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/*
* EAP server/peer: EAP-PSK shared routines
* Copyright (c) 2004-2006, Jouni Malinen <j@w1.fi>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Alternatively, this software may be distributed under the terms of BSD
* license.
*
* See README and COPYING for more details.
*/
#include "includes.h"
#include "common.h"
#include "aes_wrap.h"
#include "eap_defs.h"
#include "eap_psk_common.h"
#define aes_block_size 16
void eap_psk_key_setup(const u8 *psk, u8 *ak, u8 *kdk)
{
os_memset(ak, 0, aes_block_size);
aes_128_encrypt_block(psk, ak, ak);
os_memcpy(kdk, ak, aes_block_size);
ak[aes_block_size - 1] ^= 0x01;
kdk[aes_block_size - 1] ^= 0x02;
aes_128_encrypt_block(psk, ak, ak);
aes_128_encrypt_block(psk, kdk, kdk);
}
void eap_psk_derive_keys(const u8 *kdk, const u8 *rand_p, u8 *tek, u8 *msk,
u8 *emsk)
{
u8 hash[aes_block_size];
u8 counter = 1;
int i;
aes_128_encrypt_block(kdk, rand_p, hash);
hash[aes_block_size - 1] ^= counter;
aes_128_encrypt_block(kdk, hash, tek);
hash[aes_block_size - 1] ^= counter;
counter++;
for (i = 0; i < EAP_MSK_LEN / aes_block_size; i++) {
hash[aes_block_size - 1] ^= counter;
aes_128_encrypt_block(kdk, hash, &msk[i * aes_block_size]);
hash[aes_block_size - 1] ^= counter;
counter++;
}
for (i = 0; i < EAP_EMSK_LEN / aes_block_size; i++) {
hash[aes_block_size - 1] ^= counter;
aes_128_encrypt_block(kdk, hash, &emsk[i * aes_block_size]);
hash[aes_block_size - 1] ^= counter;
counter++;
}
}
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