/* sha512.c - an implementation of SHA-384/512 hash functions

 * based on FIPS 180-3 (Federal Information Processing Standart).

 *

 * Copyright (c) 2010, Aleksey Kravchenko <rhash.admin@gmail.com>

 *

 * Permission to use, copy, modify, and/or distribute this software for any

 * purpose with or without fee is hereby granted.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH

 * REGARD TO THIS SOFTWARE  INCLUDING ALL IMPLIED WARRANTIES OF  MERCHANTABILITY

 * AND FITNESS.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,

 * INDIRECT,  OR CONSEQUENTIAL DAMAGES  OR ANY DAMAGES WHATSOEVER RESULTING FROM

 * LOSS OF USE,  DATA OR PROFITS,  WHETHER IN AN ACTION OF CONTRACT,  NEGLIGENCE

 * OR OTHER TORTIOUS ACTION,  ARISING OUT OF  OR IN CONNECTION  WITH THE USE  OR

 * PERFORMANCE OF THIS SOFTWARE.

 */

#include <string.h>

#include "byte_order.h"

#include "sha512.h"

/* SHA-384 and SHA-512 constants for 80 rounds. These qwords represent

 * the first 64 bits of the fractional parts of the cube

 * roots of the first 80 prime numbers. */

static const uint64_t rhash_k512[80] = {

  I64(0x428a2f98d728ae22), I64(0x7137449123ef65cd), I64(0xb5c0fbcfec4d3b2f),

  I64(0xe9b5dba58189dbbc), I64(0x3956c25bf348b538), I64(0x59f111f1b605d019),

  I64(0x923f82a4af194f9b), I64(0xab1c5ed5da6d8118), I64(0xd807aa98a3030242),

  I64(0x12835b0145706fbe), I64(0x243185be4ee4b28c), I64(0x550c7dc3d5ffb4e2),

  I64(0x72be5d74f27b896f), I64(0x80deb1fe3b1696b1), I64(0x9bdc06a725c71235),

  I64(0xc19bf174cf692694), I64(0xe49b69c19ef14ad2), I64(0xefbe4786384f25e3),

  I64(0x0fc19dc68b8cd5b5), I64(0x240ca1cc77ac9c65), I64(0x2de92c6f592b0275),

  I64(0x4a7484aa6ea6e483), I64(0x5cb0a9dcbd41fbd4), I64(0x76f988da831153b5),

  I64(0x983e5152ee66dfab), I64(0xa831c66d2db43210), I64(0xb00327c898fb213f),

  I64(0xbf597fc7beef0ee4), I64(0xc6e00bf33da88fc2), I64(0xd5a79147930aa725),

  I64(0x06ca6351e003826f), I64(0x142929670a0e6e70), I64(0x27b70a8546d22ffc),

  I64(0x2e1b21385c26c926), I64(0x4d2c6dfc5ac42aed), I64(0x53380d139d95b3df),

  I64(0x650a73548baf63de), I64(0x766a0abb3c77b2a8), I64(0x81c2c92e47edaee6),

  I64(0x92722c851482353b), I64(0xa2bfe8a14cf10364), I64(0xa81a664bbc423001),

  I64(0xc24b8b70d0f89791), I64(0xc76c51a30654be30), I64(0xd192e819d6ef5218),

  I64(0xd69906245565a910), I64(0xf40e35855771202a), I64(0x106aa07032bbd1b8),

  I64(0x19a4c116b8d2d0c8), I64(0x1e376c085141ab53), I64(0x2748774cdf8eeb99),

  I64(0x34b0bcb5e19b48a8), I64(0x391c0cb3c5c95a63), I64(0x4ed8aa4ae3418acb),

  I64(0x5b9cca4f7763e373), I64(0x682e6ff3d6b2b8a3), I64(0x748f82ee5defb2fc),

  I64(0x78a5636f43172f60), I64(0x84c87814a1f0ab72), I64(0x8cc702081a6439ec),

  I64(0x90befffa23631e28), I64(0xa4506cebde82bde9), I64(0xbef9a3f7b2c67915),

  I64(0xc67178f2e372532b), I64(0xca273eceea26619c), I64(0xd186b8c721c0c207),

  I64(0xeada7dd6cde0eb1e), I64(0xf57d4f7fee6ed178), I64(0x06f067aa72176fba),

  I64(0x0a637dc5a2c898a6), I64(0x113f9804bef90dae), I64(0x1b710b35131c471b),

  I64(0x28db77f523047d84), I64(0x32caab7b40c72493), I64(0x3c9ebe0a15c9bebc),

  I64(0x431d67c49c100d4c), I64(0x4cc5d4becb3e42b6), I64(0x597f299cfc657e2a),

  I64(0x5fcb6fab3ad6faec), I64(0x6c44198c4a475817)

};

