2 * FIPS 186-2 PRF for libcrypto
3 * Copyright (c) 2004-2005, 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.
16 #include <openssl/sha.h>
22 static void sha1_transform(u8 *state, const u8 data[64])
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);
32 int fips186_2_prf(const u8 *seed, size_t seed_len, u8 *x, size_t xlen)
40 if (seed_len > sizeof(xkey))
41 seed_len = sizeof(xkey);
43 /* FIPS 186-2 + change notice 1 */
45 os_memcpy(xkey, seed, seed_len);
46 os_memset(xkey + seed_len, 0, 64 - seed_len);
54 for (j = 0; j < m; j++) {
56 for (i = 0; i < 2; i++) {
57 /* XVAL = (XKEY + XSEED_j) mod 2^b */
59 /* w_i = G(t, XVAL) */
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);
69 /* XKEY = (1 + XKEY + w_i) mod 2^b */
71 for (k = 19; k >= 0; k--) {
72 carry += xkey[k] + xpos[k];
73 xkey[k] = carry & 0xff;