Algorithm Management

Set and check algorithms and algorithm specific values. More...

Collaboration diagram for Algorithm Management:

Functions
int	jwt_set_alg (jwt_t *jwt, jwt_alg_t alg, const unsigned char *key, int len)
	Set an algorithm for a jwt_t object.
jwt_alg_t	jwt_get_alg (const jwt_t *jwt)
	Get the jwt_alg_t set for this JWT object.
const char *	jwt_alg_str (jwt_alg_t alg)
	Convert alg type to it's string representation.
jwt_alg_t	jwt_str_alg (const char *alg)
	Convert alg string to type.

Detailed Description

Set and check algorithms and algorithm specific values.

When working with functions that require a key, the underlying library takes care to scrub memory when the key is no longer used (e.g. when calling jwt_free() or when changing the algorithm, the old key, if it exists, is scrubbed).

Function Documentation

jwt_alg_str()

const char * jwt_alg_str

(

jwt_alg_t

alg

)

Convert alg type to it's string representation.

Returns a string that matches the alg type provided.

Parameters

alg	A valid jwt_alg_t specifier.

Returns

Returns a string (e.g. "RS256") matching the alg or NULL for invalid alg.

jwt_get_alg()

jwt_alg_t jwt_get_alg

(

const jwt_t *

jwt

)

Get the jwt_alg_t set for this JWT object.

Returns the jwt_alg_t type for this JWT object.

Warning

This is the alg for the jwt_t object and NOT the one that may be set in the header. This is a programatic check to see what LibJWT will use to encode the object into a JWT. To see what is embedded in the header, use jwt_get_header(jwt, "alg") instead.

Parameters

jwt	Pointer to a JWT object.

Returns

Returns a jwt_alg_t type for this object.

jwt_set_alg()

int jwt_set_alg	(	jwt_t *	jwt,
		jwt_alg_t	alg,
		const unsigned char *	key,
		int	len )

Set an algorithm for a jwt_t object.

Specifies an algorithm for a jwt_t object. If JWT_ALG_NONE is used, then key must be NULL and len must be 0. All other algorithms must have a valid pointer to key data, which may be specific to the algorithm (e.g RS256 expects a PEM formatted RSA key).

Parameters

jwt	Pointer to a jwt_t object.
alg	A valid jwt_alg_t specifier.
key	The key data to use for the algorithm.
len	The length of the key data.

Returns

Returns 0 on success, valid errno otherwise.

jwt_str_alg()

jwt_alg_t jwt_str_alg

(

const char *

alg

)

Convert alg string to type.

Returns an alg type based on the string representation.

RFC-7518 Sec 3.1

Parameters

alg	A valid string for algorithm type (e.g. "RS256").

Returns

Returns a jwt_alg_t matching the string or JWT_ALG_INVAL if no matches were found.

Note, this only works for algorithms that LibJWT supports or knows about.