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| /*
| * AES Key Wrap Algorithm (RFC3394)
| *
| * Copyright (c) 2003-2007, Jouni Malinen <j@w1.fi>
| *
| * This software may be distributed under the terms of the BSD license.
| * See README 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 (RFC3394)
| * @kek: Key encryption key (KEK)
| * @kek_len: Length of KEK in octets
| * @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, size_t kek_len, int n, const u8 *plain, u8 *cipher)
| {
| u8 *a, *r, b[AES_BLOCK_SIZE];
| int i, j;
| void *ctx;
| unsigned int t;
|
| a = cipher;
| r = cipher + 8;
|
| /* 1) Initialize variables. */
| os_memset(a, 0xa6, 8);
| os_memcpy(r, plain, 8 * n);
|
| ctx = aes_encrypt_init(kek, kek_len);
| 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);
| t = n * j + i;
| a[7] ^= t;
| a[6] ^= t >> 8;
| a[5] ^= t >> 16;
| a[4] ^= t >> 24;
| 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;
| }
|
|
