void decode_block(BYTE* counter, BYTE* dst, BYTE round_key[ROUND_KEY_SIZE][BLOCK_SIZE]){
unsigned char temp[BLOCK_SIZE];
xor_key(counter,temp,round_key[ROUNDS]);
//memcpy(dst, round_key[ROUNDS], 16);
shift_rows_inv(temp,dst);
sub_bytes_inv(dst,temp);
for(int i = ROUNDS-1; i > 0; i--){
xor_key(temp, dst, round_key[i]);
mix_columns_inv(dst, temp);
shift_rows_inv(temp, dst);
sub_bytes_inv(dst, temp);
}
xor_key(temp, dst, round_key[0]);
}
void AES::test(){
BYTE src[] = {0x01, 0x02, 0x03, 0x04,
0x05, 0x06, 0x07, 0x08,
0x09, 0x10, 0x11, 0x12,
0x13, 0x14, 0x15, 0x16};
BYTE key[] = {0x05, 0x06, 0x07, 0x08,
0x01, 0x02, 0x03, 0x04,
0x09, 0x10, 0x11, 0x12,
0x13, 0x14, 0x15, 0x16};
BYTE rk[11][16];
AES::expand_key(key, rk);
BYTE dst[16];
sub_bytes_inv(src,dst);
//AES::print_state(dst);
decode_block(src, dst, rk);
/*AES::print_state(rk[0]);
AES::print_state(rk[1]);
AES::print_state(rk[2]);
AES::print_state(rk[3]);
AES::print_state(rk[4]);
AES::print_state(rk[5]);
AES::print_state(rk[6]);
AES::print_state(rk[7]);
AES::print_state(rk[8]);
AES::print_state(rk[9]);*/
AES::print_state(dst);
}
void Aes256::decrypt(unsigned char* buffer)
{
unsigned char i, rcon = 1;
copy_key();
for (i = NUM_ROUNDS / 2; i > 0; --i)
expand_enc_key(&rcon);
add_round_key(buffer, NUM_ROUNDS);
shift_rows_inv(buffer);
sub_bytes_inv(buffer);
for (i = NUM_ROUNDS, rcon = 0x80; --i;)
{
if ((i & 1))
expand_dec_key(&rcon);
add_round_key(buffer, i);
mix_columns_inv(buffer);
shift_rows_inv(buffer);
sub_bytes_inv(buffer);
}
add_round_key(buffer, i);
}
// Decrypt a single 128 bit block by a 128 bit key using AES
// http://en.wikipedia.org/wiki/Advanced_Encryption_Standard
void AES_Decrypt(unsigned char *data, unsigned char *key) {
int i; // To count the rounds
// Key expansion
unsigned char keys[176];
expand_key(key,keys);
// Reverse the final Round
xor_round_key(data,keys,10);
shift_rows_inv(data);
sub_bytes_inv(data, 16);
// Reverse the middle rounds
for (i=0; i<9; i++) {
xor_round_key(data,keys,9-i);
mix_cols_inv(data);
shift_rows_inv(data);
sub_bytes_inv(data, 16);
}
// Reverse the first Round
xor_round_key(data, keys, 0);
}
// Decrypt a single 128 bit block by a 128 bit key using AES
// http://en.wikipedia.org/wiki/Advanced_Encryption_Standard
void DecryptAES(byte *c, byte *key, byte *m) {
int i; // To count the rounds
// Key expansion
byte keys[176];
expand_key(key,keys);
// Reverse the final Round
memcpy(m,c,16);
xor_round_key(m,keys,10);
shift_rows_inv(m);
sub_bytes_inv(m, 16);
// Reverse the middle rounds
for (i=0; i<9; i++) {
xor_round_key(m,keys,9-i);
mix_cols_inv(m);
shift_rows_inv(m);
sub_bytes_inv(m, 16);
}
// Reverse the first Round
xor_round_key(m, keys, 0);
}