2 * FIPS 186-2 PRF for internal crypto implementation
3 * Copyright (c) 2006-2007, Jouni Malinen <j@w1.fi>
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.
9 * Alternatively, this software may be distributed under the terms of BSD
12 * See README and COPYING for more details.
21 void SHA1Transform(u32 state[5], const unsigned char buffer[64]);
24 int fips186_2_prf(const u8 *seed, size_t seed_len, u8 *x, size_t xlen)
32 if (seed_len > sizeof(xkey))
33 seed_len = sizeof(xkey);
35 /* FIPS 186-2 + change notice 1 */
37 os_memcpy(xkey, seed, seed_len);
38 os_memset(xkey + seed_len, 0, 64 - seed_len);
46 for (j = 0; j < m; j++) {
48 for (i = 0; i < 2; i++) {
49 /* XVAL = (XKEY + XSEED_j) mod 2^b */
51 /* w_i = G(t, XVAL) */
53 SHA1Transform(_t, xkey);
54 _t[0] = host_to_be32(_t[0]);
55 _t[1] = host_to_be32(_t[1]);
56 _t[2] = host_to_be32(_t[2]);
57 _t[3] = host_to_be32(_t[3]);
58 _t[4] = host_to_be32(_t[4]);
59 os_memcpy(xpos, _t, 20);
61 /* XKEY = (1 + XKEY + w_i) mod 2^b */
63 for (k = 19; k >= 0; k--) {
64 carry += xkey[k] + xpos[k];
65 xkey[k] = carry & 0xff;