tc_hmac.c File Reference

#include "tc_hmac.h"
#include "tc_constants.h"
#include "tc_utils.h"

Functions
static void	rekey (uint8_t *key, const uint8_t *new_key, unsigned int key_size)
int	tc_hmac_set_key (TCHmacState_t ctx, const uint8_t *key, unsigned int key_size)
	HMAC set key procedure Configures ctx to use key. More...
int	tc_hmac_init (TCHmacState_t ctx)
	HMAC init procedure Initializes ctx to begin the next HMAC operation. More...
int	tc_hmac_update (TCHmacState_t ctx, const void *data, unsigned int data_length)
	HMAC update procedure Mixes data_length bytes addressed by data into state. More...
int	tc_hmac_final (uint8_t *tag, unsigned int taglen, TCHmacState_t ctx)
	HMAC final procedure Writes the HMAC tag into the tag buffer. More...

Function Documentation

rekey()

static void rekey ( uint8_t *  key, const uint8_t *  new_key, unsigned int  key_size  )

static

tc_hmac_final()

int tc_hmac_final	(	uint8_t *	tag,
		unsigned int	taglen,
		TCHmacState_t	ctx
	)

HMAC final procedure Writes the HMAC tag into the tag buffer.

Returns

returns TC_CRYPTO_SUCCESS (1) returns TC_CRYPTO_FAIL (0) if: tag == NULL or ctx == NULL or key == NULL or taglen != TC_SHA256_DIGEST_SIZE

Note

ctx is erased before exiting. This should never be changed/removed.

Assumes the tag bufer is at least sizeof(hmac_tag_size(state)) bytes state has been initialized by tc_hmac_init

Parameters

tag	IN/OUT – buffer to receive computed HMAC tag
taglen	IN – size of tag in bytes
ctx	IN/OUT – the HMAC state for computing tag

tc_hmac_init()

int tc_hmac_init

(

TCHmacState_t

ctx

)

HMAC init procedure Initializes ctx to begin the next HMAC operation.

Returns

returns TC_CRYPTO_SUCCESS (1) returns TC_CRYPTO_FAIL (0) if: ctx == NULL or key == NULL

Parameters

ctx	IN/OUT – struct tc_hmac_state_struct buffer to init

tc_hmac_set_key()

int tc_hmac_set_key	(	TCHmacState_t	ctx,
		const uint8_t *	key,
		unsigned int	key_size
	)

HMAC set key procedure Configures ctx to use key.

Returns

returns TC_CRYPTO_SUCCESS (1) returns TC_CRYPTO_FAIL (0) if ctx == NULL or key == NULL or key_size == 0

Parameters

ctx	IN/OUT – the struct tc_hmac_state_struct to initial
key	IN – the HMAC key to configure
key_size	IN – the HMAC key size

tc_hmac_update()

int tc_hmac_update	(	TCHmacState_t	ctx,
		const void *	data,
		unsigned int	data_length
	)

HMAC update procedure Mixes data_length bytes addressed by data into state.

Returns

returns TC_CRYPTO_SUCCCESS (1) returns TC_CRYPTO_FAIL (0) if: ctx == NULL or key == NULL

Note

Assumes state has been initialized by tc_hmac_init

Parameters

ctx	IN/OUT – state of HMAC computation so far
data	IN – data to incorporate into state
data_length	IN – size of data in bytes