diff --git a/crypto/src/crypto/engines/TwofishEngine.cs b/crypto/src/crypto/engines/TwofishEngine.cs
new file mode 100644
index 000000000..b983d9d31
--- /dev/null
+++ b/crypto/src/crypto/engines/TwofishEngine.cs
@@ -0,0 +1,675 @@
+using System;
+
+using Org.BouncyCastle.Crypto.Parameters;
+
+namespace Org.BouncyCastle.Crypto.Engines
+{
+ /**
+ * A class that provides Twofish encryption operations.
+ *
+ * This Java implementation is based on the Java reference
+ * implementation provided by Bruce Schneier and developed
+ * by Raif S. Naffah.
+ */
+ public sealed class TwofishEngine
+ : IBlockCipher
+ {
+ private static readonly byte[,] P = {
+ { // p0
+ (byte) 0xA9, (byte) 0x67, (byte) 0xB3, (byte) 0xE8,
+ (byte) 0x04, (byte) 0xFD, (byte) 0xA3, (byte) 0x76,
+ (byte) 0x9A, (byte) 0x92, (byte) 0x80, (byte) 0x78,
+ (byte) 0xE4, (byte) 0xDD, (byte) 0xD1, (byte) 0x38,
+ (byte) 0x0D, (byte) 0xC6, (byte) 0x35, (byte) 0x98,
+ (byte) 0x18, (byte) 0xF7, (byte) 0xEC, (byte) 0x6C,
+ (byte) 0x43, (byte) 0x75, (byte) 0x37, (byte) 0x26,
+ (byte) 0xFA, (byte) 0x13, (byte) 0x94, (byte) 0x48,
+ (byte) 0xF2, (byte) 0xD0, (byte) 0x8B, (byte) 0x30,
+ (byte) 0x84, (byte) 0x54, (byte) 0xDF, (byte) 0x23,
+ (byte) 0x19, (byte) 0x5B, (byte) 0x3D, (byte) 0x59,
+ (byte) 0xF3, (byte) 0xAE, (byte) 0xA2, (byte) 0x82,
+ (byte) 0x63, (byte) 0x01, (byte) 0x83, (byte) 0x2E,
+ (byte) 0xD9, (byte) 0x51, (byte) 0x9B, (byte) 0x7C,
+ (byte) 0xA6, (byte) 0xEB, (byte) 0xA5, (byte) 0xBE,
+ (byte) 0x16, (byte) 0x0C, (byte) 0xE3, (byte) 0x61,
+ (byte) 0xC0, (byte) 0x8C, (byte) 0x3A, (byte) 0xF5,
+ (byte) 0x73, (byte) 0x2C, (byte) 0x25, (byte) 0x0B,
+ (byte) 0xBB, (byte) 0x4E, (byte) 0x89, (byte) 0x6B,
+ (byte) 0x53, (byte) 0x6A, (byte) 0xB4, (byte) 0xF1,
+ (byte) 0xE1, (byte) 0xE6, (byte) 0xBD, (byte) 0x45,
+ (byte) 0xE2, (byte) 0xF4, (byte) 0xB6, (byte) 0x66,
+ (byte) 0xCC, (byte) 0x95, (byte) 0x03, (byte) 0x56,
+ (byte) 0xD4, (byte) 0x1C, (byte) 0x1E, (byte) 0xD7,
+ (byte) 0xFB, (byte) 0xC3, (byte) 0x8E, (byte) 0xB5,
+ (byte) 0xE9, (byte) 0xCF, (byte) 0xBF, (byte) 0xBA,
+ (byte) 0xEA, (byte) 0x77, (byte) 0x39, (byte) 0xAF,
+ (byte) 0x33, (byte) 0xC9, (byte) 0x62, (byte) 0x71,
+ (byte) 0x81, (byte) 0x79, (byte) 0x09, (byte) 0xAD,
+ (byte) 0x24, (byte) 0xCD, (byte) 0xF9, (byte) 0xD8,
+ (byte) 0xE5, (byte) 0xC5, (byte) 0xB9, (byte) 0x4D,
+ (byte) 0x44, (byte) 0x08, (byte) 0x86, (byte) 0xE7,
+ (byte) 0xA1, (byte) 0x1D, (byte) 0xAA, (byte) 0xED,
+ (byte) 0x06, (byte) 0x70, (byte) 0xB2, (byte) 0xD2,
+ (byte) 0x41, (byte) 0x7B, (byte) 0xA0, (byte) 0x11,
