tc_cmac_mode.h

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/*  cmac_mode.h -- interface to a CMAC implementation */

/*
 *  Copyright (C) 2017 by Intel Corporation, All Rights Reserved
 *
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 *  modification, are permitted provided that the following conditions are met:
 *
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 *     this list of conditions and the following disclaimer.
 *
 *    - Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 *    - Neither the name of Intel Corporation nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 */

#ifndef __TC_CMAC_MODE_H__
#define __TC_CMAC_MODE_H__

#include "tc_aes.h"

#include <stddef.h>

#ifdef __cplusplus
extern "C" {
#endif

/* padding for last message block */
#define TC_CMAC_PADDING 0x80

/* struct tc_cmac_struct represents the state of a CMAC computation */
typedef struct tc_cmac_struct {
/* initialization vector */
  uint8_t iv[TC_AES_BLOCK_SIZE];
/* used if message length is a multiple of block_size bytes */
  uint8_t K1[TC_AES_BLOCK_SIZE];
/* used if message length isn't a multiple block_size bytes */
  uint8_t K2[TC_AES_BLOCK_SIZE];
/* where to put bytes that didn't fill a block */
  uint8_t leftover[TC_AES_BLOCK_SIZE];
/* identifies the encryption key */
  unsigned int keyid;
/* next available leftover location */
  unsigned int leftover_offset;
/* AES key schedule */
  TCAesKeySched_t sched;
/* calls to tc_cmac_update left before re-key */
  uint64_t countdown;
} *TCCmacState_t;

int tc_cmac_setup(TCCmacState_t s, const uint8_t *key,
          TCAesKeySched_t sched);

int tc_cmac_erase(TCCmacState_t s);

int tc_cmac_init(TCCmacState_t s);

int tc_cmac_update(TCCmacState_t s, const uint8_t *data, size_t dlen);

int tc_cmac_final(uint8_t *tag, TCCmacState_t s);

#ifdef __cplusplus
}
#endif

#endif /* __TC_CMAC_MODE_H__ */