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(u32 *state, const u8 data[64])
19 os_memset(&context, 0, sizeof(context));
20 context.h0 = state[0];
21 context.h1 = state[1];
22 context.h2 = state[2];
23 context.h3 = state[3];
24 context.h4 = state[4];
25 SHA1_Transform(&context, data);
26 state[0] = context.h0;
27 state[1] = context.h1;
28 state[2] = context.h2;
29 state[3] = context.h3;
30 state[4] = context.h4;
34 int fips186_2_prf(const u8 *seed, size_t seed_len, u8 *x, size_t xlen)
42 if (seed_len < sizeof(xkey))
43 os_memset(xkey + seed_len, 0, sizeof(xkey) - seed_len);
45 seed_len = sizeof(xkey);
47 /* FIPS 186-2 + change notice 1 */
49 os_memcpy(xkey, seed, seed_len);
57 for (j = 0; j < m; j++) {
59 for (i = 0; i < 2; i++) {
60 /* XVAL = (XKEY + XSEED_j) mod 2^b */
62 /* w_i = G(t, XVAL) */
64 sha1_transform(_t, xkey);
65 _t[0] = host_to_be32(_t[0]);
66 _t[1] = host_to_be32(_t[1]);
67 _t[2] = host_to_be32(_t[2]);
68 _t[3] = host_to_be32(_t[3]);
69 _t[4] = host_to_be32(_t[4]);
70 os_memcpy(xpos, _t, 20);
72 /* XKEY = (1 + XKEY + w_i) mod 2^b */
74 for (k = 19; k >= 0; k--) {
75 carry += xkey[k] + xpos[k];
76 xkey[k] = carry & 0xff;