+ (byte) 0x31, (byte) 0xC2, (byte) 0x27, (byte) 0x90,
+ (byte) 0x20, (byte) 0xF6, (byte) 0x60, (byte) 0xFF,
+ (byte) 0x96, (byte) 0x5C, (byte) 0xB1, (byte) 0xAB,
+ (byte) 0x9E, (byte) 0x9C, (byte) 0x52, (byte) 0x1B,
+ (byte) 0x5F, (byte) 0x93, (byte) 0x0A, (byte) 0xEF,
+ (byte) 0x91, (byte) 0x85, (byte) 0x49, (byte) 0xEE,
+ (byte) 0x2D, (byte) 0x4F, (byte) 0x8F, (byte) 0x3B,
+ (byte) 0x47, (byte) 0x87, (byte) 0x6D, (byte) 0x46,
+ (byte) 0xD6, (byte) 0x3E, (byte) 0x69, (byte) 0x64,
+ (byte) 0x2A, (byte) 0xCE, (byte) 0xCB, (byte) 0x2F,
+ (byte) 0xFC, (byte) 0x97, (byte) 0x05, (byte) 0x7A,
+ (byte) 0xAC, (byte) 0x7F, (byte) 0xD5, (byte) 0x1A,
+ (byte) 0x4B, (byte) 0x0E, (byte) 0xA7, (byte) 0x5A,
+ (byte) 0x28, (byte) 0x14, (byte) 0x3F, (byte) 0x29,
+ (byte) 0x88, (byte) 0x3C, (byte) 0x4C, (byte) 0x02,
+ (byte) 0xB8, (byte) 0xDA, (byte) 0xB0, (byte) 0x17,
+ (byte) 0x55, (byte) 0x1F, (byte) 0x8A, (byte) 0x7D,
+ (byte) 0x57, (byte) 0xC7, (byte) 0x8D, (byte) 0x74,
+ (byte) 0xB7, (byte) 0xC4, (byte) 0x9F, (byte) 0x72,
+ (byte) 0x7E, (byte) 0x15, (byte) 0x22, (byte) 0x12,
+ (byte) 0x58, (byte) 0x07, (byte) 0x99, (byte) 0x34,
+ (byte) 0x6E, (byte) 0x50, (byte) 0xDE, (byte) 0x68,
+ (byte) 0x65, (byte) 0xBC, (byte) 0xDB, (byte) 0xF8,
+ (byte) 0xC8, (byte) 0xA8, (byte) 0x2B, (byte) 0x40,
+ (byte) 0xDC, (byte) 0xFE, (byte) 0x32, (byte) 0xA4,
+ (byte) 0xCA, (byte) 0x10, (byte) 0x21, (byte) 0xF0,
+ (byte) 0xD3, (byte) 0x5D, (byte) 0x0F, (byte) 0x00,
+ (byte) 0x6F, (byte) 0x9D, (byte) 0x36, (byte) 0x42,
+ (byte) 0x4A, (byte) 0x5E, (byte) 0xC1, (byte) 0xE0 },
+ { // p1
+ (byte) 0x75, (byte) 0xF3, (byte) 0xC6, (byte) 0xF4,
+ (byte) 0xDB, (byte) 0x7B, (byte) 0xFB, (byte) 0xC8,
+ (byte) 0x4A, (byte) 0xD3, (byte) 0xE6, (byte) 0x6B,
+ (byte) 0x45, (byte) 0x7D, (byte) 0xE8, (byte) 0x4B,
+ (byte) 0xD6, (byte) 0x32, (byte) 0xD8, (byte) 0xFD,
+ (byte) 0x37, (byte) 0x71, (byte) 0xF1, (byte) 0xE1,
+ (byte) 0x30, (byte) 0x0F, (byte) 0xF8, (byte) 0x1B,
+ (byte) 0x87, (byte) 0xFA, (byte) 0x06, (byte) 0x3F,
+ (byte) 0x5E, (byte) 0xBA, (byte) 0xAE, (byte) 0x5B,
+ (byte) 0x8A, (byte) 0x00, (byte) 0xBC, (byte) 0x9D,
+ (byte) 0x6D, (byte) 0xC1, (byte) 0xB1, (byte) 0x0E,
+ (byte) 0x80, (byte) 0x5D, (byte) 0xD2, (byte) 0xD5,
+ (byte) 0xA0, (byte) 0x84, (byte) 0x07, (byte) 0x14,
+ (byte) 0xB5, (byte) 0x90, (byte) 0x2C, (byte) 0xA3,
+ (byte) 0xB2, (byte) 0x73, (byte) 0x4C, (byte) 0x54,
+ (byte) 0x92, (byte) 0x74, (byte) 0x36, (byte) 0x51,
+ (byte) 0x38, (byte) 0xB0, (byte) 0xBD, (byte) 0x5A,
+ (byte) 0xFC, (byte) 0x60, (byte) 0x62, (byte) 0x96,
