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AESLightEngine
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S: byte[]
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Si: byte[]
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rcon: int[]
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shift(int, int): int
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m1: int
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m2: int
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m3: int
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m4: int
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m5: int
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FFmulX(int): int
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FFmulX2(int): int
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mcol(int): int
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inv_mcol(int): int
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subWord(int): int
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generateWorkingKey(byte[], boolean): int[][]
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ROUNDS: int
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WorkingKey: int[][]
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C0: int
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C1: int
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C2: int
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C3: int
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forEncryption: boolean
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BLOCK_SIZE: int
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AESLightEngine(): void
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init(boolean, CipherParameters): void
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getAlgorithmName(): String
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getBlockSize(): int
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processBlock(byte[], int, byte[], int): int
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reset(): void
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unpackBlock(byte[], int): void
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packBlock(byte[], int): void
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encryptBlock(int[][]): void
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decryptBlock(int[][]): void
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package org.bouncycastle.crypto.engines;
import org.bouncycastle.crypto.BlockCipher;
import org.bouncycastle.crypto.CipherParameters;
import org.bouncycastle.crypto.DataLengthException;
import org.bouncycastle.crypto.OutputLengthException;
import org.bouncycastle.crypto.params.KeyParameter;
import org.bouncycastle.util.Pack;
an implementation of the AES (Rijndael), from FIPS-197.
For further details see: http://csrc.nist.gov/encryption/aes/.
This implementation is based on optimizations from Dr. Brian Gladman's paper and C code at
http://fp.gladman.plus.com/cryptography_technology/rijndael/
There are three levels of tradeoff of speed vs memory
Because java has no preprocessor, they are written as three separate classes from which to choose
The fastest uses 8Kbytes of static tables to precompute round calculations, 4 256 word tables for encryption
and 4 for decryption.
The middle performance version uses only one 256 word table for each, for a total of 2Kbytes,
adding 12 rotate operations per round to compute the values contained in the other tables from
the contents of the first
The slowest version uses no static tables at all and computes the values
in each round.
This file contains the slowest performance version with no static tables
for round precomputation, but it has the smallest foot print.
/**
* an implementation of the AES (Rijndael), from FIPS-197.
* <p>
* For further details see: <a href="http://csrc.nist.gov/encryption/aes/">http://csrc.nist.gov/encryption/aes/</a>.
*
* This implementation is based on optimizations from Dr. Brian Gladman's paper and C code at
* <a href="http://fp.gladman.plus.com/cryptography_technology/rijndael/">http://fp.gladman.plus.com/cryptography_technology/rijndael/</a>
*
* There are three levels of tradeoff of speed vs memory
* Because java has no preprocessor, they are written as three separate classes from which to choose
*
* The fastest uses 8Kbytes of static tables to precompute round calculations, 4 256 word tables for encryption
* and 4 for decryption.
*
* The middle performance version uses only one 256 word table for each, for a total of 2Kbytes,
* adding 12 rotate operations per round to compute the values contained in the other tables from
* the contents of the first
*
* The slowest version uses no static tables at all and computes the values
* in each round.
* <p>
* This file contains the slowest performance version with no static tables
* for round precomputation, but it has the smallest foot print.
