tc_ctr_prng.h

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/* ctr_prng.h - TinyCrypt interface to a CTR-PRNG implementation */

/*
 * Copyright (c) 2016, Chris Morrison
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice, 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef __TC_CTR_PRNG_H__
#define __TC_CTR_PRNG_H__

#include "tc_aes.h"

#define TC_CTR_PRNG_RESEED_REQ -1

#ifdef __cplusplus
extern "C" {
#endif

typedef struct {
  /* updated each time another BLOCKLEN_BYTES bytes are produced */
  uint8_t V[TC_AES_BLOCK_SIZE];

  /* updated whenever the PRNG is reseeded */
  struct tc_aes_key_sched_struct key;

  /* number of requests since initialization/reseeding */
  uint64_t reseedCount;
} TCCtrPrng_t;


int tc_ctr_prng_init(TCCtrPrng_t * const ctx,
         uint8_t const * const entropy,
         unsigned int entropyLen,
         uint8_t const * const personalization,
         unsigned int pLen);

int tc_ctr_prng_reseed(TCCtrPrng_t * const ctx,
           uint8_t const * const entropy,
           unsigned int entropyLen,
           uint8_t const * const additional_input,
           unsigned int additionallen);

int tc_ctr_prng_generate(TCCtrPrng_t * const ctx,
       uint8_t const * const additional_input,
       unsigned int additionallen,
       uint8_t * const out,
       unsigned int outlen);

void tc_ctr_prng_uninstantiate(TCCtrPrng_t * const ctx);

#ifdef __cplusplus
}
#endif

#endif /* __TC_CTR_PRNG_H__ */