src/crypto/fips_prf_openssl.c

   1 /*
   2  * FIPS 186-2 PRF for libcrypto
   3  * Copyright (c) 2004-2005, Jouni Malinen <j@w1.fi>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * Alternatively, this software may be distributed under the terms of BSD
  10  * license.
  11  *
  12  * See README and COPYING for more details.
  13  */
  14
  15 #include "includes.h"
  16 #include <openssl/sha.h>
  17
  18 #include "common.h"
  19 #include "crypto.h"
  20
  21
  22 static void sha1_transform(u8 *state, const u8 data[64])
  23 {
  24         SHA_CTX context;
  25         os_memset(&context, 0, sizeof(context));
  26         os_memcpy(&context.h0, state, 5 * 4);
  27         SHA1_Transform(&context, data);
  28         os_memcpy(state, &context.h0, 5 * 4);
  29 }
  30
  31
  32 int fips186_2_prf(const u8 *seed, size_t seed_len, u8 *x, size_t xlen)
  33 {
  34         u8 xkey[64];
  35         u32 t[5], _t[5];
  36         int i, j, m, k;
  37         u8 *xpos = x;
  38         u32 carry;
  39
  40         if (seed_len > sizeof(xkey))
  41                 seed_len = sizeof(xkey);
  42
  43         /* FIPS 186-2 + change notice 1 */
  44
  45         os_memcpy(xkey, seed, seed_len);
  46         os_memset(xkey + seed_len, 0, 64 - seed_len);
  47         t[0] = 0x67452301;
  48         t[1] = 0xEFCDAB89;
  49         t[2] = 0x98BADCFE;
  50         t[3] = 0x10325476;
  51         t[4] = 0xC3D2E1F0;
  52
  53         m = xlen / 40;
  54         for (j = 0; j < m; j++) {
  55                 /* XSEED_j = 0 */
  56                 for (i = 0; i < 2; i++) {
  57                         /* XVAL = (XKEY + XSEED_j) mod 2^b */
  58
  59                         /* w_i = G(t, XVAL) */
  60                         os_memcpy(_t, t, 20);
  61                         sha1_transform((u8 *) _t, xkey);
  62                         _t[0] = host_to_be32(_t[0]);
  63                         _t[1] = host_to_be32(_t[1]);
  64                         _t[2] = host_to_be32(_t[2]);
  65                         _t[3] = host_to_be32(_t[3]);
  66                         _t[4] = host_to_be32(_t[4]);
  67                         os_memcpy(xpos, _t, 20);
  68
  69                         /* XKEY = (1 + XKEY + w_i) mod 2^b */
  70                         carry = 1;
  71                         for (k = 19; k >= 0; k--) {
  72                                 carry += xkey[k] + xpos[k];
  73                                 xkey[k] = carry & 0xff;
  74                                 carry >>= 8;
  75                         }
  76
  77                         xpos += 20;
  78                 }
  79                 /* x_j = w_0|w_1 */
  80         }
  81
  82         return 0;
  83 }