2 * One-key CBC MAC (OMAC1) hash with AES
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.
16 static void gf_mulx(u8 *pad)
20 carry = pad[0] & 0x80;
21 for (i = 0; i < AES_BLOCK_SIZE - 1; i++)
22 pad[i] = (pad[i] << 1) | (pad[i + 1] >> 7);
23 pad[AES_BLOCK_SIZE - 1] <<= 1;
25 pad[AES_BLOCK_SIZE - 1] ^= 0x87;
30 * omac1_aes_vector - One-Key CBC MAC (OMAC1) hash with AES
31 * @key: Key for the hash operation
32 * @key_len: Key length in octets
33 * @num_elem: Number of elements in the data vector
34 * @addr: Pointers to the data areas
35 * @len: Lengths of the data blocks
36 * @mac: Buffer for MAC (128 bits, i.e., 16 bytes)
37 * Returns: 0 on success, -1 on failure
39 * This is a mode for using block cipher (AES in this case) for authentication.
40 * OMAC1 was standardized with the name CMAC by NIST in a Special Publication
43 int omac1_aes_vector(const u8 *key, size_t key_len, size_t num_elem,
44 const u8 *addr[], const size_t *len, u8 *mac)
47 u8 cbc[AES_BLOCK_SIZE], pad[AES_BLOCK_SIZE];
49 size_t i, e, left, total_len;
54 ctx = aes_encrypt_init(key, key_len);
57 os_memset(cbc, 0, AES_BLOCK_SIZE);
60 for (e = 0; e < num_elem; e++)
68 while (left >= AES_BLOCK_SIZE) {
69 for (i = 0; i < AES_BLOCK_SIZE; i++) {
73 * Stop if there are no more bytes to process
74 * since there are no more entries in the array.
76 if (i + 1 == AES_BLOCK_SIZE &&
77 left == AES_BLOCK_SIZE)
84 if (left > AES_BLOCK_SIZE)
85 aes_encrypt(ctx, cbc, cbc);
86 left -= AES_BLOCK_SIZE;
89 os_memset(pad, 0, AES_BLOCK_SIZE);
90 aes_encrypt(ctx, pad, pad);
93 if (left || total_len == 0) {
94 for (i = 0; i < left; i++) {
98 * Stop if there are no more bytes to process
99 * since there are no more entries in the array.
112 for (i = 0; i < AES_BLOCK_SIZE; i++)
114 aes_encrypt(ctx, pad, mac);
115 aes_encrypt_deinit(ctx);
121 * omac1_aes_128_vector - One-Key CBC MAC (OMAC1) hash with AES-128
122 * @key: 128-bit key for the hash operation
123 * @num_elem: Number of elements in the data vector
124 * @addr: Pointers to the data areas
125 * @len: Lengths of the data blocks
126 * @mac: Buffer for MAC (128 bits, i.e., 16 bytes)
127 * Returns: 0 on success, -1 on failure
129 * This is a mode for using block cipher (AES in this case) for authentication.
130 * OMAC1 was standardized with the name CMAC by NIST in a Special Publication
133 int omac1_aes_128_vector(const u8 *key, size_t num_elem,
134 const u8 *addr[], const size_t *len, u8 *mac)
136 return omac1_aes_vector(key, 16, num_elem, addr, len, mac);
141 * omac1_aes_128 - One-Key CBC MAC (OMAC1) hash with AES-128 (aka AES-CMAC)
142 * @key: 128-bit key for the hash operation
143 * @data: Data buffer for which a MAC is determined
144 * @data_len: Length of data buffer in bytes
145 * @mac: Buffer for MAC (128 bits, i.e., 16 bytes)
146 * Returns: 0 on success, -1 on failure
148 * This is a mode for using block cipher (AES in this case) for authentication.
149 * OMAC1 was standardized with the name CMAC by NIST in a Special Publication
152 int omac1_aes_128(const u8 *key, const u8 *data, size_t data_len, u8 *mac)
154 return omac1_aes_128_vector(key, 1, &data, &data_len, mac);
159 * omac1_aes_256 - One-Key CBC MAC (OMAC1) hash with AES-256 (aka AES-CMAC)
160 * @key: 256-bit key for the hash operation
161 * @data: Data buffer for which a MAC is determined
162 * @data_len: Length of data buffer in bytes
163 * @mac: Buffer for MAC (128 bits, i.e., 16 bytes)
164 * Returns: 0 on success, -1 on failure
166 * This is a mode for using block cipher (AES in this case) for authentication.
167 * OMAC1 was standardized with the name CMAC by NIST in a Special Publication
170 int omac1_aes_256(const u8 *key, const u8 *data, size_t data_len, u8 *mac)
172 return omac1_aes_vector(key, 32, 1, &data, &data_len, mac);