/*
A C# implementation of the Twofish cipher
By Shaun Wilde
An article on integrating a C# implementation of the Twofish cipher into the
.NET framework.
http://www.codeproject.com/KB/recipes/twofish_csharp.aspx
The Code Project Open License (CPOL) 1.02
http://www.codeproject.com/info/cpol10.aspx
Download a copy of the CPOL.
http://www.codeproject.com/info/CPOL.zip
*/
//#define FEISTEL
using System;
using System.Diagnostics;
using System.Security.Cryptography;
namespace TwofishCipher.Crypto
{
///
/// Summary description for TwofishBase.
///
internal class TwofishBase
{
public enum EncryptionDirection
{
Encrypting,
Decrypting
}
public TwofishBase()
{
}
protected int inputBlockSize = BLOCK_SIZE/8;
protected int outputBlockSize = BLOCK_SIZE/8;
/*
+*****************************************************************************
*
* Function Name: f32
*
* Function: Run four bytes through keyed S-boxes and apply MDS matrix
*
* Arguments: x = input to f function
* k32 = pointer to key dwords
* keyLen = total key length (k32 --> keyLey/2 bits)
*
* Return: The output of the keyed permutation applied to x.
*
* Notes:
* This function is a keyed 32-bit permutation. It is the major building
* block for the Twofish round function, including the four keyed 8x8
* permutations and the 4x4 MDS matrix multiply. This function is used
* both for generating round subkeys and within the round function on the
* block being encrypted.
*
* This version is fairly slow and pedagogical, although a smartcard would
* probably perform the operation exactly this way in firmware. For
* ultimate performance, the entire operation can be completed with four
* lookups into four 256x32-bit tables, with three dword xors.
*
* The MDS matrix is defined in TABLE.H. To multiply by Mij, just use the
* macro Mij(x).
*
-****************************************************************************/
private static uint f32(uint x,ref uint[] k32,int keyLen)
{
byte[] b = {b0(x),b1(x),b2(x),b3(x)};
/* Run each byte thru 8x8 S-boxes, xoring with key byte at each stage. */
/* Note that each byte goes through a different combination of S-boxes.*/
//*((DWORD *)b) = Bswap(x); /* make b[0] = LSB, b[3] = MSB */
switch (((keyLen + 63)/64) & 3)
{
case 0: /* 256 bits of key */
b[0] = (byte)(P8x8[P_04,b[0]] ^ b0(k32[3]));
b[1] = (byte)(P8x8[P_14,b[1]] ^ b1(k32[3]));
b[2] = (byte)(P8x8[P_24,b[2]] ^ b2(k32[3]));
b[3] = (byte)(P8x8[P_34,b[3]] ^ b3(k32[3]));
/* fall thru, having pre-processed b[0]..b[3] with k32[3] */
goto case 3;
case 3: /* 192 bits of key */
b[0] = (byte)(P8x8[P_03,b[0]] ^ b0(k32[2]));
b[1] = (byte)(P8x8[P_13,b[1]] ^ b1(k32[2]));
b[2] = (byte)(P8x8[P_23,b[2]] ^ b2(k32[2]));
b[3] = (byte)(P8x8[P_33,b[3]] ^ b3(k32[2]));
/* fall thru, having pre-processed b[0]..b[3] with k32[2] */
goto case 2;
case 2: /* 128 bits of key */
b[0] = P8x8[P_00, P8x8[P_01, P8x8[P_02, b[0]] ^ b0(k32[1])] ^ b0(k32[0])];
b[1] = P8x8[P_10, P8x8[P_11, P8x8[P_12, b[1]] ^ b1(k32[1])] ^ b1(k32[0])];
b[2] = P8x8[P_20, P8x8[P_21, P8x8[P_22, b[2]] ^ b2(k32[1])] ^ b2(k32[0])];
b[3] = P8x8[P_30, P8x8[P_31, P8x8[P_32, b[3]] ^ b3(k32[1])] ^ b3(k32[0])];
break;
}
/* Now perform the MDS matrix multiply inline. */
return (uint)((M00(b[0]) ^ M01(b[1]) ^ M02(b[2]) ^ M03(b[3]))) ^
(uint)((M10(b[0]) ^ M11(b[1]) ^ M12(b[2]) ^ M13(b[3])) << 8) ^
(uint)((M20(b[0]) ^ M21(b[1]) ^ M22(b[2]) ^ M23(b[3])) << 16) ^