*
*/
public class AESLightEngine
implements BlockCipher
{
// The S box
private static final byte[] S = {
(byte)99, (byte)124, (byte)119, (byte)123, (byte)242, (byte)107, (byte)111, (byte)197,
(byte)48, (byte)1, (byte)103, (byte)43, (byte)254, (byte)215, (byte)171, (byte)118,
(byte)202, (byte)130, (byte)201, (byte)125, (byte)250, (byte)89, (byte)71, (byte)240,
(byte)173, (byte)212, (byte)162, (byte)175, (byte)156, (byte)164, (byte)114, (byte)192,
(byte)183, (byte)253, (byte)147, (byte)38, (byte)54, (byte)63, (byte)247, (byte)204,
(byte)52, (byte)165, (byte)229, (byte)241, (byte)113, (byte)216, (byte)49, (byte)21,
(byte)4, (byte)199, (byte)35, (byte)195, (byte)24, (byte)150, (byte)5, (byte)154,
(byte)7, (byte)18, (byte)128, (byte)226, (byte)235, (byte)39, (byte)178, (byte)117,
(byte)9, (byte)131, (byte)44, (byte)26, (byte)27, (byte)110, (byte)90, (byte)160,
(byte)82, (byte)59, (byte)214, (byte)179, (byte)41, (byte)227, (byte)47, (byte)132,
(byte)83, (byte)209, (byte)0, (byte)237, (byte)32, (byte)252, (byte)177, (byte)91,
(byte)106, (byte)203, (byte)190, (byte)57, (byte)74, (byte)76, (byte)88, (byte)207,
(byte)208, (byte)239, (byte)170, (byte)251, (byte)67, (byte)77, (byte)51, (byte)133,
(byte)69, (byte)249, (byte)2, (byte)127, (byte)80, (byte)60, (byte)159, (byte)168,
(byte)81, (byte)163, (byte)64, (byte)143, (byte)146, (byte)157, (byte)56, (byte)245,
(byte)188, (byte)182, (byte)218, (byte)33, (byte)16, (byte)255, (byte)243, (byte)210,
(byte)205, (byte)12, (byte)19, (byte)236, (byte)95, (byte)151, (byte)68, (byte)23,
(byte)196, (byte)167, (byte)126, (byte)61, (byte)100, (byte)93, (byte)25, (byte)115,
(byte)96, (byte)129, (byte)79, (byte)220, (byte)34, (byte)42, (byte)144, (byte)136,
(byte)70, (byte)238, (byte)184, (byte)20, (byte)222, (byte)94, (byte)11, (byte)219,
(byte)224, (byte)50, (byte)58, (byte)10, (byte)73, (byte)6, (byte)36, (byte)92,
(byte)194, (byte)211, (byte)172, (byte)98, (byte)145, (byte)149, (byte)228, (byte)121,
(byte)231, (byte)200, (byte)55, (byte)109, (byte)141, (byte)213, (byte)78, (byte)169,
(byte)108, (byte)86, (byte)244, (byte)234, (byte)101, (byte)122, (byte)174, (byte)8,
(byte)186, (byte)120, (byte)37, (byte)46, (byte)28, (byte)166, (byte)180, (byte)198,
(byte)232, (byte)221, (byte)116, (byte)31, (byte)75, (byte)189, (byte)139, (byte)138,
(byte)112, (byte)62, (byte)181, (byte)102, (byte)72, (byte)3, (byte)246, (byte)14,
(byte)97, (byte)53, (byte)87, (byte)185, (byte)134, (byte)193, (byte)29, (byte)158,
(byte)225, (byte)248, (byte)152, (byte)17, (byte)105, (byte)217, (byte)142, (byte)148,
(byte)155, (byte)30, (byte)135, (byte)233, (byte)206, (byte)85, (byte)40, (byte)223,
(byte)140, (byte)161, (byte)137, (byte)13, (byte)191, (byte)230, (byte)66, (byte)104,
(byte)65, (byte)153, (byte)45, (byte)15, (byte)176, (byte)84, (byte)187, (byte)22,
};
// The inverse S-box
private static final byte[] Si = {
(byte)82, (byte)9, (byte)106, (byte)213, (byte)48, (byte)54, (byte)165, (byte)56,
(byte)191, (byte)64, (byte)163, (byte)158, (byte)129, (byte)243, (byte)215, (byte)251,
(byte)124, (byte)227, (byte)57, (byte)130, (byte)155, (byte)47, (byte)255, (byte)135,
(byte)52, (byte)142, (byte)67, (byte)68, (byte)196, (byte)222, (byte)233, (byte)203,
(byte)84, (byte)123, (byte)148, (byte)50, (byte)166, (byte)194, (byte)35, (byte)61,
