439 lines
21 KiB
C#
439 lines
21 KiB
C#
using System;
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using Org.BouncyCastle.Crypto.Parameters;
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namespace Org.BouncyCastle.Crypto.Engines
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{
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/**
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* an implementation of the AES (Rijndael), from FIPS-197.
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* <p>
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* For further details see: <a href="http://csrc.nist.gov/encryption/aes/">http://csrc.nist.gov/encryption/aes/</a>.
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*
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* This implementation is based on optimizations from Dr. Brian Gladman's paper and C code at
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* <a href="http://fp.gladman.plus.com/cryptography_technology/rijndael/">http://fp.gladman.plus.com/cryptography_technology/rijndael/</a>
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*
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* There are three levels of tradeoff of speed vs memory
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* Because java has no preprocessor, they are written as three separate classes from which to choose
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*
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* The fastest uses 8Kbytes of static tables to precompute round calculations, 4 256 word tables for encryption
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* and 4 for decryption.
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*
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* The middle performance version uses only one 256 word table for each, for a total of 2Kbytes,
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* adding 12 rotate operations per round to compute the values contained in the other tables from
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* the contents of the first
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*
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* The slowest version uses no static tables at all and computes the values
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* in each round.
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* </p>
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* <p>
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* This file contains the slowest performance version with no static tables
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* for round precomputation, but it has the smallest foot print.
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* </p>
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*/
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public class AesLightEngine
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: IBlockCipher
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{
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// The S box
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private static readonly byte[] S = {
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(byte)99, (byte)124, (byte)119, (byte)123, (byte)242, (byte)107, (byte)111, (byte)197,
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(byte)48, (byte)1, (byte)103, (byte)43, (byte)254, (byte)215, (byte)171, (byte)118,
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(byte)202, (byte)130, (byte)201, (byte)125, (byte)250, (byte)89, (byte)71, (byte)240,
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(byte)173, (byte)212, (byte)162, (byte)175, (byte)156, (byte)164, (byte)114, (byte)192,
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(byte)183, (byte)253, (byte)147, (byte)38, (byte)54, (byte)63, (byte)247, (byte)204,
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(byte)52, (byte)165, (byte)229, (byte)241, (byte)113, (byte)216, (byte)49, (byte)21,
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(byte)4, (byte)199, (byte)35, (byte)195, (byte)24, (byte)150, (byte)5, (byte)154,
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(byte)7, (byte)18, (byte)128, (byte)226, (byte)235, (byte)39, (byte)178, (byte)117,
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(byte)9, (byte)131, (byte)44, (byte)26, (byte)27, (byte)110, (byte)90, (byte)160,
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(byte)82, (byte)59, (byte)214, (byte)179, (byte)41, (byte)227, (byte)47, (byte)132,
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(byte)83, (byte)209, (byte)0, (byte)237, (byte)32, (byte)252, (byte)177, (byte)91,
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(byte)106, (byte)203, (byte)190, (byte)57, (byte)74, (byte)76, (byte)88, (byte)207,
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(byte)208, (byte)239, (byte)170, (byte)251, (byte)67, (byte)77, (byte)51, (byte)133,
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(byte)69, (byte)249, (byte)2, (byte)127, (byte)80, (byte)60, (byte)159, (byte)168,
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(byte)81, (byte)163, (byte)64, (byte)143, (byte)146, (byte)157, (byte)56, (byte)245,
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(byte)188, (byte)182, (byte)218, (byte)33, (byte)16, (byte)255, (byte)243, (byte)210,
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(byte)205, (byte)12, (byte)19, (byte)236, (byte)95, (byte)151, (byte)68, (byte)23,
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(byte)196, (byte)167, (byte)126, (byte)61, (byte)100, (byte)93, (byte)25, (byte)115,
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(byte)96, (byte)129, (byte)79, (byte)220, (byte)34, (byte)42, (byte)144, (byte)136,
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(byte)70, (byte)238, (byte)184, (byte)20, (byte)222, (byte)94, (byte)11, (byte)219,
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(byte)224, (byte)50, (byte)58, (byte)10, (byte)73, (byte)6, (byte)36, (byte)92,
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(byte)194, (byte)211, (byte)172, (byte)98, (byte)145, (byte)149, (byte)228, (byte)121,
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(byte)231, (byte)200, (byte)55, (byte)109, (byte)141, (byte)213, (byte)78, (byte)169,
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(byte)108, (byte)86, (byte)244, (byte)234, (byte)101, (byte)122, (byte)174, (byte)8,
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(byte)186, (byte)120, (byte)37, (byte)46, (byte)28, (byte)166, (byte)180, (byte)198,
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(byte)232, (byte)221, (byte)116, (byte)31, (byte)75, (byte)189, (byte)139, (byte)138,
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(byte)112, (byte)62, (byte)181, (byte)102, (byte)72, (byte)3, (byte)246, (byte)14,
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(byte)97, (byte)53, (byte)87, (byte)185, (byte)134, (byte)193, (byte)29, (byte)158,
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(byte)225, (byte)248, (byte)152, (byte)17, (byte)105, (byte)217, (byte)142, (byte)148,