(uint)((M30(b[0]) ^ M31(b[1]) ^ M32(b[2]) ^ M33(b[3])) << 24) ;
}
/*
+*****************************************************************************
*
* Function Name: reKey
*
* Function: Initialize the Twofish key schedule from key32
*
* Arguments: key = ptr to keyInstance to be initialized
*
* Return: TRUE on success
*
* Notes:
* Here we precompute all the round subkeys, although that is not actually
* required. For example, on a smartcard, the round subkeys can
* be generated on-the-fly using f32()
*
-****************************************************************************/
protected bool reKey(int keyLen, ref uint[] key32)
{
int i,k64Cnt;
keyLength = keyLen;
rounds = numRounds[(keyLen-1)/64];
int subkeyCnt = ROUND_SUBKEYS + 2*rounds;
uint A,B;
uint[] k32e = new uint[MAX_KEY_BITS/64];
uint[] k32o = new uint[MAX_KEY_BITS/64]; /* even/odd key dwords */
k64Cnt=(keyLen+63)/64; /* round up to next multiple of 64 bits */
for (i=0;i=0;r--) /* main Twofish decryption loop */
{
t0 = f32( x[0] ,ref sboxKeys,keyLength);
t1 = f32(ROL(x[1],8),ref sboxKeys,keyLength);
x[2] = ROL(x[2],1);
x[2]^= t0 + t1 + subKeys[ROUND_SUBKEYS+2*r ]; /* PHT, round keys */
x[3]^= t0 + 2*t1 + subKeys[ROUND_SUBKEYS+2*r+1];
x[3] = ROR(x[3],1);
if (r>0) /* unswap, except for last round */
{
t0 = x[0]; x[0]= x[2]; x[2] = t0;
t1 = x[1]; x[1]= x[3]; x[3] = t1;
}
}
for (int i=0;i0) ? k0 : k1; /* merge in 32 more key bits */
for (j=0;j<4;j++) /* shift one byte at a time */
RS_rem(ref r);
}
return r;
}
protected uint[] sboxKeys = new uint[MAX_KEY_BITS/64]; /* key bits used for S-boxes */
protected uint[] subKeys = new uint[TOTAL_SUBKEYS]; /* round subkeys, input/output whitening bits */
protected uint[] Key = {0,0,0,0,0,0,0,0}; //new int[MAX_KEY_BITS/32];
protected uint[] IV = {0,0,0,0}; // this should be one block size
private int keyLength;
private int rounds;
protected CipherMode cipherMode = CipherMode.ECB;
#region These are all the definitions that were found in AES.H
static private readonly int BLOCK_SIZE = 128; /* number of bits per block */
static private readonly int MAX_ROUNDS = 16; /* max # rounds (for allocating subkey array) */
static private readonly int ROUNDS_128 = 16; /* default number of rounds for 128-bit keys*/
static private readonly int ROUNDS_192 = 16; /* default number of rounds for 192-bit keys*/
static private readonly int ROUNDS_256 = 16; /* default number of rounds for 256-bit keys*/
static private readonly int MAX_KEY_BITS = 256; /* max number of bits of key */
// static private readonly int MIN_KEY_BITS = 128; /* min number of bits of key (zero pad) */
//#define VALID_SIG 0x48534946 /* initialization signature ('FISH') */
//#define MCT_OUTER 400 /* MCT outer loop */
//#define MCT_INNER 10000 /* MCT inner loop */
//#define REENTRANT 1 /* nonzero forces reentrant code (slightly slower) */
static private readonly int INPUT_WHITEN = 0; /* subkey array indices */
static private readonly int OUTPUT_WHITEN = (INPUT_WHITEN + BLOCK_SIZE/32);
static private readonly int ROUND_SUBKEYS = (OUTPUT_WHITEN + BLOCK_SIZE/32); /* use 2 * (# rounds) */
static private readonly int TOTAL_SUBKEYS = (ROUND_SUBKEYS + 2*MAX_ROUNDS);
#endregion
#region These are all the definitions that were found in TABLE.H that we need
/* for computing subkeys */
static private readonly uint SK_STEP = 0x02020202u;
static private readonly uint SK_BUMP = 0x01010101u;
static private readonly int SK_ROTL = 9;
