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/* Copyright (C) 2002 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/*
Implementation of AES Encryption for MySQL
Initial version by Peter Zaitsev June 2002
*/
#include "my_global.h"
#include "m_string.h"
#include "my_aes.h"
enum encrypt_dir { AES_ENCRYPT, AES_DECRYPT };
#define AES_BLOCK_SIZE 16
/* Block size in bytes */
#define AES_BAD_DATA -1
/* If bad data discovered during decoding */
/* The structure for key information */
typedef struct {
int nr; /* Number of rounds */
uint32 rk[4*(MAXNR + 1)]; /* key schedule */
} KEYINSTANCE;
/*
This is internal function just keeps joint code of Key generation
rkey - Address of Key Instance to be created
direction - Direction (are we encoding or decoding)
key - key to use for real key creation
key_length - length of the key
returns - returns 0 on success and negative on error
*/
static int my_aes_create_key(KEYINSTANCE* aes_key,char direction, char* key,
int key_length)
{
char rkey[AES_KEY_LENGTH/8]; /* The real key to be used for encryption */
char *ptr; /* Start of the real key*/
char *rkey_end=rkey+AES_KEY_LENGTH/8; /* Real key boundary */
char *sptr; /* Start of the working key */
char *key_end=key+key_length; /* Working key boundary*/
bzero(rkey,AES_KEY_LENGTH/8); /* Set initial key */
for (ptr= rkey, sptr= key; sptr < key_end; ptr++,sptr++)
{
if (ptr == rkey_end)
ptr= rkey; /* Just loop over tmp_key until we used all key */
*ptr^= *sptr;
}
if (direction==AES_DECRYPT)
aes_key->nr = rijndaelKeySetupDec(aes_key->rk, rkey, AES_KEY_LENGTH);
else
aes_key->nr = rijndaelKeySetupEnc(aes_key->rk, rkey, AES_KEY_LENGTH);
return 0;
}
/*
my_aes_encrypt - Crypt buffer with AES encryption algorithm.
source - Pinter to data for encryption
source_length - size of encruption data
dest - buffer to place encrypted data (must be large enough)
key - Key to be used for encryption
kel_length - Lenght of the key. Will handle keys of any length
returns - size of encrypted data, or negative in case of error.
*/
int my_aes_encrypt(const char* source, int source_length, const char* dest,
const char* key, int key_length)
{
KEYINSTANCE aes_key;
char block[AES_BLOCK_SIZE]; /* 128 bit block used for padding */
int rc; /* result codes */
int num_blocks; /* number of complete blocks */
char pad_len; /* pad size for the last block */
int i;
if ((rc=my_aes_create_key(&aes_key,AES_ENCRYPT,key,key_length)))
return rc;
num_blocks = source_length/AES_BLOCK_SIZE;
for (i = num_blocks; i > 0; i--) /* Encode complete blocks */
{
rijndaelEncrypt(aes_key.rk, aes_key.nr, source, dest);
source+= AES_BLOCK_SIZE;
dest+= AES_BLOCK_SIZE;
}
/* Encode the rest. We always have incomplete block */
pad_len = AES_BLOCK_SIZE - (source_length - AES_BLOCK_SIZE*num_blocks);
memcpy(block, source, 16 - pad_len);
bfill(block + AES_BLOCK_SIZE - pad_len, pad_len, pad_len);
rijndaelEncrypt(aes_key.rk, aes_key.nr, block, dest);
return AES_BLOCK_SIZE*(num_blocks + 1);
}
/*
my_aes_decrypt - DeCrypt buffer with AES encryption algorithm.
source - Pinter to data for decryption
source_length - size of encrypted data
dest - buffer to place decrypted data (must be large enough)
key - Key to be used for decryption
kel_length - Lenght of the key. Will handle keys of any length
returns - size of original data, or negative in case of error.
*/
int my_aes_decrypt(const char* source, int source_length, const char* dest,
const char* key, int key_length)
{
KEYINSTANCE aes_key;
char block[AES_BLOCK_SIZE]; /* 128 bit block used for padding */
int rc; /* result codes */
int num_blocks; /* number of complete blocks */
char pad_len; /* pad size for the last block */
int i;
if ((rc=my_aes_create_key(&aes_key,AES_DECRYPT,key,key_length)))
return rc;
num_blocks = source_length/AES_BLOCK_SIZE;
if ( (source_length!=num_blocks*AES_BLOCK_SIZE) || num_blocks==0)
return AES_BAD_DATA; /* Input size has to be even and at leas one block */
for (i = num_blocks-1; i > 0; i--) /* Decode all but last blocks */
{
rijndaelDecrypt(aes_key.rk, aes_key.nr, source, dest);
source+= AES_BLOCK_SIZE;
dest+= AES_BLOCK_SIZE;
}
rijndaelDecrypt(aes_key.rk, aes_key.nr, source, block);
pad_len = block[AES_BLOCK_SIZE-1]; /* Just use last char in the block as size*/
if (pad_len > AES_BLOCK_SIZE)
return AES_BAD_DATA;
/* We could also check whole padding but we do not really need this */
memcpy(dest, block, AES_BLOCK_SIZE - pad_len);
return AES_BLOCK_SIZE*num_blocks - pad_len;
}
/*
my_aes_get_size - get size of buffer which will be large enough for encrypted
data
source_length - length of data to be encrypted
returns - size of buffer required to store encrypted data
*/
int my_aes_get_size(int source_length)
{
return AES_BLOCK_SIZE*(source_length/AES_BLOCK_SIZE)+AES_BLOCK_SIZE;
}
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