(byte)238, (byte)76, (byte)149, (byte)11, (byte)66, (byte)250, (byte)195, (byte)78,
(byte)8, (byte)46, (byte)161, (byte)102, (byte)40, (byte)217, (byte)36, (byte)178,
(byte)118, (byte)91, (byte)162, (byte)73, (byte)109, (byte)139, (byte)209, (byte)37,
(byte)114, (byte)248, (byte)246, (byte)100, (byte)134, (byte)104, (byte)152, (byte)22,
(byte)212, (byte)164, (byte)92, (byte)204, (byte)93, (byte)101, (byte)182, (byte)146,
(byte)108, (byte)112, (byte)72, (byte)80, (byte)253, (byte)237, (byte)185, (byte)218,
(byte)94, (byte)21, (byte)70, (byte)87, (byte)167, (byte)141, (byte)157, (byte)132,
(byte)144, (byte)216, (byte)171, (byte)0, (byte)140, (byte)188, (byte)211, (byte)10,
(byte)247, (byte)228, (byte)88, (byte)5, (byte)184, (byte)179, (byte)69, (byte)6,
(byte)208, (byte)44, (byte)30, (byte)143, (byte)202, (byte)63, (byte)15, (byte)2,
(byte)193, (byte)175, (byte)189, (byte)3, (byte)1, (byte)19, (byte)138, (byte)107,
(byte)58, (byte)145, (byte)17, (byte)65, (byte)79, (byte)103, (byte)220, (byte)234,
(byte)151, (byte)242, (byte)207, (byte)206, (byte)240, (byte)180, (byte)230, (byte)115,
(byte)150, (byte)172, (byte)116, (byte)34, (byte)231, (byte)173, (byte)53, (byte)133,
(byte)226, (byte)249, (byte)55, (byte)232, (byte)28, (byte)117, (byte)223, (byte)110,
(byte)71, (byte)241, (byte)26, (byte)113, (byte)29, (byte)41, (byte)197, (byte)137,
(byte)111, (byte)183, (byte)98, (byte)14, (byte)170, (byte)24, (byte)190, (byte)27,
(byte)252, (byte)86, (byte)62, (byte)75, (byte)198, (byte)210, (byte)121, (byte)32,
(byte)154, (byte)219, (byte)192, (byte)254, (byte)120, (byte)205, (byte)90, (byte)244,
(byte)31, (byte)221, (byte)168, (byte)51, (byte)136, (byte)7, (byte)199, (byte)49,
(byte)177, (byte)18, (byte)16, (byte)89, (byte)39, (byte)128, (byte)236, (byte)95,
(byte)96, (byte)81, (byte)127, (byte)169, (byte)25, (byte)181, (byte)74, (byte)13,
(byte)45, (byte)229, (byte)122, (byte)159, (byte)147, (byte)201, (byte)156, (byte)239,
(byte)160, (byte)224, (byte)59, (byte)77, (byte)174, (byte)42, (byte)245, (byte)176,
(byte)200, (byte)235, (byte)187, (byte)60, (byte)131, (byte)83, (byte)153, (byte)97,
(byte)23, (byte)43, (byte)4, (byte)126, (byte)186, (byte)119, (byte)214, (byte)38,
(byte)225, (byte)105, (byte)20, (byte)99, (byte)85, (byte)33, (byte)12, (byte)125,
};
// vector used in calculating key schedule (powers of x in GF(256))
private static final int[] rcon = {
0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a,
0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91 };
private static int shift(int r, int shift)
{
return (r >>> shift) | (r << -shift);
}
/* multiply four bytes in GF(2^8) by 'x' {02} in parallel */
private static final int m1 = 0x80808080;
private static final int m2 = 0x7f7f7f7f;
private static final int m3 = 0x0000001b;
private static final int m4 = 0xC0C0C0C0;
private static final int m5 = 0x3f3f3f3f;
private static int FFmulX(int x)
{
return (((x & m2) << 1) ^ (((x & m1) >>> 7) * m3));
}
private static int FFmulX2(int x)
{
int t0 = (x & m5) << 2;
int t1 = (x & m4);
t1 ^= (t1 >>> 1);
return t0 ^ (t1 >>> 2) ^ (t1 >>> 5);
}
/*
The following defines provide alternative definitions of FFmulX that might
give improved performance if a fast 32-bit multiply is not available.