/* Reed-Solomon code parameters: (12,8) reversible code
g(x) = x**4 + (a + 1/a) x**3 + a x**2 + (a + 1/a) x + 1
where a = primitive root of field generator 0x14D */
static private readonly uint RS_GF_FDBK = 0x14D; /* field generator */
static private void RS_rem(ref uint x)
{
byte b = (byte) (x >> 24);
// TODO: maybe change g2 and g3 to bytes
uint g2 = (uint)(((b << 1) ^ (((b & 0x80)==0x80) ? RS_GF_FDBK : 0 )) & 0xFF);
uint g3 = (uint)(((b >> 1) & 0x7F) ^ (((b & 1)==1) ? RS_GF_FDBK >> 1 : 0 ) ^ g2) ;
x = (x << 8) ^ (g3 << 24) ^ (g2 << 16) ^ (g3 << 8) ^ b;
}
/* Macros for the MDS matrix
* The MDS matrix is (using primitive polynomial 169):
* 01 EF 5B 5B
* 5B EF EF 01
* EF 5B 01 EF
* EF 01 EF 5B
*----------------------------------------------------------------
* More statistical properties of this matrix (from MDS.EXE output):
*
* Min Hamming weight (one byte difference) = 8. Max=26. Total = 1020.
* Prob[8]: 7 23 42 20 52 95 88 94 121 128 91
* 102 76 41 24 8 4 1 3 0 0 0
* Runs[8]: 2 4 5 6 7 8 9 11
* MSBs[8]: 1 4 15 8 18 38 40 43
* HW= 8: 05040705 0A080E0A 14101C14 28203828 50407050 01499101 A080E0A0
* HW= 9: 04050707 080A0E0E 10141C1C 20283838 40507070 80A0E0E0 C6432020 07070504
* 0E0E0A08 1C1C1410 38382820 70705040 E0E0A080 202043C6 05070407 0A0E080E
* 141C101C 28382038 50704070 A0E080E0 4320C620 02924B02 089A4508
* Min Hamming weight (two byte difference) = 3. Max=28. Total = 390150.
* Prob[3]: 7 18 55 149 270 914 2185 5761 11363 20719 32079
* 43492 51612 53851 52098 42015 31117 20854 11538 6223 2492 1033
* MDS OK, ROR: 6+ 7+ 8+ 9+ 10+ 11+ 12+ 13+ 14+ 15+ 16+
* 17+ 18+ 19+ 20+ 21+ 22+ 23+ 24+ 25+ 26+
*/
static private readonly int MDS_GF_FDBK = 0x169; /* primitive polynomial for GF(256)*/
static private int LFSR1(int x)
{
return ( ((x) >> 1) ^ ((((x) & 0x01)==0x01) ? MDS_GF_FDBK/2 : 0));
}
static private int LFSR2(int x)
{
return ( ((x) >> 2) ^ ((((x) & 0x02)==0x02) ? MDS_GF_FDBK/2 : 0) ^
((((x) & 0x01)==0x01) ? MDS_GF_FDBK/4 : 0));
}
// TODO: not the most efficient use of code but it allows us to update the code a lot quicker we can possibly optimize this code once we have got it all working
static private int Mx_1(int x)
{
return x; /* force result to int so << will work */
}
static private int Mx_X(int x)
{
return x ^ LFSR2(x); /* 5B */
}
static private int Mx_Y(int x)
{
return x ^ LFSR1(x) ^ LFSR2(x); /* EF */
}
static private int M00(int x)
{
return Mul_1(x);
}
static private int M01(int x)
{
return Mul_Y(x);
}
static private int M02(int x)
{
return Mul_X(x);
}
static private int M03(int x)
{
return Mul_X(x);
}
static private int M10(int x)
{
return Mul_X(x);
}
static private int M11(int x)
{
return Mul_Y(x);
}
static private int M12(int x)
{
return Mul_Y(x);
}
static private int M13(int x)
{
return Mul_1(x);
}
static private int M20(int x)
{
return Mul_Y(x);
}
static private int M21(int x)
{
return Mul_X(x);
}
static private int M22(int x)
{
return Mul_1(x);
}
static private int M23(int x)
{
return Mul_Y(x);
}
static private int M30(int x)
{
return Mul_Y(x);
}
static private int M31(int x)
{
return Mul_1(x);
}
static private int M32(int x)
{
return Mul_Y(x);
}
static private int M33(int x)
{
return Mul_X(x);
}
static private int Mul_1(int x)
{
return Mx_1(x);
}
static private int Mul_X(int x)
{
return Mx_X(x);
}
static private int Mul_Y(int x)
{
return Mx_Y(x);
}
/* Define the fixed p0/p1 permutations used in keyed S-box lookup.