/* The SHA512/384 functions defined by FIPS 180-3, 4.1.3 */

/* Optimized version of Ch(x,y,z)=((x & y) | (~x & z)) */

#define Ch(x,y,z)  ((z) ^ ((x) & ((y) ^ (z))))

/* Optimized version of Maj(x,y,z)=((x & y) ^ (x & z) ^ (y & z)) */

#define Maj(x,y,z) (((x) & (y)) ^ ((z) & ((x) ^ (y))))

#define Sigma0(x) (ROTR64((x), 28) ^ ROTR64((x), 34) ^ ROTR64((x), 39))

#define Sigma1(x) (ROTR64((x), 14) ^ ROTR64((x), 18) ^ ROTR64((x), 41))

#define sigma0(x) (ROTR64((x),  1) ^ ROTR64((x),  8) ^ ((x) >> 7))

#define sigma1(x) (ROTR64((x), 19) ^ ROTR64((x), 61) ^ ((x) >> 6))

/* Recalculate element n-th of circular buffer W using formula

 *   W[n] = sigma1(W[n - 2]) + W[n - 7] + sigma0(W[n - 15]) + W[n - 16]; */

#define RECALCULATE_W(W,n) (W[n] += \

  (sigma1(W[(n - 2) & 15]) + W[(n - 7) & 15] + sigma0(W[(n - 15) & 15])))

#define ROUND(a,b,c,d,e,f,g,h,k,data) { \

  uint64_t T1 = h + Sigma1(e) + Ch(e,f,g) + k + (data); \

  d += T1, h = T1 + Sigma0(a) + Maj(a,b,c); }

#define ROUND_1_16(a,b,c,d,e,f,g,h,n) \

  ROUND(a,b,c,d,e,f,g,h, rhash_k512[n], W[n] = be2me_64(block[n]))

#define ROUND_17_80(a,b,c,d,e,f,g,h,n) \

  ROUND(a,b,c,d,e,f,g,h, k[n], RECALCULATE_W(W, n))

/**

 * Initialize context before calculating hash.

 *

 * @param ctx context to initialize

 */

void rhash_sha512_init(sha512_ctx* ctx)

{

  /* Initial values. These words were obtained by taking the first 32

   * bits of the fractional parts of the square roots of the first

   * eight prime numbers. */

  static const uint64_t SHA512_H0[8] = {

    I64(0x6a09e667f3bcc908), I64(0xbb67ae8584caa73b), I64(0x3c6ef372fe94f82b),

    I64(0xa54ff53a5f1d36f1), I64(0x510e527fade682d1), I64(0x9b05688c2b3e6c1f),

    I64(0x1f83d9abfb41bd6b), I64(0x5be0cd19137e2179)

  };

  memset(ctx->message, 0, sizeof(ctx->message));

  ctx->length = 0;

  ctx->digest_length = sha512_hash_size;

  /* initialize algorithm state */

  memcpy(ctx->hash, SHA512_H0, sizeof(ctx->hash));

}

/**

 * Initialize context before calculating hash.

 *

 * @param ctx context to initialize

 */

void rhash_sha384_init(struct sha512_ctx* ctx)

{

  /* Initial values from FIPS 180-3. These words were obtained by taking

   * the first sixty-four bits of the fractional parts of the square

   * roots of ninth through sixteenth prime numbers. */

  static const uint64_t SHA384_H0[8] = {

    I64(0xcbbb9d5dc1059ed8), I64(0x629a292a367cd507), I64(0x9159015a3070dd17),

    I64(0x152fecd8f70e5939), I64(0x67332667ffc00b31), I64(0x8eb44a8768581511),

    I64(0xdb0c2e0d64f98fa7), I64(0x47b5481dbefa4fa4)

  };

  memset(ctx->message, 0, sizeof(ctx->message));

  ctx->length = 0;

  ctx->digest_length = sha384_hash_size;

  memcpy(ctx->hash, SHA384_H0, sizeof(ctx->hash));

}

/**

 * The core transformation. Process a 512-bit block.

 *

 * @param hash algorithm state

 * @param block the message block to process

 */

static void rhash_sha512_process_block(uint64_t hash[8], uint64_t block[16])

{

  uint64_t A, B, C, D, E, F, G, H;

  uint64_t W[16];

  const uint64_t* k;

  int i;

  A = hash[0], B = hash[1], C = hash[2], D = hash[3];

  E = hash[4], F = hash[5], G = hash[6], H = hash[7];

  /* Compute SHA using alternate Method: FIPS 180-3 6.1.3 */

  ROUND_1_16(A, B, C, D, E, F, G, H, 0);

  ROUND_1_16(H, A, B, C, D, E, F, G, 1);

  ROUND_1_16(G, H, A, B, C, D, E, F, 2);

  ROUND_1_16(F, G, H, A, B, C, D, E, 3);

  ROUND_1_16(E, F, G, H, A, B, C, D, 4);

