2 * FIPS 186-2 PRF for libcrypto
3 * Copyright (c) 2004-2017, 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 <wolfssl/options.h>
11 #include <wolfssl/wolfcrypt/sha.h>
17 static void sha1_transform(u32 *state, const u8 data[64])
21 os_memset(&sha, 0, sizeof(sha));
22 sha.digest[0] = state[0];
23 sha.digest[1] = state[1];
24 sha.digest[2] = state[2];
25 sha.digest[3] = state[3];
26 sha.digest[4] = state[4];
27 wc_ShaUpdate(&sha, data, 64);
28 state[0] = sha.digest[0];
29 state[1] = sha.digest[1];
30 state[2] = sha.digest[2];
31 state[3] = sha.digest[3];
32 state[4] = sha.digest[4];
36 int fips186_2_prf(const u8 *seed, size_t seed_len, u8 *x, size_t xlen)
44 if (seed_len < sizeof(xkey))
45 os_memset(xkey + seed_len, 0, sizeof(xkey) - seed_len);
47 seed_len = sizeof(xkey);
49 /* FIPS 186-2 + change notice 1 */
51 os_memcpy(xkey, seed, seed_len);
59 for (j = 0; j < m; j++) {
61 for (i = 0; i < 2; i++) {
62 /* XVAL = (XKEY + XSEED_j) mod 2^b */
64 /* w_i = G(t, XVAL) */
66 sha1_transform(_t, xkey);
67 WPA_PUT_BE32(xpos, _t[0]);
68 WPA_PUT_BE32(xpos + 4, _t[1]);
69 WPA_PUT_BE32(xpos + 8, _t[2]);
70 WPA_PUT_BE32(xpos + 12, _t[3]);
71 WPA_PUT_BE32(xpos + 16, _t[4]);
73 /* XKEY = (1 + XKEY + w_i) mod 2^b */
75 for (k = 19; k >= 0; k--) {
76 carry += xkey[k] + xpos[k];
77 xkey[k] = carry & 0xff;