private static byte[] s_func(byte[] ina)
{
ina = Feistel.separateBytes(ina, 6);
byte[] outa = new byte[ina.Length / 2];
int halfByte = 0;
unchecked
{
for (int b = 0; b < ina.Length; b++)
{
byte valByte = ina[b];
int r = 2 * (valByte >> 7 & 0x0001) + (valByte >> 2 & 0x0001);
int c = valByte >> 3 & 0x000F;
int val = sboxes[b, r, c];
if (b % 2 == 0)
{
halfByte = val;
}
else
{
outa[b / 2] = (byte)(16 * halfByte + val);
}
}
}
return(outa);
}
public static byte[] decrypt(byte[] input, byte[] K1)
{
byte[] key_des = Feistel.form_des_key(K1);
byte[][] K = Feistel.generateSubKeys(key_des);
byte[] dec = Feistel.encrypt64Bloc(input, K, true);
return(dec);
}
private static byte[] encrypt64Bloc(byte[] bloc, byte[][] subkeys, bool isDecrypt)
{
byte[] R = new byte[4];
byte[] L = new byte[4];
//tmp = Feistel.permutFunc(bloc, IP);
L = Utilities.extractBits(bloc, 0, 32);
R = Utilities.extractBits(bloc, 32, 32);
for (int i = 0; i < 4; i++)
{
byte[] tmpR = R;
if (isDecrypt)
{
R = Feistel.f_func(R, subkeys[3 - i]);
}
else
{
R = Feistel.f_func(R, subkeys[i]);
}
R = Utilities.xor(L, R);
L = tmpR;
}
bloc = Utilities.concatBits(R, 32, L, 32);
// tmp = Feistel.permutFunc(tmp, invIP);
return(bloc);
}
public static byte[] encrypt(byte[] input, byte[] K1)
{
//HttpContext.Current.Trace.Warn("Feistel.encrypt K1 = " + System.Text.Encoding.UTF8.GetString(K1));
byte[] key_des = Feistel.form_des_key(K1);
byte[][] K = Feistel.generateSubKeys(key_des);
byte[] enc = Feistel.encrypt64Bloc(input, K, false);
return(enc);
}
private static byte[] f_func(byte[] R, byte[] K)
{
byte[] tmp;
tmp = Feistel.permutFunc(R, expandTbl);
tmp = Utilities.xor(tmp, K);
tmp = Feistel.s_func(tmp);
tmp = Feistel.permutFunc(tmp, P);
return(tmp);
}
private static byte[][] generateSubKeys(byte[] key)
{
byte[][] tmp = new byte[16][];
byte[] tmpK = Feistel.permutFunc(key, PC1);
byte[] C = Utilities.extractBits(tmpK, 0, PC1.Length / 2);
byte[] D = Utilities.extractBits(tmpK, PC1.Length / 2, PC1.Length / 2);
for (int i = 0; i < 16; i++)
{
C = Feistel.rotLeft(C, 28, keyShift[i]);
D = Feistel.rotLeft(D, 28, keyShift[i]);
byte[] cd = Utilities.concatBits(C, 28, D, 28);
tmp[i] = Feistel.permutFunc(cd, PC2);
}
return(tmp);
}
private static byte[] decryptBloc(byte[] ina, byte[] key_array)
{
byte[] tmp = new byte[ina.Length];
byte[] tmp1 = new byte[ina.Length / 2];
byte[] tmp2 = new byte[ina.Length / 2];
// 2D State Array Declaration
byte[][] state = new byte[4][];
int j = 0;
while (j < 4)
{
state[j] = new byte[Nb];
j++;
}
//Form 2D Array of State
for (int i = 0; i < ina.Length; i++)
{
state[i / 4][i % 4] = ina[i % 4 * 4 + i / 4];
}
//Last Round Decrypted
state = AESFeistel.AddRoundKey(state, w, Nr);
state = AESFeistel.InvShiftRows(state);
state = AESFeistel.InvSubBytes(state);
//Rounds 6 to 9 Decrypted
for (int round = Nr - 1; round >= 6; round--)
{
state = AESFeistel.AddRoundKey(state, w, round);
state = AESFeistel.InvMixColumns(state);
state = AESFeistel.InvShiftRows(state);
state = AESFeistel.InvSubBytes(state);
}
//Convert Back to 1D Array
for (int i = 0; i < tmp.Length; i++)
{
tmp[i % 4 * 4 + i / 4] = state[i / 4][i % 4];
}
tmp1 = Utilities.extractBits(tmp, 0, 64);
tmp2 = Utilities.extractBits(tmp, 64, 64);
//FEISTEL CIPHER
tmp1 = Feistel.decrypt(tmp1, key_array);
tmp2 = Feistel.decrypt(tmp2, key_array);
//Join 2 arrays
tmp = Utilities.concatBits(tmp2, 64, tmp1, 64);
//Covert back to 2D Array for further AES rounds
for (int i = 0; i < tmp.Length; i++)
{
state[i / 4][i % 4] = tmp[i % 4 * 4 + i / 4];
}
//Rounds 1 to 5 Decrypted
for (int round = 5; round >= 1; round--)
{
state = AESFeistel.AddRoundKey(state, w, round);
state = AESFeistel.InvMixColumns(state);
state = AESFeistel.InvShiftRows(state);
state = AESFeistel.InvSubBytes(state);
}
//Initial Round Decryption
state = AESFeistel.AddRoundKey(state, w, 0);
//Convert back to 1D Array
for (int i = 0; i < tmp.Length; i++)
{
tmp[i % 4 * 4 + i / 4] = state[i / 4][i % 4];
}
return(tmp);
}