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(byte)155, (byte)30, (byte)135, (byte)233, (byte)206, (byte)85, (byte)40, (byte)223,
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(byte)140, (byte)161, (byte)137, (byte)13, (byte)191, (byte)230, (byte)66, (byte)104,
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(byte)65, (byte)153, (byte)45, (byte)15, (byte)176, (byte)84, (byte)187, (byte)22,
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};
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// The inverse S-box
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private static readonly byte[] Si = {
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(byte)82, (byte)9, (byte)106, (byte)213, (byte)48, (byte)54, (byte)165, (byte)56,
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(byte)191, (byte)64, (byte)163, (byte)158, (byte)129, (byte)243, (byte)215, (byte)251,
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(byte)124, (byte)227, (byte)57, (byte)130, (byte)155, (byte)47, (byte)255, (byte)135,
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(byte)52, (byte)142, (byte)67, (byte)68, (byte)196, (byte)222, (byte)233, (byte)203,
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(byte)84, (byte)123, (byte)148, (byte)50, (byte)166, (byte)194, (byte)35, (byte)61,
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(byte)238, (byte)76, (byte)149, (byte)11, (byte)66, (byte)250, (byte)195, (byte)78,
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(byte)8, (byte)46, (byte)161, (byte)102, (byte)40, (byte)217, (byte)36, (byte)178,
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(byte)118, (byte)91, (byte)162, (byte)73, (byte)109, (byte)139, (byte)209, (byte)37,
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(byte)114, (byte)248, (byte)246, (byte)100, (byte)134, (byte)104, (byte)152, (byte)22,
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(byte)212, (byte)164, (byte)92, (byte)204, (byte)93, (byte)101, (byte)182, (byte)146,
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(byte)108, (byte)112, (byte)72, (byte)80, (byte)253, (byte)237, (byte)185, (byte)218,
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(byte)94, (byte)21, (byte)70, (byte)87, (byte)167, (byte)141, (byte)157, (byte)132,
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(byte)144, (byte)216, (byte)171, (byte)0, (byte)140, (byte)188, (byte)211, (byte)10,
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(byte)247, (byte)228, (byte)88, (byte)5, (byte)184, (byte)179, (byte)69, (byte)6,
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(byte)208, (byte)44, (byte)30, (byte)143, (byte)202, (byte)63, (byte)15, (byte)2,
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(byte)193, (byte)175, (byte)189, (byte)3, (byte)1, (byte)19, (byte)138, (byte)107,
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(byte)58, (byte)145, (byte)17, (byte)65, (byte)79, (byte)103, (byte)220, (byte)234,
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(byte)151, (byte)242, (byte)207, (byte)206, (byte)240, (byte)180, (byte)230, (byte)115,
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(byte)150, (byte)172, (byte)116, (byte)34, (byte)231, (byte)173, (byte)53, (byte)133,
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(byte)226, (byte)249, (byte)55, (byte)232, (byte)28, (byte)117, (byte)223, (byte)110,
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(byte)71, (byte)241, (byte)26, (byte)113, (byte)29, (byte)41, (byte)197, (byte)137,
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(byte)111, (byte)183, (byte)98, (byte)14, (byte)170, (byte)24, (byte)190, (byte)27,
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(byte)252, (byte)86, (byte)62, (byte)75, (byte)198, (byte)210, (byte)121, (byte)32,
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(byte)154, (byte)219, (byte)192, (byte)254, (byte)120, (byte)205, (byte)90, (byte)244,
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(byte)31, (byte)221, (byte)168, (byte)51, (byte)136, (byte)7, (byte)199, (byte)49,
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(byte)177, (byte)18, (byte)16, (byte)89, (byte)39, (byte)128, (byte)236, (byte)95,
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(byte)96, (byte)81, (byte)127, (byte)169, (byte)25, (byte)181, (byte)74, (byte)13,
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(byte)45, (byte)229, (byte)122, (byte)159, (byte)147, (byte)201, (byte)156, (byte)239,
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(byte)160, (byte)224, (byte)59, (byte)77, (byte)174, (byte)42, (byte)245, (byte)176,
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(byte)200, (byte)235, (byte)187, (byte)60, (byte)131, (byte)83, (byte)153, (byte)97,
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(byte)23, (byte)43, (byte)4, (byte)126, (byte)186, (byte)119, (byte)214, (byte)38,
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(byte)225, (byte)105, (byte)20, (byte)99, (byte)85, (byte)33, (byte)12, (byte)125,
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};
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// vector used in calculating key schedule (powers of x in GF(256))
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private static readonly int[] rcon = {
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0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a,
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0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91 };
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private int Shift(
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int r,
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int shift)
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{
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return ((int) ( ( (uint) r >> shift) |
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(uint) (r << (32 - shift)) )
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);
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}
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/* multiply four bytes in GF(2^8) by 'x' {02} in parallel */
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private const int m1 = unchecked((int) 0x80808080);
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private const int m2 = unchecked((int) 0x7f7f7f7f);
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private const int m3 = unchecked((int) 0x0000001b);
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private int FFmulX(int x)
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{
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return ( (int) ( ((x & m2) << 1) ^
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(( (uint)(x & m1) >> 7) * m3)
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)
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);
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}
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/*
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The following defines provide alternative definitions of FFmulX that might
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give improved performance if a fast 32-bit multiply is not available.