private int FFmulX(int x) { int u = x & m1; u |= (u >> 1); return ((x & m2) << 1) ^ ((u >>> 3) | (u >>> 6)); }
private static final int m4 = 0x1b1b1b1b;
private int FFmulX(int x) { int u = x & m1; return ((x & m2) << 1) ^ ((u - (u >>> 7)) & m4); }
*/
private static int mcol(int x)
{
int t0, t1;
t0 = shift(x, 8);
t1 = x ^ t0;
return shift(t1, 16) ^ t0 ^ FFmulX(t1);
}
private static int inv_mcol(int x)
{
int t0, t1;
t0 = x;
t1 = t0 ^ shift(t0, 8);
t0 ^= FFmulX(t1);
t1 ^= FFmulX2(t0);
t0 ^= t1 ^ shift(t1, 16);
return t0;
}
private static int subWord(int x)
{
return (S[x&255]&255 | ((S[(x>>8)&255]&255)<<8) | ((S[(x>>16)&255]&255)<<16) | S[(x>>24)&255]<<24);
}
Calculate the necessary round keys
The number of calculations depends on key size and block size
AES specified a fixed block size of 128 bits and key sizes 128/192/256 bits
This code is written assuming those are the only possible values
/**
* Calculate the necessary round keys
* The number of calculations depends on key size and block size
* AES specified a fixed block size of 128 bits and key sizes 128/192/256 bits
* This code is written assuming those are the only possible values
*/
private int[][] generateWorkingKey(byte[] key, boolean forEncryption)
{
int keyLen = key.length;
if (keyLen < 16 || keyLen > 32 || (keyLen & 7) != 0)
{
throw new IllegalArgumentException("Key length not 128/192/256 bits.");
}
int KC = keyLen >> 2;
ROUNDS = KC + 6; // This is not always true for the generalized Rijndael that allows larger block sizes
int[][] W = new int[ROUNDS+1][4]; // 4 words in a block
switch (KC)
{
case 4:
{
int t0 = Pack.littleEndianToInt(key, 0); W[0][0] = t0;
int t1 = Pack.littleEndianToInt(key, 4); W[0][1] = t1;
int t2 = Pack.littleEndianToInt(key, 8); W[0][2] = t2;
int t3 = Pack.littleEndianToInt(key, 12); W[0][3] = t3;
for (int i = 1; i <= 10; ++i)
{
int u = subWord(shift(t3, 8)) ^ rcon[i - 1];
t0 ^= u; W[i][0] = t0;
t1 ^= t0; W[i][1] = t1;
t2 ^= t1; W[i][2] = t2;
t3 ^= t2; W[i][3] = t3;
}
break;
}
case 6:
{
int t0 = Pack.littleEndianToInt(key, 0); W[0][0] = t0;
int t1 = Pack.littleEndianToInt(key, 4); W[0][1] = t1;
int t2 = Pack.littleEndianToInt(key, 8); W[0][2] = t2;
int t3 = Pack.littleEndianToInt(key, 12); W[0][3] = t3;
int t4 = Pack.littleEndianToInt(key, 16); W[1][0] = t4;
int t5 = Pack.littleEndianToInt(key, 20); W[1][1] = t5;
int rcon = 1;
int u = subWord(shift(t5, 8)) ^ rcon; rcon <<= 1;
t0 ^= u; W[1][2] = t0;
t1 ^= t0; W[1][3] = t1;
t2 ^= t1; W[2][0] = t2;
t3 ^= t2; W[2][1] = t3;