+ (byte) 0x6C, (byte) 0x42, (byte) 0xF7, (byte) 0x10,
+ (byte) 0x7C, (byte) 0x28, (byte) 0x27, (byte) 0x8C,
+ (byte) 0x13, (byte) 0x95, (byte) 0x9C, (byte) 0xC7,
+ (byte) 0x24, (byte) 0x46, (byte) 0x3B, (byte) 0x70,
+ (byte) 0xCA, (byte) 0xE3, (byte) 0x85, (byte) 0xCB,
+ (byte) 0x11, (byte) 0xD0, (byte) 0x93, (byte) 0xB8,
+ (byte) 0xA6, (byte) 0x83, (byte) 0x20, (byte) 0xFF,
+ (byte) 0x9F, (byte) 0x77, (byte) 0xC3, (byte) 0xCC,
+ (byte) 0x03, (byte) 0x6F, (byte) 0x08, (byte) 0xBF,
+ (byte) 0x40, (byte) 0xE7, (byte) 0x2B, (byte) 0xE2,
+ (byte) 0x79, (byte) 0x0C, (byte) 0xAA, (byte) 0x82,
+ (byte) 0x41, (byte) 0x3A, (byte) 0xEA, (byte) 0xB9,
+ (byte) 0xE4, (byte) 0x9A, (byte) 0xA4, (byte) 0x97,
+ (byte) 0x7E, (byte) 0xDA, (byte) 0x7A, (byte) 0x17,
+ (byte) 0x66, (byte) 0x94, (byte) 0xA1, (byte) 0x1D,
+ (byte) 0x3D, (byte) 0xF0, (byte) 0xDE, (byte) 0xB3,
+ (byte) 0x0B, (byte) 0x72, (byte) 0xA7, (byte) 0x1C,
+ (byte) 0xEF, (byte) 0xD1, (byte) 0x53, (byte) 0x3E,
+ (byte) 0x8F, (byte) 0x33, (byte) 0x26, (byte) 0x5F,
+ (byte) 0xEC, (byte) 0x76, (byte) 0x2A, (byte) 0x49,
+ (byte) 0x81, (byte) 0x88, (byte) 0xEE, (byte) 0x21,
+ (byte) 0xC4, (byte) 0x1A, (byte) 0xEB, (byte) 0xD9,
+ (byte) 0xC5, (byte) 0x39, (byte) 0x99, (byte) 0xCD,
+ (byte) 0xAD, (byte) 0x31, (byte) 0x8B, (byte) 0x01,
+ (byte) 0x18, (byte) 0x23, (byte) 0xDD, (byte) 0x1F,
+ (byte) 0x4E, (byte) 0x2D, (byte) 0xF9, (byte) 0x48,
+ (byte) 0x4F, (byte) 0xF2, (byte) 0x65, (byte) 0x8E,
+ (byte) 0x78, (byte) 0x5C, (byte) 0x58, (byte) 0x19,
+ (byte) 0x8D, (byte) 0xE5, (byte) 0x98, (byte) 0x57,
+ (byte) 0x67, (byte) 0x7F, (byte) 0x05, (byte) 0x64,
+ (byte) 0xAF, (byte) 0x63, (byte) 0xB6, (byte) 0xFE,
+ (byte) 0xF5, (byte) 0xB7, (byte) 0x3C, (byte) 0xA5,
+ (byte) 0xCE, (byte) 0xE9, (byte) 0x68, (byte) 0x44,
+ (byte) 0xE0, (byte) 0x4D, (byte) 0x43, (byte) 0x69,
+ (byte) 0x29, (byte) 0x2E, (byte) 0xAC, (byte) 0x15,
+ (byte) 0x59, (byte) 0xA8, (byte) 0x0A, (byte) 0x9E,
+ (byte) 0x6E, (byte) 0x47, (byte) 0xDF, (byte) 0x34,
+ (byte) 0x35, (byte) 0x6A, (byte) 0xCF, (byte) 0xDC,
+ (byte) 0x22, (byte) 0xC9, (byte) 0xC0, (byte) 0x9B,
+ (byte) 0x89, (byte) 0xD4, (byte) 0xED, (byte) 0xAB,
+ (byte) 0x12, (byte) 0xA2, (byte) 0x0D, (byte) 0x52,
+ (byte) 0xBB, (byte) 0x02, (byte) 0x2F, (byte) 0xA9,
+ (byte) 0xD7, (byte) 0x61, (byte) 0x1E, (byte) 0xB4,
+ (byte) 0x50, (byte) 0x04, (byte) 0xF6, (byte) 0xC2,
+ (byte) 0x16, (byte) 0x25, (byte) 0x86, (byte) 0x56,
+ (byte) 0x55, (byte) 0x09, (byte) 0xBE, (byte) 0x91 }
+ };
+
+ /**
+ * Define the fixed p0/p1 permutations used in keyed S-box lookup.
