1214501Srpaulo/* 2214501Srpaulo * FIPS 186-2 PRF for internal crypto implementation 3214501Srpaulo * Copyright (c) 2006-2007, Jouni Malinen <j@w1.fi> 4214501Srpaulo * 5252726Srpaulo * This software may be distributed under the terms of the BSD license. 6252726Srpaulo * See README for more details. 7214501Srpaulo */ 8214501Srpaulo 9214501Srpaulo#include "includes.h" 10214501Srpaulo 11214501Srpaulo#include "common.h" 12214501Srpaulo#include "sha1.h" 13214501Srpaulo#include "sha1_i.h" 14214501Srpaulo#include "crypto.h" 15214501Srpaulo 16214501Srpaulo 17214501Srpauloint fips186_2_prf(const u8 *seed, size_t seed_len, u8 *x, size_t xlen) 18214501Srpaulo{ 19214501Srpaulo u8 xkey[64]; 20214501Srpaulo u32 t[5], _t[5]; 21214501Srpaulo int i, j, m, k; 22214501Srpaulo u8 *xpos = x; 23214501Srpaulo u32 carry; 24214501Srpaulo 25252726Srpaulo if (seed_len < sizeof(xkey)) 26252726Srpaulo os_memset(xkey + seed_len, 0, sizeof(xkey) - seed_len); 27252726Srpaulo else 28214501Srpaulo seed_len = sizeof(xkey); 29214501Srpaulo 30214501Srpaulo /* FIPS 186-2 + change notice 1 */ 31214501Srpaulo 32214501Srpaulo os_memcpy(xkey, seed, seed_len); 33214501Srpaulo t[0] = 0x67452301; 34214501Srpaulo t[1] = 0xEFCDAB89; 35214501Srpaulo t[2] = 0x98BADCFE; 36214501Srpaulo t[3] = 0x10325476; 37214501Srpaulo t[4] = 0xC3D2E1F0; 38214501Srpaulo 39214501Srpaulo m = xlen / 40; 40214501Srpaulo for (j = 0; j < m; j++) { 41214501Srpaulo /* XSEED_j = 0 */ 42214501Srpaulo for (i = 0; i < 2; i++) { 43214501Srpaulo /* XVAL = (XKEY + XSEED_j) mod 2^b */ 44214501Srpaulo 45214501Srpaulo /* w_i = G(t, XVAL) */ 46214501Srpaulo os_memcpy(_t, t, 20); 47214501Srpaulo SHA1Transform(_t, xkey); 48214501Srpaulo _t[0] = host_to_be32(_t[0]); 49214501Srpaulo _t[1] = host_to_be32(_t[1]); 50214501Srpaulo _t[2] = host_to_be32(_t[2]); 51214501Srpaulo _t[3] = host_to_be32(_t[3]); 52214501Srpaulo _t[4] = host_to_be32(_t[4]); 53214501Srpaulo os_memcpy(xpos, _t, 20); 54214501Srpaulo 55214501Srpaulo /* XKEY = (1 + XKEY + w_i) mod 2^b */ 56214501Srpaulo carry = 1; 57214501Srpaulo for (k = 19; k >= 0; k--) { 58214501Srpaulo carry += xkey[k] + xpos[k]; 59214501Srpaulo xkey[k] = carry & 0xff; 60214501Srpaulo carry >>= 8; 61214501Srpaulo } 62214501Srpaulo 63214501Srpaulo xpos += SHA1_MAC_LEN; 64214501Srpaulo } 65214501Srpaulo /* x_j = w_0|w_1 */ 66214501Srpaulo } 67214501Srpaulo 68214501Srpaulo return 0; 69214501Srpaulo} 70