Specification Document(s): of RFC 7519
Claim Name: jti
Claim Description: JWT ID
Change Controller: IESG
Specification Document(s): of RFC 7519
This section registers the value
token-type:jwt in the
IANA "OAuth URI" registry established by
"An IETF URN Sub-Namespace for OAuth",
which can be used to indicate that the content is a JWT.
URN: urn:ietf:params:oauth:token-type:jwtCommon Name: JSON Web Token (JWT) Token TypeChange Controller: IESGSpecification Document(s): RFC 7519
This section registers the application/jwt media type
in the "Media Types" registry
in the manner described in RFC 6838,
which can be used to indicate that the content is a JWT.
Type name: application
Subtype name: jwt
Required parameters: n/a
Optional parameters: n/a
Encoding considerations: 8bit;
JWT 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 RFC 7519
Interoperability considerations: n/a
Published specification: RFC 7519
Applications that use this media type:
OpenID Connect, Mozilla Persona, Salesforce, Google, Android,
Windows Azure, Amazon Web Services, and numerous others
Fragment identifier considerations: n/a
Additional information:Magic number(s): n/aFile extension(s): n/aMacintosh 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
Provisional registration? No
This section registers specific Claim Names defined in
in the IANA
"JSON Web Signature and Encryption Header Parameters" registry
established by
for use by claims replicated as Header Parameters in JWEs,
per .
Header Parameter Name: iss
Header Parameter Description: Issuer
Header Parameter Usage Location(s): JWE
Change Controller: IESG
Specification Document(s): of RFC 7519
Header Parameter Name: sub
Header Parameter Description: Subject
Header Parameter Usage Location(s): JWE
Change Controller: IESG
Specification Document(s): of RFC 7519
Header Parameter Name: aud
Header Parameter Description: Audience
Header Parameter Usage Location(s): JWE
Change Controller: IESG
Specification Document(s): of RFC 7519
All of the security issues that are pertinent to any cryptographic application
must be addressed by JWT/JWS/JWE/JWK agents. Among these issues are protecting
the user's asymmetric private and symmetric secret keys and
employing countermeasures to various attacks.
All the security considerations in the JWS specification also
apply to JWT, as do the JWE security considerations when
encryption is employed.
In particular,
Sections 10.12 ("JSON Security Considerations") and
10.13 ("Unicode Comparison Security Considerations")
of
apply equally to the JWT Claims Set in the same manner that
they do to the JOSE Header.
The contents of a JWT cannot be relied upon in a trust decision
unless its contents have been cryptographically secured and
bound to the context necessary for the trust decision.
In particular, the key(s) used to sign and/or encrypt the JWT
will typically need to verifiably be under the control
of the party identified as the issuer of the JWT.
While syntactically the signing and encryption operations for
Nested JWTs may be applied in any order,
if both signing and encryption are necessary,
normally producers should sign the message and then encrypt the
result (thus encrypting the signature). This prevents attacks
in which the signature is stripped, leaving just an encrypted
message, as well as providing privacy for the signer.
Furthermore, signatures over encrypted text are not considered
valid in many jurisdictions.
Note that potential concerns about security issues related to
the order of signing and encryption operations are already
addressed by the underlying JWS and JWE specifications;
in particular, because JWE only supports the use of
authenticated encryption algorithms, cryptographic concerns
about the potential need to sign after encryption that apply
in many contexts do not apply to this specification.
A JWT may contain privacy-sensitive information.
When this is the case, measures MUST be taken to prevent disclosure
of this information to unintended parties.
One way to achieve this is to use an encrypted JWT
and authenticate the recipient.
Another way is to ensure that JWTs containing unencrypted
privacy-sensitive information are only transmitted using
protocols utilizing encryption that support endpoint authentication, such as Transport Layer Security (TLS).
Omitting privacy-sensitive information from a JWT is the
simplest way of minimizing privacy issues.
ASCII format for Network InterchangeUniversity California Los Angeles (UCLA)The Unicode StandardThe Unicode ConsortiumJSON Web Signature (JWS)Microsoftmbj@microsoft.comhttp://self-issued.info/Ping Identityve7jtb@ve7jtb.comNomura Research Instituten-sakimura@nri.co.jpJSON Web Encryption (JWE)Microsoftmbj@microsoft.comhttp://self-issued.info/Cisco Systems, Inc.jhildebr@cisco.comJSON Web Algorithms (JWA)Microsoftmbj@microsoft.comhttp://self-issued.info/ECMAScript Language Specification, 5.1 EditionEcma InternationalMedia TypesIANAAssertions and Protocols for the OASIS Security Assertion Markup Language
(SAML) V2.0Internet2cantor.2@osu.eduNokiaJohn.Kemp@nokia.comRSA Securityrphilpott@rsasecurity.comSun Microsystemseve.maler@sun.comExtensible Markup Language (XML) 1.1 (Second Edition)Canonical XML Version 1.0The Open Group Base Specifications Issue 7IEEESimple Web Token (SWT)Magic SignaturesJSON Simple SignProtivity Government ServicesNomura Research InstituteCanvas ApplicationsFacebook
This section contains examples of JWTs.
For other example JWTs, see of this document and
Appendices A.1 - A.3 of .
