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git.ipfire.org Git - thirdparty/hostap.git/blob - src/crypto/aes-wrap.c
2 * AES Key Wrap Algorithm (RFC3394)
4 * Copyright (c) 2003-2007, Jouni Malinen <j@w1.fi>
6 * This software may be distributed under the terms of the BSD license.
7 * See README for more details.
17 * aes_wrap - Wrap keys with AES Key Wrap Algorithm (RFC3394)
18 * @kek: Key encryption key (KEK)
19 * @kek_len: Length of KEK in octets
20 * @n: Length of the plaintext key in 64-bit units; e.g., 2 = 128-bit = 16
22 * @plain: Plaintext key to be wrapped, n * 64 bits
23 * @cipher: Wrapped key, (n + 1) * 64 bits
24 * Returns: 0 on success, -1 on failure
26 int aes_wrap(const u8
*kek
, size_t kek_len
, int n
, const u8
*plain
, u8
*cipher
)
28 u8
*a
, *r
, b
[AES_BLOCK_SIZE
];
35 /* 1) Initialize variables. */
36 os_memset(a
, 0xa6, 8);
37 os_memcpy(r
, plain
, 8 * n
);
39 ctx
= aes_encrypt_init(kek
, kek_len
);
43 /* 2) Calculate intermediate values.
46 * B = AES(K, A | R[i])
47 * A = MSB(64, B) ^ t where t = (n*j)+i
50 for (j
= 0; j
<= 5; j
++) {
52 for (i
= 1; i
<= n
; i
++) {
54 os_memcpy(b
+ 8, r
, 8);
55 aes_encrypt(ctx
, b
, b
);
58 os_memcpy(r
, b
+ 8, 8);
62 aes_encrypt_deinit(ctx
);
64 /* 3) Output the results.
66 * These are already in @cipher due to the location of temporary