jwt-0.7.2: JSON Web Token (JWT) decoding and encoding

Web.JWT

Description

This implementation of JWT is based on https://tools.ietf.org/html/rfc7519 but currently only implements the minimum required to work with the Atlassian Connect framework.

Known limitations:

• Only HMAC SHA-256 algorithm is currently a supported signature algorithm
• There is currently no verification of time related information (exp, nbf, iat).
• Registered claims are not validated

Synopsis

# Encoding & Decoding JWTs

## Decoding

There are three use cases supported by the set of decoding/verification functions:

1. Unsecured JWTs (http://tools.ietf.org/html/draft-ietf-oauth-json-web-token-30#section-6). This is supported by the decode function decode. As a client you don't care about signing or encrypting so you only get back a JWT UnverifiedJWT. I.e. the type makes it clear that no signature verification was attempted.
2. Signed JWTs you want to verify using a known secret. This is what decodeAndVerifySignature supports, given a secret and JSON it will return a JWT VerifiedJWT if the signature can be verified.
3. Signed JWTs that need to be verified using a secret that depends on information contained in the JWT. E.g. the secret depends on some claim, therefore the JWT needs to be decoded first and after retrieving the appropriate secret value, verified in a subsequent step. This is supported by using the verify function which given a JWT UnverifiedJWT and a secret will return a JWT VerifiedJWT iff the signature can be verified.

Decode a claims set without verifying the signature. This is useful if information from the claim set is required in order to verify the claim (e.g. the secret needs to be retrieved based on unverified information from the claims set).

>>> :{
 let
input = "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJzb21lIjoicGF5bG9hZCJ9.Joh1R2dYzkRvDkqv3sygm5YyK8Gi4ShZqbhK2gxcs2U" :: T.Text
mJwt = decode input
:}
Just (JOSEHeader {typ = Just "JWT", cty = Nothing, alg = Just HS256})


and

>>> :{
 let
input = "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJzb21lIjoicGF5bG9hZCJ9.Joh1R2dYzkRvDkqv3sygm5YyK8Gi4ShZqbhK2gxcs2U" :: T.Text
mJwt = decode input
in fmap claims mJwt
:}
Just (JWTClaimsSet {iss = Nothing, sub = Nothing, aud = Nothing, exp = Nothing, nbf = Nothing, iat = Nothing, jti = Nothing, unregisteredClaims = fromList [("some",String "payload")]})


Using a known secret and a decoded claims set verify that the signature is correct and return a verified JWT token as a result.

This will return a VerifiedJWT if and only if the signature can be verified using the given secret.

The separation between decode and verify is very useful if you are communicating with multiple different services with different secrets and it allows you to lookup the correct secret for the unverified JWT before trying to verify it. If this is not an isuse for you (there will only ever be one secret) then you should just use decodeAndVerifySignature.

>>> :{
 let
input = "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJzb21lIjoicGF5bG9hZCJ9.Joh1R2dYzkRvDkqv3sygm5YyK8Gi4ShZqbhK2gxcs2U" :: T.Text
mUnverifiedJwt = decode input
mVerifiedJwt = verify (secret "secret") =<< mUnverifiedJwt
in signature =<< mVerifiedJwt
:}
Just (Signature "Joh1R2dYzkRvDkqv3sygm5YyK8Gi4ShZqbhK2gxcs2U")


Decode a claims set and verify that the signature matches by using the supplied secret. The algorithm is based on the supplied header value.

This will return a VerifiedJWT if and only if the signature can be verified using the given secret.

>>> :{
 let
input = "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJzb21lIjoicGF5bG9hZCJ9.Joh1R2dYzkRvDkqv3sygm5YyK8Gi4ShZqbhK2gxcs2U" :: T.Text
mJwt = decodeAndVerifySignature (secret "secret") input
in signature =<< mJwt
:}
Just (Signature "Joh1R2dYzkRvDkqv3sygm5YyK8Gi4ShZqbhK2gxcs2U")


## Encoding

Encode a claims set using the given secret

 let
cs = def { -- def returns a default JWTClaimsSet
iss = stringOrURI Foo
, unregisteredClaims = Map.fromList [("http://example.com/is_root", (Bool True))]
}
key = secret "secret-key"
in encodeSigned HS256 key cs

"eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJodHRwOi8vZXhhbXBsZS5jb20vaXNfcm9vdCI6dHJ1ZSwiaXNzIjoiRm9vIn0.vHQHuG3ujbnBUmEp-fSUtYxk27rLiP2hrNhxpyWhb2E"

Encode a claims set without signing it

 let
cs = def { -- def returns a default JWTClaimsSet
iss = stringOrURI Foo
, iat = numericDate 1394700934
, unregisteredClaims = Map.fromList [("http://example.com/is_root", (Bool True))]
}
in encodeUnsigned cs

"eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpYXQiOjEzOTQ3MDA5MzQsImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlLCJpc3MiOiJGb28ifQ."

