88 lines
2.1 KiB
C
88 lines
2.1 KiB
C
/*
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* AES-128 CBC
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*
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* Copyright (c) 2003-2007, Jouni Malinen <j@w1.fi>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Alternatively, this software may be distributed under the terms of BSD
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* license.
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*
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* See README and COPYING for more details.
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*/
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#include "crypto/includes.h"
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#include "crypto/common.h"
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#include "crypto/aes.h"
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#include "crypto/aes_wrap.h"
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/**
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* aes_128_cbc_encrypt - AES-128 CBC encryption
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* @key: Encryption key
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* @iv: Encryption IV for CBC mode (16 bytes)
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* @data: Data to encrypt in-place
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* @data_len: Length of data in bytes (must be divisible by 16)
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* Returns: 0 on success, -1 on failure
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*/
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int
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aes_128_cbc_encrypt(const u8 *key, const u8 *iv, u8 *data, size_t data_len)
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{
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void *ctx;
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u8 cbc[AES_BLOCK_SIZE];
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u8 *pos = data;
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int i, j, blocks;
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ctx = aes_encrypt_init(key, 16);
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if (ctx == NULL)
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return -1;
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os_memcpy(cbc, iv, AES_BLOCK_SIZE);
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blocks = data_len / AES_BLOCK_SIZE;
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for (i = 0; i < blocks; i++) {
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for (j = 0; j < AES_BLOCK_SIZE; j++)
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cbc[j] ^= pos[j];
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aes_encrypt(ctx, cbc, cbc);
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os_memcpy(pos, cbc, AES_BLOCK_SIZE);
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pos += AES_BLOCK_SIZE;
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}
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aes_encrypt_deinit(ctx);
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return 0;
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}
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/**
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* aes_128_cbc_decrypt - AES-128 CBC decryption
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* @key: Decryption key
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* @iv: Decryption IV for CBC mode (16 bytes)
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* @data: Data to decrypt in-place
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* @data_len: Length of data in bytes (must be divisible by 16)
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* Returns: 0 on success, -1 on failure
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*/
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int
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aes_128_cbc_decrypt(const u8 *key, const u8 *iv, u8 *data, size_t data_len)
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{
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void *ctx;
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u8 cbc[AES_BLOCK_SIZE], tmp[AES_BLOCK_SIZE];
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u8 *pos = data;
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int i, j, blocks;
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ctx = aes_decrypt_init(key, 16);
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if (ctx == NULL)
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return -1;
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os_memcpy(cbc, iv, AES_BLOCK_SIZE);
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blocks = data_len / AES_BLOCK_SIZE;
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for (i = 0; i < blocks; i++) {
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os_memcpy(tmp, pos, AES_BLOCK_SIZE);
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aes_decrypt(ctx, pos, pos);
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for (j = 0; j < AES_BLOCK_SIZE; j++)
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pos[j] ^= cbc[j];
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os_memcpy(cbc, tmp, AES_BLOCK_SIZE);
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pos += AES_BLOCK_SIZE;
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}
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aes_decrypt_deinit(ctx);
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return 0;
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}
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