t4 ^= t3; W[2][2] = t4;
t5 ^= t4; W[2][3] = t5;
for (int i = 3; i < 12; i += 3)
{
u = subWord(shift(t5, 8)) ^ rcon; rcon <<= 1;
t0 ^= u; W[i ][0] = t0;
t1 ^= t0; W[i ][1] = t1;
t2 ^= t1; W[i ][2] = t2;
t3 ^= t2; W[i ][3] = t3;
t4 ^= t3; W[i + 1][0] = t4;
t5 ^= t4; W[i + 1][1] = t5;
u = subWord(shift(t5, 8)) ^ rcon; rcon <<= 1;
t0 ^= u; W[i + 1][2] = t0;
t1 ^= t0; W[i + 1][3] = t1;
t2 ^= t1; W[i + 2][0] = t2;
t3 ^= t2; W[i + 2][1] = t3;
t4 ^= t3; W[i + 2][2] = t4;
t5 ^= t4; W[i + 2][3] = t5;
}
u = subWord(shift(t5, 8)) ^ rcon;
t0 ^= u; W[12][0] = t0;
t1 ^= t0; W[12][1] = t1;
t2 ^= t1; W[12][2] = t2;
t3 ^= t2; W[12][3] = t3;
break;
}
case 8:
{
int t0 = Pack.littleEndianToInt(key, 0); W[0][0] = t0;
int t1 = Pack.littleEndianToInt(key, 4); W[0][1] = t1;
int t2 = Pack.littleEndianToInt(key, 8); W[0][2] = t2;
int t3 = Pack.littleEndianToInt(key, 12); W[0][3] = t3;
int t4 = Pack.littleEndianToInt(key, 16); W[1][0] = t4;
int t5 = Pack.littleEndianToInt(key, 20); W[1][1] = t5;
int t6 = Pack.littleEndianToInt(key, 24); W[1][2] = t6;
int t7 = Pack.littleEndianToInt(key, 28); W[1][3] = t7;
int u, rcon = 1;
for (int i = 2; i < 14; i += 2)
{
u = subWord(shift(t7, 8)) ^ rcon; rcon <<= 1;
t0 ^= u; W[i ][0] = t0;
t1 ^= t0; W[i ][1] = t1;
t2 ^= t1; W[i ][2] = t2;
t3 ^= t2; W[i ][3] = t3;
u = subWord(t3);
t4 ^= u; W[i + 1][0] = t4;
t5 ^= t4; W[i + 1][1] = t5;
t6 ^= t5; W[i + 1][2] = t6;
t7 ^= t6; W[i + 1][3] = t7;
}
u = subWord(shift(t7, 8)) ^ rcon;
t0 ^= u; W[14][0] = t0;
t1 ^= t0; W[14][1] = t1;
t2 ^= t1; W[14][2] = t2;
t3 ^= t2; W[14][3] = t3;
break;
}
default:
{
throw new IllegalStateException("Should never get here");
}
}
if (!forEncryption)
{
for (int j = 1; j < ROUNDS; j++)
{
for (int i = 0; i < 4; i++)
{
W[j][i] = inv_mcol(W[j][i]);
}
}
}
return W;
}
private int ROUNDS;
private int[][] WorkingKey = null;
private int C0, C1, C2, C3;
private boolean forEncryption;
private static final int BLOCK_SIZE = 16;
default constructor - 128 bit block size.
/**
* default constructor - 128 bit block size.
*/
public AESLightEngine()
{
}
initialise an AES cipher.
Params: - forEncryption – whether or not we are for encryption.
- params – the parameters required to set up the cipher.
Throws: - IllegalArgumentException – if the params argument is
inappropriate.
/**
* initialise an AES cipher.
*
* @param forEncryption whether or not we are for encryption.
* @param params the parameters required to set up the cipher.
* @exception IllegalArgumentException if the params argument is
* inappropriate.