+ * By changing the following constant definitions, the S-boxes will
+ * automatically Get changed in the Twofish engine.
+ */
+ private const int P_00 = 1;
+ private const int P_01 = 0;
+ private const int P_02 = 0;
+ private const int P_03 = P_01 ^ 1;
+ private const int P_04 = 1;
+
+ private const int P_10 = 0;
+ private const int P_11 = 0;
+ private const int P_12 = 1;
+ private const int P_13 = P_11 ^ 1;
+ private const int P_14 = 0;
+
+ private const int P_20 = 1;
+ private const int P_21 = 1;
+ private const int P_22 = 0;
+ private const int P_23 = P_21 ^ 1;
+ private const int P_24 = 0;
+
+ private const int P_30 = 0;
+ private const int P_31 = 1;
+ private const int P_32 = 1;
+ private const int P_33 = P_31 ^ 1;
+ private const int P_34 = 1;
+
+ /* Primitive polynomial for GF(256) */
+ private const int GF256_FDBK = 0x169;
+ private const int GF256_FDBK_2 = GF256_FDBK / 2;
+ private const int GF256_FDBK_4 = GF256_FDBK / 4;
+
+ private const int RS_GF_FDBK = 0x14D; // field generator
+
+ //====================================
+ // Useful constants
+ //====================================
+
+ private const int ROUNDS = 16;
+ private const int MAX_ROUNDS = 16; // bytes = 128 bits
+ private const int BLOCK_SIZE = 16; // bytes = 128 bits
+ private const int MAX_KEY_BITS = 256;
+
+ private const int INPUT_WHITEN=0;
+ private const int OUTPUT_WHITEN=INPUT_WHITEN+BLOCK_SIZE/4; // 4
+ private const int ROUND_SUBKEYS=OUTPUT_WHITEN+BLOCK_SIZE/4;// 8
+
+ private const int TOTAL_SUBKEYS=ROUND_SUBKEYS+2*MAX_ROUNDS;// 40
+
+ private const int SK_STEP = 0x02020202;
+ private const int SK_BUMP = 0x01010101;
+ private const int SK_ROTL = 9;
+
+ private bool encrypting;
+
+ private int[] gMDS0 = new int[MAX_KEY_BITS];
+ private int[] gMDS1 = new int[MAX_KEY_BITS];
+ private int[] gMDS2 = new int[MAX_KEY_BITS];
+ private int[] gMDS3 = new int[MAX_KEY_BITS];
+
+ /**
+ * gSubKeys[] and gSBox[] are eventually used in the
+ * encryption and decryption methods.
+ */
+ private int[] gSubKeys;
+ private int[] gSBox;
+
+ private int k64Cnt;
+
+ private byte[] workingKey;
+
+ public TwofishEngine()
+ {
+ // calculate the MDS matrix
+ int[] m1 = new int[2];
+ int[] mX = new int[2];
+ int[] mY = new int[2];
+ int j;
+
+ for (int i=0; i< MAX_KEY_BITS ; i++)
+ {
+ j = P[0,i] & 0xff;
+ m1[0] = j;
+ mX[0] = Mx_X(j) & 0xff;
+ mY[0] = Mx_Y(j) & 0xff;
+
+ j = P[1,i] & 0xff;
+ m1[1] = j;
+ mX[1] = Mx_X(j) & 0xff;
+ mY[1] = Mx_Y(j) & 0xff;
+
+ gMDS0[i] = m1[P_00] | mX[P_00] << 8 |
+ mY[P_00] << 16 | mY[P_00] << 24;
+
+ gMDS1[i] = mY[P_10] | mY[P_10] << 8 |
+ mX[P_10] << 16 | m1[P_10] << 24;
+
+ gMDS2[i] = mX[P_20] | mY[P_20] << 8 |
+ m1[P_20] << 16 | mY[P_20] << 24;
+
+ gMDS3[i] = mX[P_30] | m1[P_30] << 8 |
+ mY[P_30] << 16 | mX[P_30] << 24;
+ }
+ }
+
+ /**
+ * initialise a Twofish cipher.
