workbench/network/WirelessManager/src/crypto/aes-cbc.c

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