2 * FIPS 186-2 PRF for libcrypto
3 * Copyright (c) 2004-2005, Jouni Malinen <j@w1.fi>
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
10 #include <openssl/sha.h>
16 static void sha1_transform(u8 *state, const u8 data[64])
19 os_memset(&context, 0, sizeof(context));
20 os_memcpy(&context.h0, state, 5 * 4);
21 SHA1_Transform(&context, data);
22 os_memcpy(state, &context.h0, 5 * 4);
26 int fips186_2_prf(const u8 *seed, size_t seed_len, u8 *x, size_t xlen)
34 if (seed_len < sizeof(xkey))
35 os_memset(xkey + seed_len, 0, sizeof(xkey) - seed_len);
37 seed_len = sizeof(xkey);
39 /* FIPS 186-2 + change notice 1 */
41 os_memcpy(xkey, seed, seed_len);
49 for (j = 0; j < m; j++) {
51 for (i = 0; i < 2; i++) {
52 /* XVAL = (XKEY + XSEED_j) mod 2^b */
54 /* w_i = G(t, XVAL) */
56 sha1_transform((u8 *) _t, xkey);
57 _t[0] = host_to_be32(_t[0]);
58 _t[1] = host_to_be32(_t[1]);
59 _t[2] = host_to_be32(_t[2]);
60 _t[3] = host_to_be32(_t[3]);
61 _t[4] = host_to_be32(_t[4]);
62 os_memcpy(xpos, _t, 20);
64 /* XKEY = (1 + XKEY + w_i) mod 2^b */
66 for (k = 19; k >= 0; k--) {
67 carry += xkey[k] + xpos[k];
68 xkey[k] = carry & 0xff;