text: // SPDX-License-Identifier: BSD-2-Clause
  /*
   * Copyright (c) 2015, Linaro Limited
   * All rights reserved.
   * Copyright (c) 2001-2007, Tom St Denis
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *
   * 1. Redistributions of source code must retain the above copyright notice,
   * this list of conditions and the following disclaimer.
   *
   * 2. 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.
   */
  
  /* LibTomCrypt, modular cryptographic library -- Tom St Denis
   *
   * LibTomCrypt is a library that provides various cryptographic
   * algorithms in a highly modular and flexible manner.
   *
   * The library is free for all purposes without any express
   * guarantee it works.
   *
   * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
   */
  #include <crypto/crypto_accel.h>
  #include <tomcrypt_private.h>
  
  #ifdef LTC_SHA256
  
  const struct ltc_hash_descriptor sha256_desc =
  {
      "sha256",
      0,
      32,
      64,
  
      /* OID */
     { 2, 16, 840, 1, 101, 3, 4, 2, 1,  },
     9,
  
      &sha256_init,
      &sha256_process,
      &sha256_done,
      &sha256_test,
      NULL
  };
  
  
  /* Implemented in assembly */
  int sha256_ce_transform(ulong32 *state, const unsigned char *buf, int blocks);
  
  static int sha256_compress_nblocks(hash_state *md, const unsigned char *buf,
  				   int blocks)
  {
     void *state = md->sha1.state;
  
     COMPILE_TIME_ASSERT(sizeof(md->sha1.state[0]) == sizeof(uint32_t));
  
      crypto_accel_sha256_compress(state, buf, blocks);
      return CRYPT_OK;
  }
  
  static int sha256_compress(hash_state *md, const unsigned char *buf)
  {
     return sha256_compress_nblocks(md, buf, 1);
  }
  
  /**
     Initialize the hash state
     @param md   The hash state you wish to initialize
     @return CRYPT_OK if successful
  */
  int sha256_init(hash_state * md)
  {
      LTC_ARGCHK(md != NULL);
  
      md->sha256.curlen = 0;
      md->sha256.length = 0;
      md->sha256.state[0] = 0x6A09E667UL;
      md->sha256.state[1] = 0xBB67AE85UL;
      md->sha256.state[2] = 0x3C6EF372UL;
      md->sha256.state[3] = 0xA54FF53AUL;
      md->sha256.state[4] = 0x510E527FUL;
      md->sha256.state[5] = 0x9B05688CUL;
      md->sha256.state[6] = 0x1F83D9ABUL;
      md->sha256.state[7] = 0x5BE0CD19UL;
      return CRYPT_OK;
  }
  
  /**
     Process a block of memory though the hash
     @param md     The hash state
     @param in     The data to hash
     @param inlen  The length of the data (octets)
     @return CRYPT_OK if successful
  */
  HASH_PROCESS_NBLOCKS(sha256_process, sha256_compress_nblocks, sha256, 64)
  
  /**
     Terminate the hash to get the digest
     @param md  The hash state
     @param out [out] The destination of the hash (32 bytes)
     @return CRYPT_OK if successful
  */
  int sha256_done(hash_state * md, unsigned char *out)
  {
      int i;
  
      LTC_ARGCHK(md  != NULL);
      LTC_ARGCHK(out != NULL);
  
      if (md->sha256.curlen >= sizeof(md->sha256.buf)) {
         return CRYPT_INVALID_ARG;
      }
  
  
      /* increase the length of the message */
      md->sha256.length += md->sha256.curlen * 8;
  
      /* append the '1' bit */
      md->sha256.buf[md->sha256.curlen++] = (unsigned char)0x80;
  
      /* if the length is currently above 56 bytes we append zeros
       * then compress.  Then we can fall back to padding zeros and length
       * encoding like normal.
       */
      if (md->sha256.curlen > 56) {
          while (md->sha256.curlen < 64) {
              md->sha256.buf[md->sha256.curlen++] = (unsigned char)0;
          }
          sha256_compress(md, md->sha256.buf);
          md->sha256.curlen = 0;
      }
  
      /* pad upto 56 bytes of zeroes */
      while (md->sha256.curlen < 56) {
          md->sha256.buf[md->sha256.curlen++] = (unsigned char)0;
      }
  
      /* store length */
      STORE64H(md->sha256.length, md->sha256.buf+56);
      sha256_compress(md, md->sha256.buf);
  
      /* copy output */
      for (i = 0; i < 8; i++) {
          STORE32H(md->sha256.state[i], out+(4*i));
      }
  #ifdef LTC_CLEAN_STACK
      zeromem(md, sizeof(hash_state));
  #endif
      return CRYPT_OK;
  }
  
  /**
    Self-test the hash
    @return CRYPT_OK if successful, CRYPT_NOP if self-tests have been disabled
  */
  int  sha256_test(void)
  {
   #ifndef LTC_TEST
      return CRYPT_NOP;
   #else
    static const struct {
        const char *msg;
        unsigned char hash[32];
    } tests[] = {
      { "abc",
        { 0xba, 0x78, 0x16, 0xbf, 0x8f, 0x01, 0xcf, 0xea,
          0x41, 0x41, 0x40, 0xde, 0x5d, 0xae, 0x22, 0x23,
          0xb0, 0x03, 0x61, 0xa3, 0x96, 0x17, 0x7a, 0x9c,
          0xb4, 0x10, 0xff, 0x61, 0xf2, 0x00, 0x15, 0xad }
      },
      { "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
        { 0x24, 0x8d, 0x6a, 0x61, 0xd2, 0x06, 0x38, 0xb8,
          0xe5, 0xc0, 0x26, 0x93, 0x0c, 0x3e, 0x60, 0x39,
          0xa3, 0x3c, 0xe4, 0x59, 0x64, 0xff, 0x21, 0x67,
          0xf6, 0xec, 0xed, 0xd4, 0x19, 0xdb, 0x06, 0xc1 }
      },
    };
  
    int i;
    unsigned char tmp[32];
    hash_state md;
  
    for (i = 0; i < (int)(sizeof(tests) / sizeof(tests[0])); i++) {
        sha256_init(&md);
        sha256_process(&md, (unsigned char*)tests[i].msg, (unsigned long)strlen(tests[i].msg));
        sha256_done(&md, tmp);
        if (XMEMCMP(tmp, tests[i].hash, 32) != 0) {
           return CRYPT_FAIL_TESTVECTOR;
        }
    }
    return CRYPT_OK;
   #endif
  }
  
  #endif /*LTC_SHA256*/
  