1 /* 2 * EAP server/peer: EAP-PSK shared routines 3 * Copyright (c) 2004-2006, Jouni Malinen <j (at) w1.fi> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 * 9 * Alternatively, this software may be distributed under the terms of BSD 10 * license. 11 * 12 * See README and COPYING for more details. 13 */ 14 15 #include "includes.h" 16 17 #include "common.h" 18 #include "aes_wrap.h" 19 #include "eap_defs.h" 20 #include "eap_psk_common.h" 21 22 #define aes_block_size 16 23 24 25 void eap_psk_key_setup(const u8 *psk, u8 *ak, u8 *kdk) 26 { 27 os_memset(ak, 0, aes_block_size); 28 aes_128_encrypt_block(psk, ak, ak); 29 os_memcpy(kdk, ak, aes_block_size); 30 ak[aes_block_size - 1] ^= 0x01; 31 kdk[aes_block_size - 1] ^= 0x02; 32 aes_128_encrypt_block(psk, ak, ak); 33 aes_128_encrypt_block(psk, kdk, kdk); 34 } 35 36 37 void eap_psk_derive_keys(const u8 *kdk, const u8 *rand_p, u8 *tek, u8 *msk, 38 u8 *emsk) 39 { 40 u8 hash[aes_block_size]; 41 u8 counter = 1; 42 int i; 43 44 aes_128_encrypt_block(kdk, rand_p, hash); 45 46 hash[aes_block_size - 1] ^= counter; 47 aes_128_encrypt_block(kdk, hash, tek); 48 hash[aes_block_size - 1] ^= counter; 49 counter++; 50 51 for (i = 0; i < EAP_MSK_LEN / aes_block_size; i++) { 52 hash[aes_block_size - 1] ^= counter; 53 aes_128_encrypt_block(kdk, hash, &msk[i * aes_block_size]); 54 hash[aes_block_size - 1] ^= counter; 55 counter++; 56 } 57 58 for (i = 0; i < EAP_EMSK_LEN / aes_block_size; i++) { 59 hash[aes_block_size - 1] ^= counter; 60 aes_128_encrypt_block(kdk, hash, &emsk[i * aes_block_size]); 61 hash[aes_block_size - 1] ^= counter; 62 counter++; 63 } 64 } 65
