1*3ff40c12SJohn Marino /*
2*3ff40c12SJohn Marino * FIPS 186-2 PRF for internal crypto implementation
3*3ff40c12SJohn Marino * Copyright (c) 2006-2007, Jouni Malinen <j@w1.fi>
4*3ff40c12SJohn Marino *
5*3ff40c12SJohn Marino * This software may be distributed under the terms of the BSD license.
6*3ff40c12SJohn Marino * See README for more details.
7*3ff40c12SJohn Marino */
8*3ff40c12SJohn Marino
9*3ff40c12SJohn Marino #include "includes.h"
10*3ff40c12SJohn Marino
11*3ff40c12SJohn Marino #include "common.h"
12*3ff40c12SJohn Marino #include "sha1.h"
13*3ff40c12SJohn Marino #include "sha1_i.h"
14*3ff40c12SJohn Marino #include "crypto.h"
15*3ff40c12SJohn Marino
16*3ff40c12SJohn Marino
fips186_2_prf(const u8 * seed,size_t seed_len,u8 * x,size_t xlen)17*3ff40c12SJohn Marino int fips186_2_prf(const u8 *seed, size_t seed_len, u8 *x, size_t xlen)
18*3ff40c12SJohn Marino {
19*3ff40c12SJohn Marino u8 xkey[64];
20*3ff40c12SJohn Marino u32 t[5], _t[5];
21*3ff40c12SJohn Marino int i, j, m, k;
22*3ff40c12SJohn Marino u8 *xpos = x;
23*3ff40c12SJohn Marino u32 carry;
24*3ff40c12SJohn Marino
25*3ff40c12SJohn Marino if (seed_len < sizeof(xkey))
26*3ff40c12SJohn Marino os_memset(xkey + seed_len, 0, sizeof(xkey) - seed_len);
27*3ff40c12SJohn Marino else
28*3ff40c12SJohn Marino seed_len = sizeof(xkey);
29*3ff40c12SJohn Marino
30*3ff40c12SJohn Marino /* FIPS 186-2 + change notice 1 */
31*3ff40c12SJohn Marino
32*3ff40c12SJohn Marino os_memcpy(xkey, seed, seed_len);
33*3ff40c12SJohn Marino t[0] = 0x67452301;
34*3ff40c12SJohn Marino t[1] = 0xEFCDAB89;
35*3ff40c12SJohn Marino t[2] = 0x98BADCFE;
36*3ff40c12SJohn Marino t[3] = 0x10325476;
37*3ff40c12SJohn Marino t[4] = 0xC3D2E1F0;
38*3ff40c12SJohn Marino
39*3ff40c12SJohn Marino m = xlen / 40;
40*3ff40c12SJohn Marino for (j = 0; j < m; j++) {
41*3ff40c12SJohn Marino /* XSEED_j = 0 */
42*3ff40c12SJohn Marino for (i = 0; i < 2; i++) {
43*3ff40c12SJohn Marino /* XVAL = (XKEY + XSEED_j) mod 2^b */
44*3ff40c12SJohn Marino
45*3ff40c12SJohn Marino /* w_i = G(t, XVAL) */
46*3ff40c12SJohn Marino os_memcpy(_t, t, 20);
47*3ff40c12SJohn Marino SHA1Transform(_t, xkey);
48*3ff40c12SJohn Marino _t[0] = host_to_be32(_t[0]);
49*3ff40c12SJohn Marino _t[1] = host_to_be32(_t[1]);
50*3ff40c12SJohn Marino _t[2] = host_to_be32(_t[2]);
51*3ff40c12SJohn Marino _t[3] = host_to_be32(_t[3]);
52*3ff40c12SJohn Marino _t[4] = host_to_be32(_t[4]);
53*3ff40c12SJohn Marino os_memcpy(xpos, _t, 20);
54*3ff40c12SJohn Marino
55*3ff40c12SJohn Marino /* XKEY = (1 + XKEY + w_i) mod 2^b */
56*3ff40c12SJohn Marino carry = 1;
57*3ff40c12SJohn Marino for (k = 19; k >= 0; k--) {
58*3ff40c12SJohn Marino carry += xkey[k] + xpos[k];
59*3ff40c12SJohn Marino xkey[k] = carry & 0xff;
60*3ff40c12SJohn Marino carry >>= 8;
61*3ff40c12SJohn Marino }
62*3ff40c12SJohn Marino
63*3ff40c12SJohn Marino xpos += SHA1_MAC_LEN;
64*3ff40c12SJohn Marino }
65*3ff40c12SJohn Marino /* x_j = w_0|w_1 */
66*3ff40c12SJohn Marino }
67*3ff40c12SJohn Marino
68*3ff40c12SJohn Marino return 0;
69*3ff40c12SJohn Marino }
70