wpa_supplicant_node: wpa_supplicant_node: aes-cbc.c Source File

00001 /*
00002  * AES-128 CBC
00003  *
00004  * Copyright (c) 2003-2007, Jouni Malinen <j@w1.fi>
00005  *
00006  * This program is free software; you can redistribute it and/or modify
00007  * it under the terms of the GNU General Public License version 2 as
00008  * published by the Free Software Foundation.
00009  *
00010  * Alternatively, this software may be distributed under the terms of BSD
00011  * license.
00012  *
00013  * See README and COPYING for more details.
00014  */
00015 
00016 #include "includes.h"
00017 
00018 #include "common.h"
00019 #include "aes.h"
00020 #include "aes_wrap.h"
00021 
00030 int aes_128_cbc_encrypt(const u8 *key, const u8 *iv, u8 *data, size_t data_len)
00031 {
00032         void *ctx;
00033         u8 cbc[AES_BLOCK_SIZE];
00034         u8 *pos = data;
00035         int i, j, blocks;
00036 
00037         ctx = aes_encrypt_init(key, 16);
00038         if (ctx == NULL)
00039                 return -1;
00040         os_memcpy(cbc, iv, AES_BLOCK_SIZE);
00041 
00042         blocks = data_len / AES_BLOCK_SIZE;
00043         for (i = 0; i < blocks; i++) {
00044                 for (j = 0; j < AES_BLOCK_SIZE; j++)
00045                         cbc[j] ^= pos[j];
00046                 aes_encrypt(ctx, cbc, cbc);
00047                 os_memcpy(pos, cbc, AES_BLOCK_SIZE);
00048                 pos += AES_BLOCK_SIZE;
00049         }
00050         aes_encrypt_deinit(ctx);
00051         return 0;
00052 }
00053 
00054 
00063 int aes_128_cbc_decrypt(const u8 *key, const u8 *iv, u8 *data, size_t data_len)
00064 {
00065         void *ctx;
00066         u8 cbc[AES_BLOCK_SIZE], tmp[AES_BLOCK_SIZE];
00067         u8 *pos = data;
00068         int i, j, blocks;
00069 
00070         ctx = aes_decrypt_init(key, 16);
00071         if (ctx == NULL)
00072                 return -1;
00073         os_memcpy(cbc, iv, AES_BLOCK_SIZE);
00074 
00075         blocks = data_len / AES_BLOCK_SIZE;
00076         for (i = 0; i < blocks; i++) {
00077                 os_memcpy(tmp, pos, AES_BLOCK_SIZE);
00078                 aes_decrypt(ctx, pos, pos);
00079                 for (j = 0; j < AES_BLOCK_SIZE; j++)
00080                         pos[j] ^= cbc[j];
00081                 os_memcpy(cbc, tmp, AES_BLOCK_SIZE);
00082                 pos += AES_BLOCK_SIZE;
00083         }
00084         aes_decrypt_deinit(ctx);
00085         return 0;
00086 }