1 /*
2 * FIPS 186-2 PRF for libcrypto
3 * Copyright (c) 2004-2005, Jouni Malinen <j@w1.fi>
4 *
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
7 */
8
9 #include "includes.h"
10 #include <openssl/sha.h>
11
12 #include "common.h"
13 #include "crypto.h"
14
15
sha1_transform(u32 * state,const u8 data[64])16 static void sha1_transform(u32 *state, const u8 data[64])
17 {
18 SHA_CTX context;
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;
31 }
32
33
fips186_2_prf(const u8 * seed,size_t seed_len,u8 * x,size_t xlen)34 int fips186_2_prf(const u8 *seed, size_t seed_len, u8 *x, size_t xlen)
35 {
36 u8 xkey[64];
37 u32 t[5], _t[5];
38 int i, j, m, k;
39 u8 *xpos = x;
40 u32 carry;
41
42 if (seed_len < sizeof(xkey))
43 os_memset(xkey + seed_len, 0, sizeof(xkey) - seed_len);
44 else
45 seed_len = sizeof(xkey);
46
47 /* FIPS 186-2 + change notice 1 */
48
49 os_memcpy(xkey, seed, seed_len);
50 t[0] = 0x67452301;
51 t[1] = 0xEFCDAB89;
52 t[2] = 0x98BADCFE;
53 t[3] = 0x10325476;
54 t[4] = 0xC3D2E1F0;
55
56 m = xlen / 40;
57 for (j = 0; j < m; j++) {
58 /* XSEED_j = 0 */
59 for (i = 0; i < 2; i++) {
60 /* XVAL = (XKEY + XSEED_j) mod 2^b */
61
62 /* w_i = G(t, XVAL) */
63 os_memcpy(_t, t, 20);
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);
71
72 /* XKEY = (1 + XKEY + w_i) mod 2^b */
73 carry = 1;
74 for (k = 19; k >= 0; k--) {
75 carry += xkey[k] + xpos[k];
76 xkey[k] = carry & 0xff;
77 carry >>= 8;
78 }
79
80 xpos += 20;
81 }
82 /* x_j = w_0|w_1 */
83 }
84
85 return 0;
86 }
87