1/*
2 * AES-128/192/256 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_ctr_encrypt - AES-128/192/256 CTR mode encryption
18 * @key: Key for encryption (key_len bytes)
19 * @key_len: Length of the key (16, 24, or 32 bytes)
20 * @nonce: Nonce for counter mode (16 bytes)
21 * @data: Data to encrypt in-place
22 * @data_len: Length of data in bytes
23 * Returns: 0 on success, -1 on failure
24 */
25int aes_ctr_encrypt(const u8 *key, size_t key_len, const u8 *nonce,
26		    u8 *data, size_t data_len)
27{
28	void *ctx;
29	size_t j, len, left = data_len;
30	int i;
31	u8 *pos = data;
32	u8 counter[AES_BLOCK_SIZE], buf[AES_BLOCK_SIZE];
33
34	ctx = aes_encrypt_init(key, key_len);
35	if (ctx == NULL)
36		return -1;
37	os_memcpy(counter, nonce, AES_BLOCK_SIZE);
38
39	while (left > 0) {
40		aes_encrypt(ctx, counter, buf);
41
42		len = (left < AES_BLOCK_SIZE) ? left : AES_BLOCK_SIZE;
43		for (j = 0; j < len; j++)
44			pos[j] ^= buf[j];
45		pos += len;
46		left -= len;
47
48		for (i = AES_BLOCK_SIZE - 1; i >= 0; i--) {
49			counter[i]++;
50			if (counter[i])
51				break;
52		}
53	}
54	aes_encrypt_deinit(ctx);
55	return 0;
56}
57
58
59/**
60 * aes_128_ctr_encrypt - AES-128 CTR mode encryption
61 * @key: Key for encryption (key_len bytes)
62 * @nonce: Nonce for counter mode (16 bytes)
63 * @data: Data to encrypt in-place
64 * @data_len: Length of data in bytes
65 * Returns: 0 on success, -1 on failure
66 */
67int aes_128_ctr_encrypt(const u8 *key, const u8 *nonce,
68			u8 *data, size_t data_len)
69{
70	return aes_ctr_encrypt(key, 16, nonce, data, data_len);
71}
72