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/*
* AES Key Wrap Algorithm (128-bit KEK) (RFC3394)
*
* Copyright (c) 2003-2007, 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.h"
#include "aes_wrap.h"
/**
* aes_wrap - Wrap keys with AES Key Wrap Algorithm (128-bit KEK) (RFC3394)
* @kek: 16-octet Key encryption key (KEK)
* @n: Length of the plaintext key in 64-bit units; e.g., 2 = 128-bit = 16
* bytes
* @plain: Plaintext key to be wrapped, n * 64 bits
* @cipher: Wrapped key, (n + 1) * 64 bits
* Returns: 0 on success, -1 on failure
*/
int aes_wrap(const u8 *kek, int n, const u8 *plain, u8 *cipher)
{
u8 *a, *r, b[16];
int i, j;
void *ctx;
a = cipher;
r = cipher + 8;
/* 1) Initialize variables. */
os_memset(a, 0xa6, 8);
os_memcpy(r, plain, 8 * n);
ctx = aes_encrypt_init(kek, 16);
if (ctx == NULL)
return -1;
/* 2) Calculate intermediate values.
* For j = 0 to 5
* For i=1 to n
* B = AES(K, A | R[i])
* A = MSB(64, B) ^ t where t = (n*j)+i
* R[i] = LSB(64, B)
*/
for (j = 0; j <= 5; j++) {
r = cipher + 8;
for (i = 1; i <= n; i++) {
os_memcpy(b, a, 8);
os_memcpy(b + 8, r, 8);
aes_encrypt(ctx, b, b);
os_memcpy(a, b, 8);
a[7] ^= n * j + i;
os_memcpy(r, b + 8, 8);
r += 8;
}
}
aes_encrypt_deinit(ctx);
/* 3) Output the results.
*
* These are already in @cipher due to the location of temporary
* variables.
*/
return 0;
}
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