/* mac.h */

typedef struct UMAC_CTX *umac_ctx_t;

umac_ctx_t umac_new(char key[]);
/* Dynamically allocate a umac_ctx struct, initialize variables, 
 * generate subkeys from key.
 */

int umac_reset(umac_ctx_t ctx);
/* Reset a umac_ctx to begin authenicating a new message */

int umac_update(umac_ctx_t ctx, char *input, long len);
/* Incorporate len bytes pointed to by input into context ctx */

int umac_final(umac_ctx_t ctx, char tag[], char nonce[8]);
/* Incorporate any pending data and the ctr value, and return tag. 
 * This function returns error code if ctr < 0. 
 */

int umac_delete(umac_ctx_t ctx);
/* Deallocate the context structure */

int umac(umac_ctx_t ctx, char *input, 
         long len, char tag[],
         char nonce[8]);
/* All-in-one implementation of the functions Reset, Update and Final */