1/*
2 * AES-128 CBC
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_cbc_encrypt - AES-128 CBC encryption
18 * @key: Encryption key
19 * @iv: Encryption IV for CBC mode (16 bytes)
20 * @data: Data to encrypt in-place
21 * @data_len: Length of data in bytes (must be divisible by 16)
22 * Returns: 0 on success, -1 on failure
23 */
24int aes_128_cbc_encrypt(const u8 *key, const u8 *iv, u8 *data, size_t data_len)
25{
26	void *ctx;
27	u8 cbc[AES_BLOCK_SIZE];
28	u8 *pos = data;
29	int i, j, blocks;
30
31	ctx = aes_encrypt_init(key, 16);
32	if (ctx == NULL)
33		return -1;
34	os_memcpy(cbc, iv, AES_BLOCK_SIZE);
35
36	blocks = data_len / AES_BLOCK_SIZE;
37	for (i = 0; i < blocks; i++) {
38		for (j = 0; j < AES_BLOCK_SIZE; j++)
39			cbc[j] ^= pos[j];
40		aes_encrypt(ctx, cbc, cbc);
41		os_memcpy(pos, cbc, AES_BLOCK_SIZE);
42		pos += AES_BLOCK_SIZE;
43	}
44	aes_encrypt_deinit(ctx);
45	return 0;
46}
47
48
49/**
50 * aes_128_cbc_decrypt - AES-128 CBC decryption
51 * @key: Decryption key
52 * @iv: Decryption IV for CBC mode (16 bytes)
53 * @data: Data to decrypt in-place
54 * @data_len: Length of data in bytes (must be divisible by 16)
55 * Returns: 0 on success, -1 on failure
56 */
57int aes_128_cbc_decrypt(const u8 *key, const u8 *iv, u8 *data, size_t data_len)
58{
59	void *ctx;
60	u8 cbc[AES_BLOCK_SIZE], tmp[AES_BLOCK_SIZE];
61	u8 *pos = data;
62	int i, j, blocks;
63
64	ctx = aes_decrypt_init(key, 16);
65	if (ctx == NULL)
66		return -1;
67	os_memcpy(cbc, iv, AES_BLOCK_SIZE);
68
69	blocks = data_len / AES_BLOCK_SIZE;
70	for (i = 0; i < blocks; i++) {
71		os_memcpy(tmp, pos, AES_BLOCK_SIZE);
72		aes_decrypt(ctx, pos, pos);
73		for (j = 0; j < AES_BLOCK_SIZE; j++)
74			pos[j] ^= cbc[j];
75		os_memcpy(cbc, tmp, AES_BLOCK_SIZE);
76		pos += AES_BLOCK_SIZE;
77	}
78	aes_decrypt_deinit(ctx);
79	return 0;
80}
81