*/
public void init(
boolean forEncryption,
CipherParameters params)
{
if (params instanceof KeyParameter)
{
WorkingKey = generateWorkingKey(((KeyParameter)params).getKey(), forEncryption);
this.forEncryption = forEncryption;
return;
}
throw new IllegalArgumentException("invalid parameter passed to AES init - " + params.getClass().getName());
}
public String getAlgorithmName()
{
return "AES";
}
public int getBlockSize()
{
return BLOCK_SIZE;
}
public int processBlock(
byte[] in,
int inOff,
byte[] out,
int outOff)
{
if (WorkingKey == null)
{
throw new IllegalStateException("AES engine not initialised");
}
if ((inOff + (32 / 2)) > in.length)
{
throw new DataLengthException("input buffer too short");
}
if ((outOff + (32 / 2)) > out.length)
{
throw new OutputLengthException("output buffer too short");
}
if (forEncryption)
{
unpackBlock(in, inOff);
encryptBlock(WorkingKey);
packBlock(out, outOff);
}
else
{
unpackBlock(in, inOff);
decryptBlock(WorkingKey);
packBlock(out, outOff);
}
return BLOCK_SIZE;
}
public void reset()
{
}
private void unpackBlock(
byte[] bytes,
int off)
{
int index = off;
C0 = (bytes[index++] & 0xff);
C0 |= (bytes[index++] & 0xff) << 8;
C0 |= (bytes[index++] & 0xff) << 16;
C0 |= bytes[index++] << 24;
C1 = (bytes[index++] & 0xff);
C1 |= (bytes[index++] & 0xff) << 8;
C1 |= (bytes[index++] & 0xff) << 16;
C1 |= bytes[index++] << 24;
C2 = (bytes[index++] & 0xff);
C2 |= (bytes[index++] & 0xff) << 8;
C2 |= (bytes[index++] & 0xff) << 16;
C2 |= bytes[index++] << 24;
C3 = (bytes[index++] & 0xff);
C3 |= (bytes[index++] & 0xff) << 8;
C3 |= (bytes[index++] & 0xff) << 16;
C3 |= bytes[index++] << 24;
}
private void packBlock(
byte[] bytes,
int off)
{
int index = off;
bytes[index++] = (byte)C0;
bytes[index++] = (byte)(C0 >> 8);
bytes[index++] = (byte)(C0 >> 16);
bytes[index++] = (byte)(C0 >> 24);
bytes[index++] = (byte)C1;
bytes[index++] = (byte)(C1 >> 8);
bytes[index++] = (byte)(C1 >> 16);
bytes[index++] = (byte)(C1 >> 24);
bytes[index++] = (byte)C2;
bytes[index++] = (byte)(C2 >> 8);
bytes[index++] = (byte)(C2 >> 16);
bytes[index++] = (byte)(C2 >> 24);
bytes[index++] = (byte)C3;
bytes[index++] = (byte)(C3 >> 8);
bytes[index++] = (byte)(C3 >> 16);
bytes[index++] = (byte)(C3 >> 24);
}
private void encryptBlock(int[][] KW)
