/*
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* FIPS 186-2 PRF for internal crypto implementation
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* Copyright (c) 2006-2007, Jouni Malinen <j@w1.fi>
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*
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* This software may be distributed under the terms of the BSD license.
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* See README for more details.
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*/
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#include "includes.h"
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#include "common.h"
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#include "sha1.h"
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#include "sha1_i.h"
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#include "crypto.h"
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int fips186_2_prf(const u8 *seed, size_t seed_len, u8 *x, size_t xlen)
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{
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u8 xkey[64];
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u32 t[5], _t[5];
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int i, j, m, k;
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u8 *xpos = x;
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u32 carry;
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if (seed_len < sizeof(xkey))
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os_memset(xkey + seed_len, 0, sizeof(xkey) - seed_len);
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else
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seed_len = sizeof(xkey);
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/* FIPS 186-2 + change notice 1 */
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os_memcpy(xkey, seed, seed_len);
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t[0] = 0x67452301;
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t[1] = 0xEFCDAB89;
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t[2] = 0x98BADCFE;
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t[3] = 0x10325476;
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t[4] = 0xC3D2E1F0;
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m = xlen / 40;
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for (j = 0; j < m; j++) {
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/* XSEED_j = 0 */
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for (i = 0; i < 2; i++) {
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/* XVAL = (XKEY + XSEED_j) mod 2^b */
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/* w_i = G(t, XVAL) */
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os_memcpy(_t, t, 20);
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SHA1Transform(_t, xkey);
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_t[0] = host_to_be32(_t[0]);
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_t[1] = host_to_be32(_t[1]);
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_t[2] = host_to_be32(_t[2]);
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_t[3] = host_to_be32(_t[3]);
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_t[4] = host_to_be32(_t[4]);
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os_memcpy(xpos, _t, 20);
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/* XKEY = (1 + XKEY + w_i) mod 2^b */
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carry = 1;
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for (k = 19; k >= 0; k--) {
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carry += xkey[k] + xpos[k];
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xkey[k] = carry & 0xff;
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carry >>= 8;
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}
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xpos += SHA1_MAC_LEN;
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}
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/* x_j = w_0|w_1 */
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}
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return 0;
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}
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