/* ripemd160.c  -  RIPE-MD160 */

/* nettle, low-level cryptographics library
 *
 * Copyright (C) 1998, 2001, 2002, 2003 Free Software Foundation, Inc.
 * Copyright (C) 2011 Niels Möller
 *
 * The nettle library is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at your
 * option) any later version.
 *
 * The nettle library 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 Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with the nettle library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02111-1301, USA.
 */

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

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

#include "ripemd160.h"

#include "macros.h"
#include "nettle-write.h"

/*********************************
 * RIPEMD-160 is not patented, see (as of 2011-08-28)
 *   http://www.esat.kuleuven.ac.be/~bosselae/ripemd160.html
 * Note that the code uses Little Endian byteorder, which is good for
 * 386 etc, but we must add some conversion when used on a big endian box.
 *
 *
 * Pseudo-code for RIPEMD-160
 *
 * RIPEMD-160 is an iterative hash function that operates on 32-bit words.
 * The round function takes as input a 5-word chaining variable and a 16-word
 * message block and maps this to a new chaining variable. All operations are
 * defined on 32-bit words. Padding is identical to that of MD4.
 *
 *
 * RIPEMD-160: definitions
 *
 *
 *   nonlinear functions at bit level: exor, mux, -, mux, -
 *
 *   f(j, x, y, z) = x XOR y XOR z      (0 <= j <= 15)
 *   f(j, x, y, z) = (x AND y) OR (NOT(x) AND z)  (16 <= j <= 31)
 *   f(j, x, y, z) = (x OR NOT(y)) XOR z    (32 <= j <= 47)
 *   f(j, x, y, z) = (x AND z) OR (y AND NOT(z))  (48 <= j <= 63)
 *   f(j, x, y, z) = x XOR (y OR NOT(z))    (64 <= j <= 79)
 *
 *
 *   added constants (hexadecimal)
 *
 *   K(j) = 0x00000000      (0 <= j <= 15)
 *   K(j) = 0x5A827999     (16 <= j <= 31)  int(2**30 x sqrt(2))
 *   K(j) = 0x6ED9EBA1     (32 <= j <= 47)  int(2**30 x sqrt(3))
 *   K(j) = 0x8F1BBCDC     (48 <= j <= 63)  int(2**30 x sqrt(5))
 *   K(j) = 0xA953FD4E     (64 <= j <= 79)  int(2**30 x sqrt(7))
 *   K'(j) = 0x50A28BE6     (0 <= j <= 15)      int(2**30 x cbrt(2))
 *   K'(j) = 0x5C4DD124    (16 <= j <= 31)      int(2**30 x cbrt(3))
 *   K'(j) = 0x6D703EF3    (32 <= j <= 47)      int(2**30 x cbrt(5))
 *   K'(j) = 0x7A6D76E9    (48 <= j <= 63)      int(2**30 x cbrt(7))
 *   K'(j) = 0x00000000    (64 <= j <= 79)
 *
 *
 *   selection of message word
 *
 *   r(j)      = j          (0 <= j <= 15)
 *   r(16..31) = 7, 4, 13, 1, 10, 6, 15, 3, 12, 0, 9, 5, 2, 14, 11, 8
 *   r(32..47) = 3, 10, 14, 4, 9, 15, 8, 1, 2, 7, 0, 6, 13, 11, 5, 12
 *   r(48..63) = 1, 9, 11, 10, 0, 8, 12, 4, 13, 3, 7, 15, 14, 5, 6, 2
 *   r(64..79) = 4, 0, 5, 9, 7, 12, 2, 10, 14, 1, 3, 8, 11, 6, 15, 13
 *   r0(0..15) = 5, 14, 7, 0, 9, 2, 11, 4, 13, 6, 15, 8, 1, 10, 3, 12
 *   r0(16..31)= 6, 11, 3, 7, 0, 13, 5, 10, 14, 15, 8, 12, 4, 9, 1, 2
 *   r0(32..47)= 15, 5, 1, 3, 7, 14, 6, 9, 11, 8, 12, 2, 10, 0, 4, 13
 *   r0(48..63)= 8, 6, 4, 1, 3, 11, 15, 0, 5, 12, 2, 13, 9, 7, 10, 14
 *   r0(64..79)= 12, 15, 10, 4, 1, 5, 8, 7, 6, 2, 13, 14, 0, 3, 9, 11
 *
 *
 *   amount for rotate left (rol)
 *
 *   s(0..15)  = 11, 14, 15, 12, 5, 8, 7, 9, 11, 13, 14, 15, 6, 7, 9, 8
 *   s(16..31) = 7, 6, 8, 13, 11, 9, 7, 15, 7, 12, 15, 9, 11, 7, 13, 12
 *   s(32..47) = 11, 13, 6, 7, 14, 9, 13, 15, 14, 8, 13, 6, 5, 12, 7, 5
 *   s(48..63) = 11, 12, 14, 15, 14, 15, 9, 8, 9, 14, 5, 6, 8, 6, 5, 12
 *   s(64..79) = 9, 15, 5, 11, 6, 8, 13, 12, 5, 12, 13, 14, 11, 8, 5, 6
 *   s'(0..15) = 8, 9, 9, 11, 13, 15, 15, 5, 7, 7, 8, 11, 14, 14, 12, 6
 *   s'(16..31)= 9, 13, 15, 7, 12, 8, 9, 11, 7, 7, 12, 7, 6, 15, 13, 11
 *   s'(32..47)= 9, 7, 15, 11, 8, 6, 6, 14, 12, 13, 5, 14, 13, 13, 7, 5
 *   s'(48..63)= 15, 5, 8, 11, 14, 14, 6, 14, 6, 9, 12, 9, 12, 5, 15, 8
 *   s'(64..79)= 8, 5, 12, 9, 12, 5, 14, 6, 8, 13, 6, 5, 15, 13, 11, 11
 *
 *
 *   initial value (hexadecimal)
 *
 *   h0 = 0x67452301; h1 = 0xEFCDAB89; h2 = 0x98BADCFE; h3 = 0x10325476;
 *              h4 = 0xC3D2E1F0;
 *
 *
 * RIPEMD-160: pseudo-code
 *
 *   It is assumed that the message after padding consists of t 16-word blocks
 *   that will be denoted with X[i][j], with 0 <= i <= t-1 and 0 <= j <= 15.
 *   The symbol [+] denotes addition modulo 2**32 and rol_s denotes cyclic left
 *   shift (rotate) over s positions.
 *
 *
 *   for i := 0 to t-1 {
 *   A := h0; B := h1; C := h2; D = h3; E = h4;
 *   A' := h0; B' := h1; C' := h2; D' = h3; E' = h4;
 *   for j := 0 to 79 {
 *       T := rol_s(j)(A [+] f(j, B, C, D) [+] X[i][r(j)] [+] K(j)) [+] E;
 *       A := E; E := D; D := rol_10(C); C := B; B := T;
 *       T := rol_s'(j)(A' [+] f(79-j, B', C', D') [+] X[i][r'(j)]
                   [+] K'(j)) [+] E';
 *       A' := E'; E' := D'; D' := rol_10(C'); C' := B'; B' := T;
 *   }
 *   T := h1 [+] C [+] D'; h1 := h2 [+] D [+] E'; h2 := h3 [+] E [+] A';
 *   h3 := h4 [+] A [+] B'; h4 := h0 [+] B [+] C'; h0 := T;
 *   }
 */