{
int t0 = this.C0 ^ KW[0][0];
int t1 = this.C1 ^ KW[0][1];
int t2 = this.C2 ^ KW[0][2];
int r = 1, r0, r1, r2, r3 = this.C3 ^ KW[0][3];
while (r < ROUNDS - 1)
{
r0 = mcol((S[t0&255]&255) ^ ((S[(t1>>8)&255]&255)<<8) ^ ((S[(t2>>16)&255]&255)<<16) ^ (S[(r3>>24)&255]<<24)) ^ KW[r][0];
r1 = mcol((S[t1&255]&255) ^ ((S[(t2>>8)&255]&255)<<8) ^ ((S[(r3>>16)&255]&255)<<16) ^ (S[(t0>>24)&255]<<24)) ^ KW[r][1];
r2 = mcol((S[t2&255]&255) ^ ((S[(r3>>8)&255]&255)<<8) ^ ((S[(t0>>16)&255]&255)<<16) ^ (S[(t1>>24)&255]<<24)) ^ KW[r][2];
r3 = mcol((S[r3&255]&255) ^ ((S[(t0>>8)&255]&255)<<8) ^ ((S[(t1>>16)&255]&255)<<16) ^ (S[(t2>>24)&255]<<24)) ^ KW[r++][3];
t0 = mcol((S[r0&255]&255) ^ ((S[(r1>>8)&255]&255)<<8) ^ ((S[(r2>>16)&255]&255)<<16) ^ (S[(r3>>24)&255]<<24)) ^ KW[r][0];
t1 = mcol((S[r1&255]&255) ^ ((S[(r2>>8)&255]&255)<<8) ^ ((S[(r3>>16)&255]&255)<<16) ^ (S[(r0>>24)&255]<<24)) ^ KW[r][1];
t2 = mcol((S[r2&255]&255) ^ ((S[(r3>>8)&255]&255)<<8) ^ ((S[(r0>>16)&255]&255)<<16) ^ (S[(r1>>24)&255]<<24)) ^ KW[r][2];
r3 = mcol((S[r3&255]&255) ^ ((S[(r0>>8)&255]&255)<<8) ^ ((S[(r1>>16)&255]&255)<<16) ^ (S[(r2>>24)&255]<<24)) ^ KW[r++][3];
}
r0 = mcol((S[t0&255]&255) ^ ((S[(t1>>8)&255]&255)<<8) ^ ((S[(t2>>16)&255]&255)<<16) ^ (S[(r3>>24)&255]<<24)) ^ KW[r][0];
r1 = mcol((S[t1&255]&255) ^ ((S[(t2>>8)&255]&255)<<8) ^ ((S[(r3>>16)&255]&255)<<16) ^ (S[(t0>>24)&255]<<24)) ^ KW[r][1];
r2 = mcol((S[t2&255]&255) ^ ((S[(r3>>8)&255]&255)<<8) ^ ((S[(t0>>16)&255]&255)<<16) ^ (S[(t1>>24)&255]<<24)) ^ KW[r][2];
r3 = mcol((S[r3&255]&255) ^ ((S[(t0>>8)&255]&255)<<8) ^ ((S[(t1>>16)&255]&255)<<16) ^ (S[(t2>>24)&255]<<24)) ^ KW[r++][3];
// the final round is a simple function of S
this.C0 = (S[r0&255]&255) ^ ((S[(r1>>8)&255]&255)<<8) ^ ((S[(r2>>16)&255]&255)<<16) ^ (S[(r3>>24)&255]<<24) ^ KW[r][0];
this.C1 = (S[r1&255]&255) ^ ((S[(r2>>8)&255]&255)<<8) ^ ((S[(r3>>16)&255]&255)<<16) ^ (S[(r0>>24)&255]<<24) ^ KW[r][1];
this.C2 = (S[r2&255]&255) ^ ((S[(r3>>8)&255]&255)<<8) ^ ((S[(r0>>16)&255]&255)<<16) ^ (S[(r1>>24)&255]<<24) ^ KW[r][2];
this.C3 = (S[r3&255]&255) ^ ((S[(r0>>8)&255]&255)<<8) ^ ((S[(r1>>16)&255]&255)<<16) ^ (S[(r2>>24)&255]<<24) ^ KW[r][3];
}
private void decryptBlock(int[][] KW)
{
int t0 = this.C0 ^ KW[ROUNDS][0];