+ *
+ * @param forEncryption whether or not we are for encryption.
+ * @param parameters the parameters required to set up the cipher.
+ * @exception ArgumentException if the parameters argument is
+ * inappropriate.
+ */
+ public void Init(
+ bool forEncryption,
+ ICipherParameters parameters)
+ {
+ if (!(parameters is KeyParameter))
+ throw new ArgumentException("invalid parameter passed to Twofish init - " + parameters.GetType().ToString());
+
+ this.encrypting = forEncryption;
+ this.workingKey = ((KeyParameter)parameters).GetKey();
+ this.k64Cnt = (this.workingKey.Length / 8); // pre-padded ?
+ SetKey(this.workingKey);
+ }
+
+ public string AlgorithmName
+ {
+ get { return "Twofish"; }
+ }
+
+ public bool IsPartialBlockOkay
+ {
+ get { return false; }
+ }
+
+ public int ProcessBlock(
+ byte[] input,
+ int inOff,
+ byte[] output,
+ int outOff)
+ {
+ if (workingKey == null)
+ throw new InvalidOperationException("Twofish not initialised");
+ if ((inOff + BLOCK_SIZE) > input.Length)
+ throw new DataLengthException("input buffer too short");
+ if ((outOff + BLOCK_SIZE) > output.Length)
+ throw new DataLengthException("output buffer too short");
+
+ if (encrypting)
+ {
+ EncryptBlock(input, inOff, output, outOff);
+ }
+ else
+ {
+ DecryptBlock(input, inOff, output, outOff);
+ }
+
+ return BLOCK_SIZE;
+ }
+
+ public void Reset()
+ {
+ if (this.workingKey != null)
+ {
+ SetKey(this.workingKey);
+ }
+ }
+
+ public int GetBlockSize()
+ {
+ return BLOCK_SIZE;
+ }
+
+ //==================================
+ // Private Implementation
+ //==================================
+
+ private void SetKey(byte[] key)
+ {
+ int[] k32e = new int[MAX_KEY_BITS/64]; // 4
+ int[] k32o = new int[MAX_KEY_BITS/64]; // 4
+
+ int[] sBoxKeys = new int[MAX_KEY_BITS/64]; // 4
+ gSubKeys = new int[TOTAL_SUBKEYS];
+
+ if (k64Cnt < 1)
+ {
+ throw new ArgumentException("Key size less than 64 bits");
+ }
+
+ if (k64Cnt > 4)
+ {
+ throw new ArgumentException("Key size larger than 256 bits");
+ }
+
+ /*
+ * k64Cnt is the number of 8 byte blocks (64 chunks)
+ * that are in the input key. The input key is a
+ * maximum of 32 bytes ( 256 bits ), so the range
+ * for k64Cnt is 1..4
+ */
+ for (int i=0,p=0; i<k64Cnt ; i++)
+ {
+ p = i* 8;
+
+ k32e[i] = BytesTo32Bits(key, p);
+ k32o[i] = BytesTo32Bits(key, p+4);
+
+ sBoxKeys[k64Cnt-1-i] = RS_MDS_Encode(k32e[i], k32o[i]);
+ }
+
+ int q,A,B;
+ for (int i=0; i < TOTAL_SUBKEYS / 2 ; i++)
+ {
+ q = i*SK_STEP;
+ A = F32(q, k32e);
+ B = F32(q+SK_BUMP, k32o);
+ B = B << 8 | (int)((uint)B >> 24);
+ A += B;
+ gSubKeys[i*2] = A;
+ A += B;
+ gSubKeys[i*2 + 1] = A << SK_ROTL | (int)((uint)A >> (32-SK_ROTL));
+ }
+
+ /*
+ * fully expand the table for speed
+ */
+ int k0 = sBoxKeys[0];
+ int k1 = sBoxKeys[1];
+ int k2 = sBoxKeys[2];
+ int k3 = sBoxKeys[3];
+ int b0, b1, b2, b3;
+ gSBox = new int[4*MAX_KEY_BITS];
+ for (int i=0; i<MAX_KEY_BITS; i++)
