/* sha512.c

   The sha512 hash function.
   See http://csrc.nist.gov/publications/fips/fips180-4/fips-180-4.pdf

   Copyright (C) 2001, 2010 Niels Möller
   Copyright (C) 2014 Joachim Strömbergson

   This file is part of GNU Nettle.

   GNU Nettle is free software: you can redistribute it and/or
   modify it under the terms of either:

     * the GNU Lesser General Public License as published by the Free
       Software Foundation; either version 3 of the License, or (at your
       option) any later version.

   or

     * the GNU General Public License as published by the Free
       Software Foundation; either version 2 of the License, or (at your
       option) any later version.

   or both in parallel, as here.

   GNU Nettle is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received copies of the GNU General Public License and
   the GNU Lesser General Public License along with this program.  If
   not, see http://www.gnu.org/licenses/.
*/

/* Modelled after the sha1.c code by Peter Gutmann. */

#if HAVE_CONFIG_H
# include "config.h"
#endif

#include <assert.h>
#include <stdlib.h>
#include <string.h>

#include "sha2.h"

#include "macros.h"

/* Generated by the gp script

     {
       print("obase=16");
       for (i = 1,80,
         root = prime(i)^(1/3);
         fraction = root - floor(root);
         print(floor(2^64 * fraction));
       );
       quit();
     }

   piped through

     |grep -v '^[' | bc \
       |awk '{printf("0x%sULL,%s", $1, NR%3 == 0 ? "\n" : "");}'

   to convert it to hex.
*/

static const uint64_t
K[80] =
{
  0x428A2F98D728AE22ULL,0x7137449123EF65CDULL,
  0xB5C0FBCFEC4D3B2FULL,0xE9B5DBA58189DBBCULL,
  0x3956C25BF348B538ULL,0x59F111F1B605D019ULL,
  0x923F82A4AF194F9BULL,0xAB1C5ED5DA6D8118ULL,
  0xD807AA98A3030242ULL,0x12835B0145706FBEULL,
  0x243185BE4EE4B28CULL,0x550C7DC3D5FFB4E2ULL,
  0x72BE5D74F27B896FULL,0x80DEB1FE3B1696B1ULL,
  0x9BDC06A725C71235ULL,0xC19BF174CF692694ULL,
  0xE49B69C19EF14AD2ULL,0xEFBE4786384F25E3ULL,
  0x0FC19DC68B8CD5B5ULL,0x240CA1CC77AC9C65ULL,
  0x2DE92C6F592B0275ULL,0x4A7484AA6EA6E483ULL,
  0x5CB0A9DCBD41FBD4ULL,0x76F988DA831153B5ULL,
  0x983E5152EE66DFABULL,0xA831C66D2DB43210ULL,
  0xB00327C898FB213FULL,0xBF597FC7BEEF0EE4ULL,
  0xC6E00BF33DA88FC2ULL,0xD5A79147930AA725ULL,
  0x06CA6351E003826FULL,0x142929670A0E6E70ULL,
  0x27B70A8546D22FFCULL,0x2E1B21385C26C926ULL,
  0x4D2C6DFC5AC42AEDULL,0x53380D139D95B3DFULL,
  0x650A73548BAF63DEULL,0x766A0ABB3C77B2A8ULL,
  0x81C2C92E47EDAEE6ULL,0x92722C851482353BULL,
  0xA2BFE8A14CF10364ULL,0xA81A664BBC423001ULL,
  0xC24B8B70D0F89791ULL,0xC76C51A30654BE30ULL,
  0xD192E819D6EF5218ULL,0xD69906245565A910ULL,
  0xF40E35855771202AULL,0x106AA07032BBD1B8ULL,
  0x19A4C116B8D2D0C8ULL,0x1E376C085141AB53ULL,
  0x2748774CDF8EEB99ULL,0x34B0BCB5E19B48A8ULL,
  0x391C0CB3C5C95A63ULL,0x4ED8AA4AE3418ACBULL,
  0x5B9CCA4F7763E373ULL,0x682E6FF3D6B2B8A3ULL,
  0x748F82EE5DEFB2FCULL,0x78A5636F43172F60ULL,
  0x84C87814A1F0AB72ULL,0x8CC702081A6439ECULL,
  0x90BEFFFA23631E28ULL,0xA4506CEBDE82BDE9ULL,
  0xBEF9A3F7B2C67915ULL,0xC67178F2E372532BULL,
  0xCA273ECEEA26619CULL,0xD186B8C721C0C207ULL,
  0xEADA7DD6CDE0EB1EULL,0xF57D4F7FEE6ED178ULL,
  0x06F067AA72176FBAULL,0x0A637DC5A2C898A6ULL,
  0x113F9804BEF90DAEULL,0x1B710B35131C471BULL,
  0x28DB77F523047D84ULL,0x32CAAB7B40C72493ULL,
  0x3C9EBE0A15C9BEBCULL,0x431D67C49C100D4CULL,
  0x4CC5D4BECB3E42B6ULL,0x597F299CFC657E2AULL,
  0x5FCB6FAB3AD6FAECULL,0x6C44198C4A475817ULL,
};

#define COMPRESS(ctx, data) (_nettle_sha512_compress((ctx)->state, (data), K))

void
sha512_init(struct sha512_ctx *ctx)
{
  /* Initial values, generated by the gp script
       {
         for (i = 1,8,
	   root = prime(i)^(1/2);
	   fraction = root - floor(root);
	   print(floor(2^64 * fraction));
	 );
       }
. */
  static const uint64_t H0[_SHA512_DIGEST_LENGTH] =
  {
    0x6A09E667F3BCC908ULL,0xBB67AE8584CAA73BULL,
    0x3C6EF372FE94F82BULL,0xA54FF53A5F1D36F1ULL,
    0x510E527FADE682D1ULL,0x9B05688C2B3E6C1FULL,
    0x1F83D9ABFB41BD6BULL,0x5BE0CD19137E2179ULL,
  };

  memcpy(ctx->state, H0, sizeof(H0));