int t1 = this.C1 ^ KW[ROUNDS][1];
int t2 = this.C2 ^ KW[ROUNDS][2];
int r = ROUNDS - 1, r0, r1, r2, r3 = this.C3 ^ KW[ROUNDS][3];
while (r > 1)
{
r0 = inv_mcol((Si[t0&255]&255) ^ ((Si[(r3>>8)&255]&255)<<8) ^ ((Si[(t2>>16)&255]&255)<<16) ^ (Si[(t1>>24)&255]<<24)) ^ KW[r][0];
r1 = inv_mcol((Si[t1&255]&255) ^ ((Si[(t0>>8)&255]&255)<<8) ^ ((Si[(r3>>16)&255]&255)<<16) ^ (Si[(t2>>24)&255]<<24)) ^ KW[r][1];
r2 = inv_mcol((Si[t2&255]&255) ^ ((Si[(t1>>8)&255]&255)<<8) ^ ((Si[(t0>>16)&255]&255)<<16) ^ (Si[(r3>>24)&255]<<24)) ^ KW[r][2];
r3 = inv_mcol((Si[r3&255]&255) ^ ((Si[(t2>>8)&255]&255)<<8) ^ ((Si[(t1>>16)&255]&255)<<16) ^ (Si[(t0>>24)&255]<<24)) ^ KW[r--][3];
t0 = inv_mcol((Si[r0&255]&255) ^ ((Si[(r3>>8)&255]&255)<<8) ^ ((Si[(r2>>16)&255]&255)<<16) ^ (Si[(r1>>24)&255]<<24)) ^ KW[r][0];
t1 = inv_mcol((Si[r1&255]&255) ^ ((Si[(r0>>8)&255]&255)<<8) ^ ((Si[(r3>>16)&255]&255)<<16) ^ (Si[(r2>>24)&255]<<24)) ^ KW[r][1];
t2 = inv_mcol((Si[r2&255]&255) ^ ((Si[(r1>>8)&255]&255)<<8) ^ ((Si[(r0>>16)&255]&255)<<16) ^ (Si[(r3>>24)&255]<<24)) ^ KW[r][2];
r3 = inv_mcol((Si[r3&255]&255) ^ ((Si[(r2>>8)&255]&255)<<8) ^ ((Si[(r1>>16)&255]&255)<<16) ^ (Si[(r0>>24)&255]<<24)) ^ KW[r--][3];
}
r0 = inv_mcol((Si[t0&255]&255) ^ ((Si[(r3>>8)&255]&255)<<8) ^ ((Si[(t2>>16)&255]&255)<<16) ^ (Si[(t1>>24)&255]<<24)) ^ KW[r][0];
r1 = inv_mcol((Si[t1&255]&255) ^ ((Si[(t0>>8)&255]&255)<<8) ^ ((Si[(r3>>16)&255]&255)<<16) ^ (Si[(t2>>24)&255]<<24)) ^ KW[r][1];
r2 = inv_mcol((Si[t2&255]&255) ^ ((Si[(t1>>8)&255]&255)<<8) ^ ((Si[(t0>>16)&255]&255)<<16) ^ (Si[(r3>>24)&255]<<24)) ^ KW[r][2];
r3 = inv_mcol((Si[r3&255]&255) ^ ((Si[(t2>>8)&255]&255)<<8) ^ ((Si[(t1>>16)&255]&255)<<16) ^ (Si[(t0>>24)&255]<<24)) ^ KW[r][3];
// the final round's table is a simple function of Si
this.C0 = (Si[r0&255]&255) ^ ((Si[(r3>>8)&255]&255)<<8) ^ ((Si[(r2>>16)&255]&255)<<16) ^ (Si[(r1>>24)&255]<<24) ^ KW[0][0];
this.C1 = (Si[r1&255]&255) ^ ((Si[(r0>>8)&255]&255)<<8) ^ ((Si[(r3>>16)&255]&255)<<16) ^ (Si[(r2>>24)&255]<<24) ^ KW[0][1];
this.C2 = (Si[r2&255]&255) ^ ((Si[(r1>>8)&255]&255)<<8) ^ ((Si[(r0>>16)&255]&255)<<16) ^ (Si[(r3>>24)&255]<<24) ^ KW[0][2];
this.C3 = (Si[r3&255]&255) ^ ((Si[(r2>>8)&255]&255)<<8) ^ ((Si[(r1>>16)&255]&255)<<16) ^ (Si[(r0>>24)&255]<<24) ^ KW[0][3];
}
}