1/*
2 * AES-128 CTR
3 *
4 * Copyright (c) 2003-2007, Jouni Malinen <j@w1.fi>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * Alternatively, this software may be distributed under the terms of BSD
11 * license.
12 *
13 * See README and COPYING for more details.
14 */
15
16#include "includes.h"
17
18#include "common.h"
19#include "aes.h"
20#include "aes_wrap.h"
21
22/**
23 * aes_128_ctr_encrypt - AES-128 CTR mode encryption
24 * @key: Key for encryption (16 bytes)
25 * @nonce: Nonce for counter mode (16 bytes)
26 * @data: Data to encrypt in-place
27 * @data_len: Length of data in bytes
28 * Returns: 0 on success, -1 on failure
29 */
30int aes_128_ctr_encrypt(const u8 *key, const u8 *nonce,
31			u8 *data, size_t data_len)
32{
33	void *ctx;
34	size_t j, len, left = data_len;
35	int i;
36	u8 *pos = data;
37	u8 counter[AES_BLOCK_SIZE], buf[AES_BLOCK_SIZE];
38
39	ctx = aes_encrypt_init(key, 16);
40	if (ctx == NULL)
41		return -1;
42	os_memcpy(counter, nonce, AES_BLOCK_SIZE);
43
44	while (left > 0) {
45		aes_encrypt(ctx, counter, buf);
46
47		len = (left < AES_BLOCK_SIZE) ? left : AES_BLOCK_SIZE;
48		for (j = 0; j < len; j++)
49			pos[j] ^= buf[j];
50		pos += len;
51		left -= len;
52
53		for (i = AES_BLOCK_SIZE - 1; i >= 0; i--) {
54			counter[i]++;
55			if (counter[i])
56				break;
57		}
58	}
59	aes_encrypt_deinit(ctx);
60	return 0;
61}
62