public static byte[] encrypt(byte[] ina, byte[] key)
{
Nb = 4;
Nk = 4;
Nr = Nk + 6;
initiv();
int pad_len = 0;
byte[] padding = new byte[1];
int i;
pad_len = 16 - ina.Length % 16;
padding = new byte[pad_len];
padding[0] = (byte)0x80;
for (i = 1; i < pad_len; i++)
{
padding[i] = 0;
}
byte[] tmp = new byte[ina.Length + pad_len];
byte[] bloc = new byte[16];
w = generateSubkeys(key);
int count = 0;
for (i = 0; i < ina.Length + pad_len; i++)
{
if (i > 0 && i % 16 == 0)
{
bloc = Utilities.xor(bloc, iv);
bloc = AESFeistel.encryptBloc(bloc, key);
iv = Utilities.extractBits(bloc, 0, 128);
Array.Copy(bloc, 0, tmp, i - 16, bloc.Length);
}
if (i < ina.Length)
{
bloc[i % 16] = ina[i];
}
else
{
bloc[i % 16] = padding[count % 16];
count++;
}
}
if (bloc.Length == 16)
{
bloc = Utilities.xor(bloc, iv);
bloc = AESFeistel.encryptBloc(bloc, key);
iv = Utilities.extractBits(bloc, 0, 128);
Array.Copy(bloc, 0, tmp, i - 16, bloc.Length);
}
return(tmp);
}
//encrypted filename: orig_filename.encrypted
//returns RSA encrypted key for sharing
public static string encrypt(string inp_filepath, string rsa_public_key_xml)
{
//inp_filepath = System.Web.Hosting.HostingEnvironment.MapPath(inp_filepath);
//converting to absolute path
string filename = Path.GetFileName(inp_filepath);
string enc_filepath = "~/f2_encrypted/encrypted_" + filename;
//converting to absolute path
enc_filepath = System.Web.Hosting.HostingEnvironment.MapPath(enc_filepath);
string af_key = System.Guid.NewGuid().ToString();
byte[] af_key_bytes = Encoding.ASCII.GetBytes(af_key);
byte[] inp_file = File.ReadAllBytes(inp_filepath);
byte[] enc_file = AESFeistel.encrypt(inp_file, af_key_bytes);
HttpContext.Current.Trace.Warn("Output file = " + enc_filepath);
File.WriteAllBytes(enc_filepath, enc_file);
string enc_af_key = RSA.encrypt(af_key, rsa_public_key_xml);
return(enc_af_key);
}
private static byte[][] generateSubkeys(byte[] key)
{
byte[][] tmp = new byte[Nb * (Nr + 1)][];
int i = 0;
while (i < Nk)
{
tmp[i] = new byte[4];
i++;
}
i = 0;
while (i < Nk)
{
tmp[i][0] = key[i * 4];
tmp[i][1] = key[i * 4 + 1];
tmp[i][2] = key[i * 4 + 2];
tmp[i][3] = key[i * 4 + 3];
i++;
}
i = Nk;
while (i < Nb * (Nr + 1))
{
byte[] temp = new byte[4];
for (int k = 0; k < 4; k++)
{
temp[k] = tmp[i - 1][k];
}
if (i % Nk == 0)
{
temp = AESFeistel.SubWord(AESFeistel.rotateWord(temp));
temp[0] = (byte)(temp[0] ^ (Rcon[i / Nk] & 0xff));
}
else if (Nk > 6 && i % Nk == 4)
{
temp = AESFeistel.SubWord(temp);
}
tmp[i] = Utilities.xor(tmp[i - Nk], temp);
i++;
}
return(tmp);
}
private static byte[][] MixColumns(byte[][] s)
{
int[] sp = new int[4];
byte b02 = (byte)0x02,
b03 = (byte)0x03;
for (int c = 0; c < 4; c++)
{
sp[0] = AESFeistel.FFMul(b02, s[0][c]) ^ AESFeistel.FFMul(b03, s[1][c]) ^ s[2][c] ^ s[3][c];