+ {
+ b0 = b1 = b2 = b3 = i;
+ switch (k64Cnt & 3)
+ {
+ case 1:
+ gSBox[i*2] = gMDS0[(P[P_01,b0] & 0xff) ^ M_b0(k0)];
+ gSBox[i*2+1] = gMDS1[(P[P_11,b1] & 0xff) ^ M_b1(k0)];
+ gSBox[i*2+0x200] = gMDS2[(P[P_21,b2] & 0xff) ^ M_b2(k0)];
+ gSBox[i*2+0x201] = gMDS3[(P[P_31,b3] & 0xff) ^ M_b3(k0)];
+ break;
+ case 0: // 256 bits of key
+ b0 = (P[P_04,b0] & 0xff) ^ M_b0(k3);
+ b1 = (P[P_14,b1] & 0xff) ^ M_b1(k3);
+ b2 = (P[P_24,b2] & 0xff) ^ M_b2(k3);
+ b3 = (P[P_34,b3] & 0xff) ^ M_b3(k3);
+ // fall through, having pre-processed b[0]..b[3] with k32[3]
+ goto case 3;
+ case 3: // 192 bits of key
+ b0 = (P[P_03,b0] & 0xff) ^ M_b0(k2);
+ b1 = (P[P_13,b1] & 0xff) ^ M_b1(k2);
+ b2 = (P[P_23,b2] & 0xff) ^ M_b2(k2);
+ b3 = (P[P_33,b3] & 0xff) ^ M_b3(k2);
+ // fall through, having pre-processed b[0]..b[3] with k32[2]
+ goto case 2;
+ case 2: // 128 bits of key
+ gSBox[i * 2] = gMDS0[(P[P_01, (P[P_02, b0] & 0xff) ^ M_b0(k1)] & 0xff) ^ M_b0(k0)];
+ gSBox[i*2+1] = gMDS1[(P[P_11,(P[P_12,b1] & 0xff) ^ M_b1(k1)] & 0xff) ^ M_b1(k0)];
+ gSBox[i*2+0x200] = gMDS2[(P[P_21,(P[P_22,b2] & 0xff) ^ M_b2(k1)] & 0xff) ^ M_b2(k0)];
+ gSBox[i * 2 + 0x201] = gMDS3[(P[P_31, (P[P_32, b3] & 0xff) ^ M_b3(k1)] & 0xff) ^ M_b3(k0)];
+ break;
+ }
+ }
+
+ /*
+ * the function exits having setup the gSBox with the
+ * input key material.
+ */
+ }
+
+ /**
+ * Encrypt the given input starting at the given offset and place
+ * the result in the provided buffer starting at the given offset.
+ * The input will be an exact multiple of our blocksize.
+ *
+ * encryptBlock uses the pre-calculated gSBox[] and subKey[]
+ * arrays.
+ */
+ private void EncryptBlock(
+ byte[] src,
+ int srcIndex,
+ byte[] dst,
+ int dstIndex)
+ {
+ int x0 = BytesTo32Bits(src, srcIndex) ^ gSubKeys[INPUT_WHITEN];
+ int x1 = BytesTo32Bits(src, srcIndex + 4) ^ gSubKeys[INPUT_WHITEN + 1];
+ int x2 = BytesTo32Bits(src, srcIndex + 8) ^ gSubKeys[INPUT_WHITEN + 2];
+ int x3 = BytesTo32Bits(src, srcIndex + 12) ^ gSubKeys[INPUT_WHITEN + 3];
+
+ int k = ROUND_SUBKEYS;
+ int t0, t1;
+ for (int r = 0; r < ROUNDS; r +=2)
+ {
+ t0 = Fe32_0(x0);
+ t1 = Fe32_3(x1);
+ x2 ^= t0 + t1 + gSubKeys[k++];
+ x2 = (int)((uint)x2 >>1) | x2 << 31;
+ x3 = (x3 << 1 | (int) ((uint)x3 >> 31)) ^ (t0 + 2*t1 + gSubKeys[k++]);
+
+ t0 = Fe32_0(x2);
+ t1 = Fe32_3(x3);
+ x0 ^= t0 + t1 + gSubKeys[k++];
+ x0 = (int) ((uint)x0 >>1) | x0 << 31;
+ x1 = (x1 << 1 | (int)((uint)x1 >> 31)) ^ (t0 + 2*t1 + gSubKeys[k++]);
+ }
+
+ Bits32ToBytes(x2 ^ gSubKeys[OUTPUT_WHITEN], dst, dstIndex);
+ Bits32ToBytes(x3 ^ gSubKeys[OUTPUT_WHITEN + 1], dst, dstIndex + 4);
+ Bits32ToBytes(x0 ^ gSubKeys[OUTPUT_WHITEN + 2], dst, dstIndex + 8);
+ Bits32ToBytes(x1 ^ gSubKeys[OUTPUT_WHITEN + 3], dst, dstIndex + 12);
+ }
+
+ /**
+ * Decrypt the given input starting at the given offset and place
+ * the result in the provided buffer starting at the given offset.
