Home | History | Annotate | Download | only in crypto
      1 /*
      2  * AES-128 CBC
      3  *
      4  * Copyright (c) 2003-2007, Jouni Malinen <j (at) 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  */
     24 int 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 	if (TEST_FAIL())
     32 		return -1;
     33 
     34 	ctx = aes_encrypt_init(key, 16);
     35 	if (ctx == NULL)
     36 		return -1;
     37 	os_memcpy(cbc, iv, AES_BLOCK_SIZE);
     38 
     39 	blocks = data_len / AES_BLOCK_SIZE;
     40 	for (i = 0; i < blocks; i++) {
     41 		for (j = 0; j < AES_BLOCK_SIZE; j++)
     42 			cbc[j] ^= pos[j];
     43 		aes_encrypt(ctx, cbc, cbc);
     44 		os_memcpy(pos, cbc, AES_BLOCK_SIZE);
     45 		pos += AES_BLOCK_SIZE;
     46 	}
     47 	aes_encrypt_deinit(ctx);
     48 	return 0;
     49 }
     50 
     51 
     52 /**
     53  * aes_128_cbc_decrypt - AES-128 CBC decryption
     54  * @key: Decryption key
     55  * @iv: Decryption IV for CBC mode (16 bytes)
     56  * @data: Data to decrypt in-place
     57  * @data_len: Length of data in bytes (must be divisible by 16)
     58  * Returns: 0 on success, -1 on failure
     59  */
     60 int aes_128_cbc_decrypt(const u8 *key, const u8 *iv, u8 *data, size_t data_len)
     61 {
     62 	void *ctx;
     63 	u8 cbc[AES_BLOCK_SIZE], tmp[AES_BLOCK_SIZE];
     64 	u8 *pos = data;
     65 	int i, j, blocks;
     66 
     67 	if (TEST_FAIL())
     68 		return -1;
     69 
     70 	ctx = aes_decrypt_init(key, 16);
     71 	if (ctx == NULL)
     72 		return -1;
     73 	os_memcpy(cbc, iv, AES_BLOCK_SIZE);
     74 
     75 	blocks = data_len / AES_BLOCK_SIZE;
     76 	for (i = 0; i < blocks; i++) {
     77 		os_memcpy(tmp, pos, AES_BLOCK_SIZE);
     78 		aes_decrypt(ctx, pos, pos);
     79 		for (j = 0; j < AES_BLOCK_SIZE; j++)
     80 			pos[j] ^= cbc[j];
     81 		os_memcpy(cbc, tmp, AES_BLOCK_SIZE);
     82 		pos += AES_BLOCK_SIZE;
     83 	}
     84 	aes_decrypt_deinit(ctx);
     85 	return 0;
     86 }
     87