/* Some examples:
 * ""                    9c1185a5c5e9fc54612808977ee8f548b2258d31
 * "a"                   0bdc9d2d256b3ee9daae347be6f4dc835a467ffe
 * "abc"                 8eb208f7e05d987a9b044a8e98c6b087f15a0bfc
 * "message digest"      5d0689ef49d2fae572b881b123a85ffa21595f36
 * "a...z"               f71c27109c692c1b56bbdceb5b9d2865b3708dbc
 * "abcdbcde...nopq"     12a053384a9c0c88e405a06c27dcf49ada62eb2b
 * "A...Za...z0...9"     b0e20b6e3116640286ed3a87a5713079b21f5189
 * 8 times "1234567890"  9b752e45573d4b39f4dbd3323cab82bf63326bfb
 * 1 million times "a"   52783243c1697bdbe16d37f97f68f08325dc1528
 */

void
ripemd160_init(struct ripemd160_ctx *ctx)
{
  static const uint32_t iv[_RIPEMD160_DIGEST_LENGTH] =
    {
      0x67452301,
      0xEFCDAB89,
      0x98BADCFE,
      0x10325476,
      0xC3D2E1F0,
    };
  memcpy(ctx->state, iv, sizeof(ctx->state));
  ctx->count_low = ctx->count_high = 0;
  ctx->index = 0;
}

#define COMPRESS(ctx, data) (_nettle_ripemd160_compress((ctx)->state, (data)))

/* Update the message digest with the contents
 * of DATA with length LENGTH.
 */
void
ripemd160_update(struct ripemd160_ctx *ctx, unsigned length, const uint8_t *data)
{
  MD_UPDATE(ctx, length, data, COMPRESS, MD_INCR(ctx));
}

void
ripemd160_digest(struct ripemd160_ctx *ctx, unsigned length, uint8_t *digest)
{
  uint32_t high, low;

  assert(length <= RIPEMD160_DIGEST_SIZE);

  MD_PAD(ctx, 8, COMPRESS);

  /* There are 2^9 bits in one block */
  high = (ctx->count_high << 9) | (ctx->count_low >> 23);
  low = (ctx->count_low << 9) | (ctx->index << 3);
									\
  /* append the 64 bit count */
  LE_WRITE_UINT32(ctx->block + 56, low);
  LE_WRITE_UINT32(ctx->block + 60, high);
  _nettle_ripemd160_compress(ctx->state, ctx->block);

  _nettle_write_le32(length, digest, ctx->state);
  ripemd160_init(ctx);
}