+ * The input will be an exact multiple of our blocksize.
+ */
+ private void DecryptBlock(
+ byte[] src,
+ int srcIndex,
+ byte[] dst,
+ int dstIndex)
+ {
+ int x2 = BytesTo32Bits(src, srcIndex) ^ gSubKeys[OUTPUT_WHITEN];
+ int x3 = BytesTo32Bits(src, srcIndex+4) ^ gSubKeys[OUTPUT_WHITEN + 1];
+ int x0 = BytesTo32Bits(src, srcIndex+8) ^ gSubKeys[OUTPUT_WHITEN + 2];
+ int x1 = BytesTo32Bits(src, srcIndex+12) ^ gSubKeys[OUTPUT_WHITEN + 3];
+
+ int k = ROUND_SUBKEYS + 2 * ROUNDS -1 ;
+ int t0, t1;
+ for (int r = 0; r< ROUNDS ; r +=2)
+ {
+ t0 = Fe32_0(x2);
+ t1 = Fe32_3(x3);
+ x1 ^= t0 + 2*t1 + gSubKeys[k--];
+ x0 = (x0 << 1 | (int)((uint) x0 >> 31)) ^ (t0 + t1 + gSubKeys[k--]);
+ x1 = (int) ((uint)x1 >>1) | x1 << 31;
+
+ t0 = Fe32_0(x0);
+ t1 = Fe32_3(x1);
+ x3 ^= t0 + 2*t1 + gSubKeys[k--];
+ x2 = (x2 << 1 | (int)((uint)x2 >> 31)) ^ (t0 + t1 + gSubKeys[k--]);
+ x3 = (int)((uint)x3 >>1) | x3 << 31;
+ }
+
+ Bits32ToBytes(x0 ^ gSubKeys[INPUT_WHITEN], dst, dstIndex);
+ Bits32ToBytes(x1 ^ gSubKeys[INPUT_WHITEN + 1], dst, dstIndex + 4);
+ Bits32ToBytes(x2 ^ gSubKeys[INPUT_WHITEN + 2], dst, dstIndex + 8);
+ Bits32ToBytes(x3 ^ gSubKeys[INPUT_WHITEN + 3], dst, dstIndex + 12);
+ }
+
+ /*
+ * TODO: This can be optimised and made cleaner by combining
+ * the functionality in this function and applying it appropriately
+ * to the creation of the subkeys during key setup.
+ */
+ private int F32(int x, int[] k32)
+ {
+ int b0 = M_b0(x);
+ int b1 = M_b1(x);
+ int b2 = M_b2(x);
+ int b3 = M_b3(x);
+ int k0 = k32[0];
+ int k1 = k32[1];
+ int k2 = k32[2];
+ int k3 = k32[3];
+
+ int result = 0;
+ switch (k64Cnt & 3)
+ {
+ case 1:
+ result = gMDS0[(P[P_01,b0] & 0xff) ^ M_b0(k0)] ^
+ gMDS1[(P[P_11,b1] & 0xff) ^ M_b1(k0)] ^
+ gMDS2[(P[P_21,b2] & 0xff) ^ M_b2(k0)] ^
+ gMDS3[(P[P_31,b3] & 0xff) ^ M_b3(k0)];
+ break;
+ case 0: /* 256 bits of key */
+ b0 = (P[P_04,b0] & 0xff) ^ M_b0(k3);
+ b1 = (P[P_14,b1] & 0xff) ^ M_b1(k3);
+ b2 = (P[P_24,b2] & 0xff) ^ M_b2(k3);
+ b3 = (P[P_34,b3] & 0xff) ^ M_b3(k3);
+ goto case 3;
+ case 3:
+ b0 = (P[P_03,b0] & 0xff) ^ M_b0(k2);
+ b1 = (P[P_13,b1] & 0xff) ^ M_b1(k2);
+ b2 = (P[P_23,b2] & 0xff) ^ M_b2(k2);
+ b3 = (P[P_33,b3] & 0xff) ^ M_b3(k2);
+ goto case 2;
+ case 2:
+ result =
+ gMDS0[(P[P_01,(P[P_02,b0]&0xff)^M_b0(k1)]&0xff)^M_b0(k0)] ^
+ gMDS1[(P[P_11,(P[P_12,b1]&0xff)^M_b1(k1)]&0xff)^M_b1(k0)] ^
+ gMDS2[(P[P_21,(P[P_22,b2]&0xff)^M_b2(k1)]&0xff)^M_b2(k0)] ^
+ gMDS3[(P[P_31,(P[P_32,b3]&0xff)^M_b3(k1)]&0xff)^M_b3(k0)];
+ break;
+ }
+ return result;
+ }
+
+ /**
+ * Use (12, 8) Reed-Solomon code over GF(256) to produce
+ * a key S-box 32-bit entity from 2 key material 32-bit
+ * entities.