This example encrypts the same claims as used in
to the recipient using RSAES-PKCS1-v1_5 and AES_128_CBC_HMAC_SHA_256.
The following example JOSE Header declares that:
The Content Encryption Key is encrypted to the recipient
using the RSAES-PKCS1-v1_5 algorithm to produce
the JWE Encrypted Key.
Authenticated encryption is performed on the plaintext
using the AES_128_CBC_HMAC_SHA_256 algorithm
to produce the JWE Ciphertext and the JWE Authentication Tag.
Other than using the octets of the UTF-8 representation of
the JWT Claims Set from
as the plaintext value, the computation of this JWT is
identical to the computation of the JWE in
Appendix A.2 of ,
including the keys used.
The final result in this example
(with line breaks for display purposes only) is:
This example shows how a JWT can be used as the payload
of a JWE or JWS to create a Nested JWT.
In this case, the JWT Claims Set is first signed, and then encrypted.
The inner signed JWT is identical to the example in
Appendix A.2 of .
Therefore, its computation is not repeated here.
This example then encrypts this inner JWT
to the recipient using RSAES&nbhy;PKCS1-v1_5 and AES_128_CBC_HMAC_SHA_256.
The following example JOSE Header declares that:
The Content Encryption Key is encrypted to the recipient
using the RSAES-PKCS1-v1_5 algorithm to produce
the JWE Encrypted Key.
Authenticated encryption is performed on the plaintext
using the AES_128_CBC_HMAC_SHA_256 algorithm
to produce the JWE Ciphertext and the JWE Authentication Tag.
The plaintext is itself a JWT.
Base64url encoding the octets of the UTF-8 representation of
the JOSE Header yields this encoded JOSE Header value:
The computation of this JWT is
identical to the computation of the JWE in
Appendix A.2 of ,
other than that different
JOSE Header,
plaintext,
JWE Initialization Vector, and
Content Encryption Key
values are used.
(The RSA key used is the same.)
The plaintext used is the octets of the ASCII representation of
the JWT at the end of Appendix A.2.1 of
(with all whitespace and line breaks removed),
which is a sequence of 458 octets.
The JWE Initialization Vector value used (using JSON array notation) is:
[82, 101, 100, 109, 111, 110, 100, 32, 87, 65, 32, 57, 56, 48, 53, 50]
This example uses the Content Encryption Key
represented by the base64url-encoded value below:
The final result for this Nested JWT
(with line breaks for display purposes only) is:
Security Assertion Markup Language (SAML) 2.0 provides
a standard for creating security tokens with greater expressivity
and more security options than supported by JWTs. However, the
cost of this flexibility and expressiveness is both size and complexity.
SAML's use of XML and
XML Digital Signature (DSIG) contributes to the size
of SAML Assertions; its use of XML and especially
XML Canonicalization
contributes to their complexity.
JWTs are intended to provide a simple security token format that is
small enough to fit into HTTP headers and query arguments in
URIs. It does this by supporting a much simpler token model
than SAML and using the JSON
object encoding syntax. It also supports securing tokens using
Message Authentication Codes (MACs) and digital
signatures using a smaller (and less flexible) format than XML
DSIG.
Therefore, while JWTs can do some of the things SAML Assertions
do, JWTs are not intended as a full replacement for SAML
Assertions, but rather as a token format to be used
when ease of implementation or compactness are considerations.
SAML Assertions are always statements made by an entity about a subject.
JWTs are often used in the same manner, with the entity making the
statements being represented by the iss (issuer) claim, and
the subject being represented by the sub (subject) claim.
However, with these claims being optional, other uses of the JWT format are also permitted.
Both JWTs and SWTs,
at their core, enable sets of claims to be communicated
between applications. For SWTs, both the claim names and
claim values are strings. For JWTs, while claim names are
strings, claim values can be any JSON type. Both token types
offer cryptographic protection of their content: SWTs with
HMAC SHA-256 and JWTs with a choice of algorithms, including
signature, MAC, and encryption algorithms.
The authors acknowledge that the design of JWTs was
intentionally influenced by the design and simplicity of SWTs and ideas for JSON
tokens that Dick Hardt discussed within the OpenID community.
Solutions for signing JSON content were previously explored by
Magic Signatures, JSON Simple Sign, and Canvas Applications, all of which
influenced this document.
This specification is the work of the OAuth 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,
Alissa Cooper,
Breno de Medeiros,
Stephen Farrell,
Yaron Y. Goland,
Dick Hardt,
Joe Hildebrand,
Jeff Hodges,
Edmund Jay,
Warren Kumari,
Ben Laurie,
Barry Leiba,
Ted Lemon,
James Manger,
Prateek Mishra,
Kathleen Moriarty,
Tony Nadalin,
Axel Nennker,
John Panzer,
Emmanuel Raviart,
David Recordon,
Eric Rescorla,
Jim Schaad,
Paul Tarjan,
Hannes Tschofenig,
Sean Turner,
and Tom Yu.
Hannes Tschofenig and Derek Atkins chaired the OAuth working group and
Sean Turner, Stephen Farrell, and Kathleen Moriarty served as Security Area Directors
during the creation of this specification.