sp[1] = s[0][c] ^ AESFeistel.FFMul(b02, s[1][c]) ^ AESFeistel.FFMul(b03, s[2][c]) ^ s[3][c];
sp[2] = s[0][c] ^ s[1][c] ^ AESFeistel.FFMul(b02, s[2][c]) ^ AESFeistel.FFMul(b03, s[3][c]);
sp[3] = AESFeistel.FFMul(b03, s[0][c]) ^ s[1][c] ^ s[2][c] ^ AESFeistel.FFMul(b02, s[3][c]);
for (int i = 0; i < 4; i++)
{
s[i][c] = (byte)(sp[i]);
}
}
return(s);
}
public static byte[] decrypt(byte[] ina, byte[] key)
{
int i;
byte[] tmp = new byte[ina.Length];
byte[] bloc = new byte[16];
initiv();
Nb = 4;
Nk = 4;
Nr = Nk + 6;
w = generateSubkeys(key);
for (i = 0; i < ina.Length; i++)
{
if (i > 0 && i % 16 == 0)
{
temp = Utilities.extractBits(bloc, 0, 128);
bloc = AESFeistel.decryptBloc(bloc, key);
bloc = Utilities.xor(bloc, iv);
iv = Utilities.extractBits(temp, 0, 128);
Array.Copy(bloc, 0, tmp, i - 16, bloc.Length);
}
if (i < ina.Length)
{
bloc[i % 16] = ina[i];
}
}
temp = Utilities.extractBits(bloc, 0, 128);
bloc = AESFeistel.decryptBloc(bloc, key);
bloc = Utilities.xor(bloc, iv);
iv = Utilities.extractBits(temp, 0, 128);
Array.Copy(bloc, 0, tmp, i - 16, bloc.Length);
tmp = deletePadding(tmp);
return(tmp);
}
private static byte[][] InvMixColumns(byte[][] s)
{
int[] sp = new int[4];
byte b02 = (byte)0x0e,
b03 = (byte)0x0b,
b04 = (byte)0x0d,
b05 = (byte)0x09;
for (int c = 0; c < 4; c++)
{
sp[0] = AESFeistel.FFMul(b02, s[0][c]) ^ AESFeistel.FFMul(b03, s[1][c]) ^ AESFeistel.FFMul(b04, s[2][c]) ^ AESFeistel.FFMul(b05, s[3][c]);
sp[1] = AESFeistel.FFMul(b05, s[0][c]) ^ AESFeistel.FFMul(b02, s[1][c]) ^ AESFeistel.FFMul(b03, s[2][c]) ^ AESFeistel.FFMul(b04, s[3][c]);
sp[2] = AESFeistel.FFMul(b04, s[0][c]) ^ AESFeistel.FFMul(b05, s[1][c]) ^ AESFeistel.FFMul(b02, s[2][c]) ^ AESFeistel.FFMul(b03, s[3][c]);
sp[3] = AESFeistel.FFMul(b03, s[0][c]) ^ AESFeistel.FFMul(b04, s[1][c]) ^ AESFeistel.FFMul(b05, s[2][c]) ^ AESFeistel.FFMul(b02, s[3][c]);
for (int i = 0; i < 4; i++)
{
s[i][c] = (byte)(sp[i]);
}
}
return(s);
}
//outputs decrypted filepath
public static string decrypt(string enc_filepath, string enc_af_key, string rsa_private_key_xml)
{
//converting to absolute path
//enc_filepath = System.Web.Hosting.HostingEnvironment.MapPath(enc_filepath);
string filenameNoExt = Path.GetFileName(enc_filepath); //removes .enc
string dec_filepath = "~/f4_decrypted/" + filenameNoExt;
//converting to absolute path
dec_filepath = System.Web.Hosting.HostingEnvironment.MapPath(dec_filepath);
string af_key = RSA.decrypt(enc_af_key, rsa_private_key_xml);
byte[] af_key_bytes = Encoding.ASCII.GetBytes(af_key);
byte[] enc_file = File.ReadAllBytes(enc_filepath);
byte[] dec_file = AESFeistel.decrypt(enc_file, af_key_bytes);
File.WriteAllBytes(dec_filepath, dec_file);
return("~/f4_decrypted/" + filenameNoExt);
}
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);
}