By changing the following constant definitions for P_ij, the S-boxes will
automatically get changed in all the Twofish source code. Note that P_i0 is
the "outermost" 8x8 permutation applied. See the f32() function to see
how these constants are to be used.
*/
static private readonly int P_00 = 1; /* "outermost" permutation */
static private readonly int P_01 = 0;
static private readonly int P_02 = 0;
static private readonly int P_03 = (P_01^1); /* "extend" to larger key sizes */
static private readonly int P_04 = 1;
static private readonly int P_10 = 0;
static private readonly int P_11 = 0;
static private readonly int P_12 = 1;
static private readonly int P_13 = (P_11^1);
static private readonly int P_14 = 0;
static private readonly int P_20 = 1;
static private readonly int P_21 = 1;
static private readonly int P_22 = 0;
static private readonly int P_23 = (P_21^1);
static private readonly int P_24 = 0;
static private readonly int P_30 = 0;
static private readonly int P_31 = 1;
static private readonly int P_32 = 1;
static private readonly int P_33 = (P_31^1);
static private readonly int P_34 = 1;
/* fixed 8x8 permutation S-boxes */
/***********************************************************************
* 07:07:14 05/30/98 [4x4] TestCnt=256. keySize=128. CRC=4BD14D9E.
* maxKeyed: dpMax = 18. lpMax =100. fixPt = 8. skXor = 0. skDup = 6.
* log2(dpMax[ 6..18])= --- 15.42 1.33 0.89 4.05 7.98 12.05
* log2(lpMax[ 7..12])= 9.32 1.01 1.16 4.23 8.02 12.45
* log2(fixPt[ 0.. 8])= 1.44 1.44 2.44 4.06 6.01 8.21 11.07 14.09 17.00
* log2(skXor[ 0.. 0])
* log2(skDup[ 0.. 6])= --- 2.37 0.44 3.94 8.36 13.04 17.99
***********************************************************************/
static private byte[,] P8x8 =
{
/* p0: */
/* dpMax = 10. lpMax = 64. cycleCnt= 1 1 1 0. */
/* 817D6F320B59ECA4.ECB81235F4A6709D.BA5E6D90C8F32471.D7F4126E9B3085CA. */
/* Karnaugh maps:
* 0111 0001 0011 1010. 0001 1001 1100 1111. 1001 1110 0011 1110. 1101 0101 1111 1001.
* 0101 1111 1100 0100. 1011 0101 0010 0000. 0101 1000 1100 0101. 1000 0111 0011 0010.
* 0000 1001 1110 1101. 1011 1000 1010 0011. 0011 1001 0101 0000. 0100 0010 0101 1011.
* 0111 0100 0001 0110. 1000 1011 1110 1001. 0011 0011 1001 1101. 1101 0101 0000 1100.
