/* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
*
* Libhashkit library
*
* Copyright (C) 2012 Data Differential, http://datadifferential.com/
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
*
* * The names of its contributors may not be used to endorse or
* promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include "libhashkit/common.h"
#include "libhashkit/rijndael.hpp"
#include <cstring>
#define AES_KEY_LENGTH 256 /* 128, 192, 256 */
#define AES_BLOCK_SIZE 16
enum encrypt_t
{
AES_ENCRYPT,
AES_DECRYPT
};
struct _key_t {
int nr;
uint32_t rk[4*(AES_MAXNR +1)];
};
struct aes_key_t {
_key_t encode_key;
_key_t decode_key;
};
aes_key_t* aes_create_key(const char *key, const size_t key_length)
{
aes_key_t* _aes_key= (aes_key_t*)(calloc(1, sizeof(aes_key_t)));
if (_aes_key)
{
uint8_t rkey[AES_KEY_LENGTH/8];
uint8_t *rkey_end= rkey +AES_KEY_LENGTH/8;
const char *key_end= key +key_length;
memset(rkey, 0, sizeof(rkey)); /* Set initial key */
uint8_t *ptr= rkey;
const char* sptr= key;
for (; sptr < key_end; ptr++,sptr++)
{
if (ptr == rkey_end)
{
ptr= rkey; /* Just loop over tmp_key until we used all key */
}
*ptr^= (uint8_t)(*sptr);
}
_aes_key->decode_key.nr= rijndaelKeySetupDec(_aes_key->decode_key.rk, rkey, AES_KEY_LENGTH);
_aes_key->encode_key.nr= rijndaelKeySetupEnc(_aes_key->encode_key.rk, rkey, AES_KEY_LENGTH);
}
return _aes_key;
}
aes_key_t* aes_clone_key(aes_key_t *_aes_key)
{
if (_aes_key == NULL)
{
return NULL;
}
aes_key_t* _aes_clone_key= (aes_key_t*)(calloc(1, sizeof(aes_key_t)));
if (_aes_clone_key)
{
memcpy(_aes_clone_key, _aes_key, sizeof(aes_key_t));
}
return _aes_clone_key;
}
hashkit_string_st* aes_encrypt(aes_key_t *_aes_key,
const char* source, size_t source_length)
{
if (_aes_key == NULL)
{
return NULL;
}
size_t num_blocks= source_length/AES_BLOCK_SIZE;
hashkit_string_st* destination= hashkit_string_create(source_length);
if (destination)
{
char *dest= hashkit_string_c_str_mutable(destination);
for (size_t x= num_blocks; x > 0; x--) /* Encode complete blocks */
{
rijndaelEncrypt(_aes_key->encode_key.rk, _aes_key->encode_key.nr, (const uint8_t*)(source),
(uint8_t*) (dest));
source+= AES_BLOCK_SIZE;
dest+= AES_BLOCK_SIZE;
}
uint8_t block[AES_BLOCK_SIZE];
char pad_len= AES_BLOCK_SIZE - (source_length - AES_BLOCK_SIZE*num_blocks);
memcpy(block, source, 16 -pad_len);
memset(block + AES_BLOCK_SIZE -pad_len, pad_len, pad_len);
rijndaelEncrypt(_aes_key->encode_key.rk, _aes_key->encode_key.nr, block, (uint8_t*) (dest));
hashkit_string_set_length(destination, AES_BLOCK_SIZE*(num_blocks + 1));
}
return destination;
}
hashkit_string_st* aes_decrypt(aes_key_t *_aes_key,
const char* source, size_t source_length)
{
if (_aes_key == NULL)
{
return NULL;
}
size_t num_blocks= source_length/AES_BLOCK_SIZE;
if ((source_length != num_blocks*AES_BLOCK_SIZE) or num_blocks ==0 )
{
return NULL;
}
hashkit_string_st* destination= hashkit_string_create(source_length);
if (destination)
{
char *dest= hashkit_string_c_str_mutable(destination);
for (size_t x = num_blocks-1; x > 0; x--)
{
rijndaelDecrypt(_aes_key->decode_key.rk, _aes_key->decode_key.nr, (const uint8_t*) (source), (uint8_t*)(dest));
source+= AES_BLOCK_SIZE;
dest+= AES_BLOCK_SIZE;
}
uint8_t block[AES_BLOCK_SIZE];
rijndaelDecrypt(_aes_key->decode_key.rk, _aes_key->decode_key.nr, (const uint8_t*)(source), block);
/* Use last char in the block as size */
unsigned int pad_len= (unsigned int) (unsigned char)(block[AES_BLOCK_SIZE-1]);
if (pad_len > AES_BLOCK_SIZE)
{
hashkit_string_free(destination);
return NULL;
}
/* We could also check whole padding but we do not really need this */
memcpy(dest, block, AES_BLOCK_SIZE - pad_len);
hashkit_string_set_length(destination, AES_BLOCK_SIZE*num_blocks - pad_len);
}
return destination;
}