2014-01-06 22:45:30 +00:00

141 lines
4.1 KiB
C++

/*
* libretroshare/src/utils: rsaes.cc
*
* AES crptography for RetroShare.
*
* Copyright 2013 by Cyril Soler
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License Version 2 as published by the Free Software Foundation.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA.
*
* Please report all bugs and problems to "csoler@users.sourceforge.net".
*
*/
#include <iostream>
#include <openssl/evp.h>
#include <openssl/aes.h>
#include "rsaes.h"
uint32_t RsAES::get_buffer_size(uint32_t n)
{
return n + AES_BLOCK_SIZE ;
}
bool RsAES::aes_crypt_8_16(const uint8_t *input_data,uint32_t input_data_length,uint8_t key_data[16],uint8_t salt[8],uint8_t *output_data,uint32_t& output_data_length)
{
int nrounds = 5;
uint8_t key[32], iv[32];
/*
* Gen key & IV for AES 256 CBC mode. A SHA1 digest is used to hash the supplied key material.
* nrounds is the number of times the we hash the material. More rounds are more secure but
* slower.
*/
int i = EVP_BytesToKey(EVP_aes_256_cbc(), EVP_sha1(), salt, key_data, 16, nrounds, key, iv);
if (i != 32)
{
printf("Key size is %d bits - should be 256 bits\n", i);
return false ;
}
EVP_CIPHER_CTX e_ctx ;
EVP_CIPHER_CTX_init(&e_ctx);
EVP_EncryptInit_ex(&e_ctx, EVP_aes_256_cbc(), NULL, key, iv);
/* max ciphertext len for a n bytes of plaintext is n + AES_BLOCK_SIZE -1 bytes */
int c_len = input_data_length + AES_BLOCK_SIZE ;
int f_len = 0;
if(output_data_length < (uint32_t)c_len)
return false ;
/* update ciphertext, c_len is filled with the length of ciphertext generated,
*len is the size of plaintext in bytes */
if(!EVP_EncryptUpdate(&e_ctx, output_data, &c_len, input_data, input_data_length))
{
std::cerr << "RsAES: decryption failed at end. Check padding." << std::endl;
return false ;
}
/* update ciphertext with the final remaining bytes */
if(!EVP_EncryptFinal_ex(&e_ctx, output_data+c_len, &f_len))
{
std::cerr << "RsAES: decryption failed at end. Check padding." << std::endl;
return false ;
}
output_data_length = c_len + f_len;
EVP_CIPHER_CTX_cleanup(&e_ctx) ;
return true;
}
bool RsAES::aes_decrypt_8_16(const uint8_t *input_data,uint32_t input_data_length,uint8_t key_data[16],uint8_t salt[8],uint8_t *output_data,uint32_t& output_data_length)
{
int nrounds = 5;
uint8_t key[32], iv[32];
/*
* Gen key & IV for AES 256 CBC mode. A SHA1 digest is used to hash the supplied key material.
* nrounds is the number of times the we hash the material. More rounds are more secure but
* slower.
*/
int i = EVP_BytesToKey(EVP_aes_256_cbc(), EVP_sha1(), salt, key_data, 16, nrounds, key, iv);
if (i != 32)
{
printf("Key size is %d bits - should be 256 bits\n", i);
return false ;
}
EVP_CIPHER_CTX e_ctx ;
EVP_CIPHER_CTX_init(&e_ctx);
EVP_DecryptInit_ex(&e_ctx, EVP_aes_256_cbc(), NULL, key, iv);
/* max ciphertext len for a n bytes of plaintext is n + AES_BLOCK_SIZE -1 bytes */
int c_len = input_data_length + AES_BLOCK_SIZE ;
int f_len = 0;
if(output_data_length < (uint32_t)c_len)
return false ;
output_data_length = c_len ;
/* update ciphertext, c_len is filled with the length of ciphertext generated,
*len is the size of plaintext in bytes */
if(! EVP_DecryptUpdate(&e_ctx, output_data, &c_len, input_data, input_data_length))
{
std::cerr << "RsAES: decryption failed." << std::endl;
return false ;
}
/* update ciphertext with the final remaining bytes */
if(!EVP_DecryptFinal_ex(&e_ctx, output_data+c_len, &f_len))
{
std::cerr << "RsAES: decryption failed at end. Check padding." << std::endl;
return false ;
}
output_data_length = c_len + f_len;
EVP_CIPHER_CTX_cleanup(&e_ctx) ;
return true;
}