  /* Initialize bit count */
  ctx->count_low = ctx->count_high = 0;
  
  /* Initialize buffer */
  ctx->index = 0;
}

void
sha512_update(struct sha512_ctx *ctx,
	      size_t length, const uint8_t *data)
{
  MD_UPDATE (ctx, length, data, COMPRESS, MD_INCR(ctx));
}

static void
sha512_write_digest(struct sha512_ctx *ctx,
		    size_t length,
		    uint8_t *digest)
{
  uint64_t high, low;

  unsigned i;
  unsigned words;
  unsigned leftover;

  assert(length <= SHA512_DIGEST_SIZE);

  MD_PAD(ctx, 16, COMPRESS);

  /* There are 1024 = 2^10 bits in one block */  
  high = (ctx->count_high << 10) | (ctx->count_low >> 54);
  low = (ctx->count_low << 10) | (ctx->index << 3);

  /* This is slightly inefficient, as the numbers are converted to
     big-endian format, and will be converted back by the compression
     function. It's probably not worth the effort to fix this. */
  WRITE_UINT64(ctx->block + (SHA512_BLOCK_SIZE - 16), high);
  WRITE_UINT64(ctx->block + (SHA512_BLOCK_SIZE - 8), low);
  COMPRESS(ctx, ctx->block);

  words = length / 8;
  leftover = length % 8;

  for (i = 0; i < words; i++, digest += 8)
    WRITE_UINT64(digest, ctx->state[i]);

  if (leftover)
    {
      /* Truncate to the right size */
      uint64_t word = ctx->state[i] >> (8*(8 - leftover));

      do {
	digest[--leftover] = word & 0xff;
	word >>= 8;
      } while (leftover);
    }
}

void
sha512_digest(struct sha512_ctx *ctx,
	      size_t length,
	      uint8_t *digest)
{
  assert(length <= SHA512_DIGEST_SIZE);

  sha512_write_digest(ctx, length, digest);
  sha512_init(ctx);
}

/* sha384 variant. */
void
sha384_init(struct sha512_ctx *ctx)
{
  /* Initial values, generated by the gp script
       {
         for (i = 9,16,
	   root = prime(i)^(1/2);
	   fraction = root - floor(root);
	   print(floor(2^64 * fraction));
	 );
       }
. */
  static const uint64_t H0[_SHA512_DIGEST_LENGTH] =
  {
    0xCBBB9D5DC1059ED8ULL, 0x629A292A367CD507ULL,
    0x9159015A3070DD17ULL, 0x152FECD8F70E5939ULL,
    0x67332667FFC00B31ULL, 0x8EB44A8768581511ULL,
    0xDB0C2E0D64F98FA7ULL, 0x47B5481DBEFA4FA4ULL,
  };

  memcpy(ctx->state, H0, sizeof(H0));

  /* Initialize bit count */
  ctx->count_low = ctx->count_high = 0;
  
  /* Initialize buffer */
  ctx->index = 0;
}

void
sha384_digest(struct sha512_ctx *ctx,
	      size_t length,
	      uint8_t *digest)
{
  assert(length <= SHA384_DIGEST_SIZE);

  sha512_write_digest(ctx, length, digest);
  sha384_init(ctx);
}


/* sha-512/224 variant. */
void
sha512_224_init(struct sha512_224_ctx *ctx)
{
  static const uint64_t H0[_SHA512_DIGEST_LENGTH] =
  {
    0x8c3d37c819544da2ULL, 0x73e1996689dcd4d6ULL,
    0x1dfab7ae32ff9c82ULL, 0x679dd514582f9fcfULL,
    0x0f6d2b697bd44da8ULL, 0x77e36f7304c48942ULL,
    0x3f9d85a86a1d36c8ULL, 0x1112e6ad91d692a1ULL,
  };

  memcpy(ctx->state, H0, sizeof(H0));

  /* Initialize bit count */
  ctx->count_low = ctx->count_high = 0;
  
  /* Initialize buffer */
  ctx->index = 0;
}

void
sha512_224_digest(struct sha512_224_ctx *ctx,
	      size_t length,
	      uint8_t *digest)
{
  assert(length <= SHA224_DIGEST_SIZE);

  sha512_write_digest(ctx, length, digest);
  sha512_224_init(ctx);
}


/* sha-512/256 variant. */
void
sha512_256_init(struct sha512_256_ctx *ctx)
{
  static const uint64_t H0[_SHA512_DIGEST_LENGTH] =
    {
      0x22312194fc2bf72cULL, 0x9f555fa3c84c64c2ULL, 
      0x2393b86b6f53b151ULL, 0x963877195940eabdULL, 
      0x96283ee2a88effe3ULL, 0xbe5e1e2553863992ULL, 
      0x2b0199fc2c85b8aaULL, 0x0eb72ddc81c52ca2ULL,
    };

  memcpy(ctx->state, H0, sizeof(H0));

  /* Initialize bit count */
  ctx->count_low = ctx->count_high = 0;
  
  /* Initialize buffer */
  ctx->index = 0;
}

void
sha512_256_digest(struct sha512_256_ctx *ctx,
	      size_t length,
	      uint8_t *digest)
{
  assert(length <= SHA256_DIGEST_SIZE);

  sha512_write_digest(ctx, length, digest);
  sha512_256_init(ctx);
}