+ *
+ * @param k0 first 32-bit entity
+ * @param k1 second 32-bit entity
+ * @return Remainder polynomial Generated using RS code
+ */
+ private int RS_MDS_Encode(int k0, int k1)
+ {
+ int r = k1;
+ for (int i = 0 ; i < 4 ; i++) // shift 1 byte at a time
+ {
+ r = RS_rem(r);
+ }
+ r ^= k0;
+ for (int i=0 ; i < 4 ; i++)
+ {
+ r = RS_rem(r);
+ }
+
+ return r;
+ }
+
+ /**
+ * Reed-Solomon code parameters: (12,8) reversible code:
+ * <p>
+ * <pre>
+ * G(x) = x^4 + (a+1/a)x^3 + ax^2 + (a+1/a)x + 1
+ * </pre>
+ * where a = primitive root of field generator 0x14D
+ * </p>
+ */
+ private int RS_rem(int x)
+ {
+ int b = (int) (((uint)x >> 24) & 0xff);
+ int g2 = ((b << 1) ^
+ ((b & 0x80) != 0 ? RS_GF_FDBK : 0)) & 0xff;
+ int g3 = ( (int)((uint)b >> 1) ^
+ ((b & 0x01) != 0 ? (int)((uint)RS_GF_FDBK >> 1) : 0)) ^ g2 ;
+ return ((x << 8) ^ (g3 << 24) ^ (g2 << 16) ^ (g3 << 8) ^ b);
+ }
+
+ private int LFSR1(int x)
+ {
+ return (x >> 1) ^
+ (((x & 0x01) != 0) ? GF256_FDBK_2 : 0);
+ }
+
+ private int LFSR2(int x)
+ {
+ return (x >> 2) ^
+ (((x & 0x02) != 0) ? GF256_FDBK_2 : 0) ^
+ (((x & 0x01) != 0) ? GF256_FDBK_4 : 0);
+ }
+
+ private int Mx_X(int x)
+ {
+ return x ^ LFSR2(x);
+ } // 5B
+
+ private int Mx_Y(int x)
+ {
+ return x ^ LFSR1(x) ^ LFSR2(x);
+ } // EF
+
+ private int M_b0(int x)
+ {
+ return x & 0xff;
+ }
+
+ private int M_b1(int x)
+ {
+ return (int)((uint)x >> 8) & 0xff;
+ }
+
+ private int M_b2(int x)
+ {
+ return (int)((uint)x >> 16) & 0xff;
+ }
+
+ private int M_b3(int x)
+ {
+ return (int)((uint)x >> 24) & 0xff;
+ }
+
+ private int Fe32_0(int x)
+ {
+ return gSBox[ 0x000 + 2*(x & 0xff) ] ^
+ gSBox[ 0x001 + 2*((int)((uint)x >> 8) & 0xff) ] ^
+ gSBox[ 0x200 + 2*((int)((uint)x >> 16) & 0xff) ] ^
+ gSBox[ 0x201 + 2*((int)((uint)x >> 24) & 0xff) ];
+ }
+
+ private int Fe32_3(int x)
+ {
+ return gSBox[ 0x000 + 2*((int)((uint)x >> 24) & 0xff) ] ^
+ gSBox[ 0x001 + 2*(x & 0xff) ] ^
+ gSBox[ 0x200 + 2*((int)((uint)x >> 8) & 0xff) ] ^
+ gSBox[ 0x201 + 2*((int)((uint)x >> 16) & 0xff) ];
+ }
+
+ private int BytesTo32Bits(byte[] b, int p)
+ {
+ return ((b[p] & 0xff) ) |
+ ((b[p+1] & 0xff) << 8) |
+ ((b[p+2] & 0xff) << 16) |
+ ((b[p+3] & 0xff) << 24);
+ }
+
+ private void Bits32ToBytes(int inData, byte[] b, int offset)
+ {
+ b[offset] = (byte)inData;
+ b[offset + 1] = (byte)(inData >> 8);
+ b[offset + 2] = (byte)(inData >> 16);
+ b[offset + 3] = (byte)(inData >> 24);
+ }
+ }
+
+}
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