# Utility functions

## Common

Try to extract the value for the issue claim field iss from the web token in JSON form

Create a Secret using the given key. Consider using binarySecret instead if your key is not already a Data.Text.

Create a Secret using the given key.

## JWT structure

Extract the claims set from a JSON Web Token

Extract the header from a JSON Web Token

Extract the signature from a verified JSON Web Token

## JWT claims set

Convert the aud claim in a JWTClaimsSet into a [StringOrURI]

Deprecated: Use numericDate instead. intDate will be removed in 1.0

Convert the NominalDiffTime into an IntDate. Returns a Nothing if the argument is invalid (e.g. the NominalDiffTime must be convertible into a positive Integer representing the seconds since epoch).

Convert the NominalDiffTime into an NumericDate. Returns a Nothing if the argument is invalid (e.g. the NominalDiffTime must be convertible into a positive Integer representing the seconds since epoch).

Convert a Text into a StringOrURI. Returns a Nothing if the String cannot be converted (e.g. if the String contains a : but is *not* a valid URI).

Convert a StringOrURI into a Text. Returns the T.Text representing the String as-is or a Text representation of the URI otherwise.

Return the seconds since 1970-01-01T0:0:0Z UTC for the given IntDate

The typ (type) Header Parameter defined by [JWS] and [JWE] is used to declare the MIME Media Type [IANA.MediaTypes] of this complete JWT in contexts where this is useful to the application. This parameter has no effect upon the JWT processing.

The cty (content type) Header Parameter defined by [JWS] and [JWE] is used by this specification to convey structural information about the JWT.

The alg (algorithm) used for signing the JWT. The HS256 (HMAC using SHA-256) is the only required algorithm and the only one supported in this implementation in addition to "none" which means that no signature will be used.

# Types

JSON Web Token without signature verification

JSON Web Token that has been successfully verified

data Signature Source #

Instances

 Source # Methods Source # MethodsshowList :: [Signature] -> ShowS #

data Secret Source #

The secret used for calculating the message signature

Instances

 Source # Methods(==) :: Secret -> Secret -> Bool #(/=) :: Secret -> Secret -> Bool # Source # MethodsshowsPrec :: Int -> Secret -> ShowS #showList :: [Secret] -> ShowS #

data JWT r Source #

The JSON Web Token

Instances

 Show (JWT r) Source # MethodsshowsPrec :: Int -> JWT r -> ShowS #show :: JWT r -> String #showList :: [JWT r] -> ShowS #

type JSON = Text Source #

data Algorithm Source #

Constructors

 HS256 HMAC using SHA-256 hash algorithm

Instances

 Source # Methods Source # MethodsshowList :: [Algorithm] -> ShowS # Source # Methods Source # Methods

The JWT Claims Set represents a JSON object whose members are the claims conveyed by the JWT.

Constructors

 JWTClaimsSet Fieldsiss :: Maybe StringOrURIThe iss (issuer) claim identifies the principal that issued the JWT.sub :: Maybe StringOrURIThe sub (subject) claim identifies the principal that is the subject of the JWT.aud :: Maybe (Either StringOrURI [StringOrURI])The aud (audience) claim identifies the audiences that the JWT is intended for according to draft 18 of the JWT spec, the aud claim is option and may be present in singular or as a list.exp :: Maybe IntDateThe exp (expiration time) claim identifies the expiration time on or after which the JWT MUST NOT be accepted for processing. Its value MUST be a number containing an IntDate value.nbf :: Maybe IntDateThe nbf (not before) claim identifies the time before which the JWT MUST NOT be accepted for processing.iat :: Maybe IntDateThe iat (issued at) claim identifies the time at which the JWT was issued.jti :: Maybe StringOrURIThe jti (JWT ID) claim provides a unique identifier for the JWT.unregisteredClaims :: ClaimsMap

Instances

 Source # Methods Source # MethodsshowList :: [JWTClaimsSet] -> ShowS # Source # Methods Source # Methods Source # Methods

Deprecated: Use NumericDate instead. IntDate will be removed in 1.0

A JSON numeric value representing the number of seconds from 1970-01-01T0:0:0Z UTC until the specified UTC date/time.

A JSON numeric value representing the number of seconds from 1970-01-01T0:0:0Z UTC until the specified UTC date/time.

Instances

 Source # Methods Source # Methods Source # MethodsshowList :: [NumericDate] -> ShowS # Source # Methods Source # Methods

A JSON string value, with the additional requirement that while arbitrary string values MAY be used, any value containing a ":" character MUST be a URI [RFC3986]. StringOrURI values are compared as case-sensitive strings with no transformations or canonicalizations applied.

Instances

 Source # Methods Source # MethodsshowList :: [StringOrURI] -> ShowS # Source # Methods Source # Methods