*/
{
0xA9, 0x67, 0xB3, 0xE8, 0x04, 0xFD, 0xA3, 0x76,
0x9A, 0x92, 0x80, 0x78, 0xE4, 0xDD, 0xD1, 0x38,
0x0D, 0xC6, 0x35, 0x98, 0x18, 0xF7, 0xEC, 0x6C,
0x43, 0x75, 0x37, 0x26, 0xFA, 0x13, 0x94, 0x48,
0xF2, 0xD0, 0x8B, 0x30, 0x84, 0x54, 0xDF, 0x23,
0x19, 0x5B, 0x3D, 0x59, 0xF3, 0xAE, 0xA2, 0x82,
0x63, 0x01, 0x83, 0x2E, 0xD9, 0x51, 0x9B, 0x7C,
0xA6, 0xEB, 0xA5, 0xBE, 0x16, 0x0C, 0xE3, 0x61,
0xC0, 0x8C, 0x3A, 0xF5, 0x73, 0x2C, 0x25, 0x0B,
0xBB, 0x4E, 0x89, 0x6B, 0x53, 0x6A, 0xB4, 0xF1,
0xE1, 0xE6, 0xBD, 0x45, 0xE2, 0xF4, 0xB6, 0x66,
0xCC, 0x95, 0x03, 0x56, 0xD4, 0x1C, 0x1E, 0xD7,
0xFB, 0xC3, 0x8E, 0xB5, 0xE9, 0xCF, 0xBF, 0xBA,
0xEA, 0x77, 0x39, 0xAF, 0x33, 0xC9, 0x62, 0x71,
0x81, 0x79, 0x09, 0xAD, 0x24, 0xCD, 0xF9, 0xD8,
0xE5, 0xC5, 0xB9, 0x4D, 0x44, 0x08, 0x86, 0xE7,
0xA1, 0x1D, 0xAA, 0xED, 0x06, 0x70, 0xB2, 0xD2,
0x41, 0x7B, 0xA0, 0x11, 0x31, 0xC2, 0x27, 0x90,
0x20, 0xF6, 0x60, 0xFF, 0x96, 0x5C, 0xB1, 0xAB,
0x9E, 0x9C, 0x52, 0x1B, 0x5F, 0x93, 0x0A, 0xEF,
0x91, 0x85, 0x49, 0xEE, 0x2D, 0x4F, 0x8F, 0x3B,
0x47, 0x87, 0x6D, 0x46, 0xD6, 0x3E, 0x69, 0x64,
0x2A, 0xCE, 0xCB, 0x2F, 0xFC, 0x97, 0x05, 0x7A,
0xAC, 0x7F, 0xD5, 0x1A, 0x4B, 0x0E, 0xA7, 0x5A,
0x28, 0x14, 0x3F, 0x29, 0x88, 0x3C, 0x4C, 0x02,
0xB8, 0xDA, 0xB0, 0x17, 0x55, 0x1F, 0x8A, 0x7D,
0x57, 0xC7, 0x8D, 0x74, 0xB7, 0xC4, 0x9F, 0x72,
0x7E, 0x15, 0x22, 0x12, 0x58, 0x07, 0x99, 0x34,
0x6E, 0x50, 0xDE, 0x68, 0x65, 0xBC, 0xDB, 0xF8,
0xC8, 0xA8, 0x2B, 0x40, 0xDC, 0xFE, 0x32, 0xA4,
0xCA, 0x10, 0x21, 0xF0, 0xD3, 0x5D, 0x0F, 0x00,
0x6F, 0x9D, 0x36, 0x42, 0x4A, 0x5E, 0xC1, 0xE0
},
/* p1: */
/* dpMax = 10. lpMax = 64. cycleCnt= 2 0 0 1. */
/* 28BDF76E31940AC5.1E2B4C376DA5F908.4C75169A0ED82B3F.B951C3DE647F208A. */
/* Karnaugh maps:
* 0011 1001 0010 0111. 1010 0111 0100 0110. 0011 0001 1111 0100. 1111 1000 0001 1100.
* 1100 1111 1111 1010. 0011 0011 1110 0100. 1001 0110 0100 0011. 0101 0110 1011 1011.
* 0010 0100 0011 0101. 1100 1000 1000 1110. 0111 1111 0010 0110. 0000 1010 0000 0011.
* 1101 1000 0010 0001. 0110 1001 1110 0101. 0001 0100 0101 0111. 0011 1011 1111 0010.
