1 /*
2  * AES-128 CTR
3  *
4  * Copyright (c) 2003-2007, Jouni Malinen <j@w1.fi>
5  *
6  * This software may be distributed under the terms of the BSD license.
7  * See README for more details.
8  */
9 
10 #include "includes.h"
11 
12 #include "common.h"
13 #include "aes.h"
14 #include "aes_wrap.h"
15 
16 /**
17  * aes_128_ctr_encrypt - AES-128 CTR mode encryption
18  * @key: Key for encryption (16 bytes)
19  * @nonce: Nonce for counter mode (16 bytes)
20  * @data: Data to encrypt in-place
21  * @data_len: Length of data in bytes
22  * Returns: 0 on success, -1 on failure
23  */
24 int aes_128_ctr_encrypt(const u8 *key, const u8 *nonce,
25 			u8 *data, size_t data_len)
26 {
27 	void *ctx;
28 	size_t j, len, left = data_len;
29 	int i;
30 	u8 *pos = data;
31 	u8 counter[AES_BLOCK_SIZE], buf[AES_BLOCK_SIZE];
32 
33 	ctx = aes_encrypt_init(key, 16);
34 	if (ctx == NULL)
35 		return -1;
36 	os_memcpy(counter, nonce, AES_BLOCK_SIZE);
37 
38 	while (left > 0) {
39 		aes_encrypt(ctx, counter, buf);
40 
41 		len = (left < AES_BLOCK_SIZE) ? left : AES_BLOCK_SIZE;
42 		for (j = 0; j < len; j++)
43 			pos[j] ^= buf[j];
44 		pos += len;
45 		left -= len;
46 
47 		for (i = AES_BLOCK_SIZE - 1; i >= 0; i--) {
48 			counter[i]++;
49 			if (counter[i])
50 				break;
51 		}
52 	}
53 	aes_encrypt_deinit(ctx);
54 	return 0;
55 }
56