  ROUND_1_16(D, E, F, G, H, A, B, C, 5);

  ROUND_1_16(C, D, E, F, G, H, A, B, 6);

  ROUND_1_16(B, C, D, E, F, G, H, A, 7);

  ROUND_1_16(A, B, C, D, E, F, G, H, 8);

  ROUND_1_16(H, A, B, C, D, E, F, G, 9);

  ROUND_1_16(G, H, A, B, C, D, E, F, 10);

  ROUND_1_16(F, G, H, A, B, C, D, E, 11);

  ROUND_1_16(E, F, G, H, A, B, C, D, 12);

  ROUND_1_16(D, E, F, G, H, A, B, C, 13);

  ROUND_1_16(C, D, E, F, G, H, A, B, 14);

  ROUND_1_16(B, C, D, E, F, G, H, A, 15);

  for (i = 16, k = &rhash_k512[16]; i < 80; i += 16, k += 16) {

    ROUND_17_80(A, B, C, D, E, F, G, H,  0);

    ROUND_17_80(H, A, B, C, D, E, F, G,  1);

    ROUND_17_80(G, H, A, B, C, D, E, F,  2);

    ROUND_17_80(F, G, H, A, B, C, D, E,  3);

    ROUND_17_80(E, F, G, H, A, B, C, D,  4);

    ROUND_17_80(D, E, F, G, H, A, B, C,  5);

    ROUND_17_80(C, D, E, F, G, H, A, B,  6);

    ROUND_17_80(B, C, D, E, F, G, H, A,  7);

    ROUND_17_80(A, B, C, D, E, F, G, H,  8);

    ROUND_17_80(H, A, B, C, D, E, F, G,  9);

    ROUND_17_80(G, H, A, B, C, D, E, F, 10);

    ROUND_17_80(F, G, H, A, B, C, D, E, 11);

    ROUND_17_80(E, F, G, H, A, B, C, D, 12);

    ROUND_17_80(D, E, F, G, H, A, B, C, 13);

    ROUND_17_80(C, D, E, F, G, H, A, B, 14);

    ROUND_17_80(B, C, D, E, F, G, H, A, 15);

  }

  hash[0] += A, hash[1] += B, hash[2] += C, hash[3] += D;

  hash[4] += E, hash[5] += F, hash[6] += G, hash[7] += H;

}

/**

 * Calculate message hash.

 * Can be called repeatedly with chunks of the message to be hashed.

 *

 * @param ctx the algorithm context containing current hashing state

 * @param msg message chunk

 * @param size length of the message chunk

 */

void rhash_sha512_update(sha512_ctx* ctx, const unsigned char* msg, size_t size)

{

  size_t index = (size_t)ctx->length & 127;

  ctx->length += size;

  /* fill partial block */

  if (index) {

    size_t left = sha512_block_size - index;

    memcpy((char*)ctx->message + index, msg, (size < left ? size : left));

    if (size < left) return;

    /* process partial block */

    rhash_sha512_process_block(ctx->hash, ctx->message);

    msg  += left;

    size -= left;

  }

  while (size >= sha512_block_size) {

    uint64_t* aligned_message_block;

    if (IS_ALIGNED_64(msg)) {

      /* the most common case is processing of an already aligned message

      without copying it */

      aligned_message_block = (uint64_t*)msg;

    } else {

      memcpy(ctx->message, msg, sha512_block_size);

      aligned_message_block = ctx->message;

    }

    rhash_sha512_process_block(ctx->hash, aligned_message_block);

    msg  += sha512_block_size;

    size -= sha512_block_size;

  }

  if (size) {

    memcpy(ctx->message, msg, size); /* save leftovers */

  }

}

/**

 * Store calculated hash into the given array.

 *

 * @param ctx the algorithm context containing current hashing state

 * @param result calculated hash in binary form

 */

void rhash_sha512_final(sha512_ctx* ctx, unsigned char* result)

{

  size_t index = ((unsigned)ctx->length & 127) >> 3;

  unsigned shift = ((unsigned)ctx->length & 7) * 8;

  /* pad message and process the last block */

  /* append the byte 0x80 to the message */

  ctx->message[index]   &= le2me_64( ~(I64(0xFFFFFFFFFFFFFFFF) << shift) );

  ctx->message[index++] ^= le2me_64( I64(0x80) << shift );

  /* if no room left in the message to store 128-bit message length */

  if (index >= 15) {

    if (index == 15) ctx->message[index] = 0;

    rhash_sha512_process_block(ctx->hash, ctx->message);

    index = 0;

  }

  while (index < 15) {

    ctx->message[index++] = 0;

  }

  ctx->message[15] = be2me_64(ctx->length << 3);

  rhash_sha512_process_block(ctx->hash, ctx->message);

  if (result) be64_copy(result, 0, ctx->hash, ctx->digest_length);

}