*/
{
0x75, 0xF3, 0xC6, 0xF4, 0xDB, 0x7B, 0xFB, 0xC8,
0x4A, 0xD3, 0xE6, 0x6B, 0x45, 0x7D, 0xE8, 0x4B,
0xD6, 0x32, 0xD8, 0xFD, 0x37, 0x71, 0xF1, 0xE1,
0x30, 0x0F, 0xF8, 0x1B, 0x87, 0xFA, 0x06, 0x3F,
0x5E, 0xBA, 0xAE, 0x5B, 0x8A, 0x00, 0xBC, 0x9D,
0x6D, 0xC1, 0xB1, 0x0E, 0x80, 0x5D, 0xD2, 0xD5,
0xA0, 0x84, 0x07, 0x14, 0xB5, 0x90, 0x2C, 0xA3,
0xB2, 0x73, 0x4C, 0x54, 0x92, 0x74, 0x36, 0x51,
0x38, 0xB0, 0xBD, 0x5A, 0xFC, 0x60, 0x62, 0x96,
0x6C, 0x42, 0xF7, 0x10, 0x7C, 0x28, 0x27, 0x8C,
0x13, 0x95, 0x9C, 0xC7, 0x24, 0x46, 0x3B, 0x70,
0xCA, 0xE3, 0x85, 0xCB, 0x11, 0xD0, 0x93, 0xB8,
0xA6, 0x83, 0x20, 0xFF, 0x9F, 0x77, 0xC3, 0xCC,
0x03, 0x6F, 0x08, 0xBF, 0x40, 0xE7, 0x2B, 0xE2,
0x79, 0x0C, 0xAA, 0x82, 0x41, 0x3A, 0xEA, 0xB9,
0xE4, 0x9A, 0xA4, 0x97, 0x7E, 0xDA, 0x7A, 0x17,
0x66, 0x94, 0xA1, 0x1D, 0x3D, 0xF0, 0xDE, 0xB3,
0x0B, 0x72, 0xA7, 0x1C, 0xEF, 0xD1, 0x53, 0x3E,
0x8F, 0x33, 0x26, 0x5F, 0xEC, 0x76, 0x2A, 0x49,
0x81, 0x88, 0xEE, 0x21, 0xC4, 0x1A, 0xEB, 0xD9,
0xC5, 0x39, 0x99, 0xCD, 0xAD, 0x31, 0x8B, 0x01,
0x18, 0x23, 0xDD, 0x1F, 0x4E, 0x2D, 0xF9, 0x48,
0x4F, 0xF2, 0x65, 0x8E, 0x78, 0x5C, 0x58, 0x19,
0x8D, 0xE5, 0x98, 0x57, 0x67, 0x7F, 0x05, 0x64,
0xAF, 0x63, 0xB6, 0xFE, 0xF5, 0xB7, 0x3C, 0xA5,
0xCE, 0xE9, 0x68, 0x44, 0xE0, 0x4D, 0x43, 0x69,
0x29, 0x2E, 0xAC, 0x15, 0x59, 0xA8, 0x0A, 0x9E,
0x6E, 0x47, 0xDF, 0x34, 0x35, 0x6A, 0xCF, 0xDC,
0x22, 0xC9, 0xC0, 0x9B, 0x89, 0xD4, 0xED, 0xAB,
0x12, 0xA2, 0x0D, 0x52, 0xBB, 0x02, 0x2F, 0xA9,
0xD7, 0x61, 0x1E, 0xB4, 0x50, 0x04, 0xF6, 0xC2,
0x16, 0x25, 0x86, 0x56, 0x55, 0x09, 0xBE, 0x91
}
};
#endregion
#region These are all the definitions that were found in PLATFORM.H that we need
// left rotation
private static uint ROL(uint x, int n)
{
return ( ((x) << ((n) & 0x1F)) | (x) >> (32-((n) & 0x1F)) );
}
// right rotation
private static uint ROR(uint x,int n)
{
return (((x) >> ((n) & 0x1F)) | ((x) << (32-((n) & 0x1F))));
}
// first byte
protected static byte b0(uint x)
{
return (byte)(x );//& 0xFF);
}
// second byte
protected static byte b1(uint x)
{
return (byte)((x >> 8));// & (0xFF));
}
// third byte
protected static byte b2(uint x)
{
return (byte)((x >> 16));// & (0xFF));
}
// fourth byte
protected static byte b3(uint x)
{
return (byte)((x >> 24));// & (0xFF));
}
#endregion
}
}