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private int FFmulX(int x) { int u = x & m1; u |= (u >> 1); return ((x & m2) << 1) ^ ((u >>> 3) | (u >>> 6)); }
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private static final int m4 = 0x1b1b1b1b;
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private int FFmulX(int x) { int u = x & m1; return ((x & m2) << 1) ^ ((u - (u >>> 7)) & m4); }
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*/
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private int Mcol(int x)
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{
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int f2 = FFmulX(x);
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return f2 ^ Shift(x ^ f2, 8) ^ Shift(x, 16) ^ Shift(x, 24);
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}
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private int Inv_Mcol(int x)
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{
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int f2 = FFmulX(x);
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int f4 = FFmulX(f2);
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int f8 = FFmulX(f4);
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int f9 = x ^ f8;
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return f2 ^ f4 ^ f8 ^ Shift(f2 ^ f9, 8) ^ Shift(f4 ^ f9, 16) ^ Shift(f9, 24);
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}
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private int SubWord(int x)
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{
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return (S[x&255]&255 | ((S[(x>>8)&255]&255)<<8) | ((S[(x>>16)&255]&255)<<16) | S[(x>>24)&255]<<24);
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}
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/**
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* Calculate the necessary round keys
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* The number of calculations depends on key size and block size
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* AES specified a fixed block size of 128 bits and key sizes 128/192/256 bits
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* This code is written assuming those are the only possible values
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*/
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private int[,] GenerateWorkingKey(
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byte[] key,
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bool forEncryption)
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{
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int KC = key.Length / 4; // key length in words
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int t;
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if ((KC != 4) && (KC != 6) && (KC != 8)) {
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throw new ArgumentException("Key length not 128/192/256 bits.");
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}
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ROUNDS = KC + 6; // This is not always true for the generalized Rijndael that allows larger block sizes
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int[,] W = new int[ROUNDS+1,4]; // 4 words in a block
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//
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// copy the key into the round key array
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//
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t = 0;
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for (int i = 0; i < key.Length; t++)
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{
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W[t >> 2,t & 3] = (key[i]&0xff) | ((key[i+1]&0xff) << 8) | ((key[i+2]&0xff) << 16) | (key[i+3] << 24);
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i+=4;
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}
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//
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// while not enough round key material calculated
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// calculate new values
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//
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int k = (ROUNDS + 1) << 2;
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for (int i = KC; (i < k); i++)
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{
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int temp = W[(i-1)>>2,(i-1)&3];
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if ((i % KC) == 0) {
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temp = SubWord(Shift(temp, 8)) ^ rcon[(i / KC)-1];
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} else if ((KC > 6) && ((i % KC) == 4)) {
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temp = SubWord(temp);
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}
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W[i>>2,i&3] = W[(i - KC)>>2,(i-KC)&3] ^ temp;
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}
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if (!forEncryption) {
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for (int j = 1; j < ROUNDS; j++) {
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for (int i = 0; i < 4; i++){
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W[j,i] = Inv_Mcol(W[j,i]);
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}
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}
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}
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return W;
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}
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private int ROUNDS;
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private int[,] WorkingKey;
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private int C0, C1, C2, C3;
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private bool forEncryption;
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private const int BLOCK_SIZE = 16;
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/**
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* default constructor - 128 bit block size.
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*/
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public AesLightEngine()
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{
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}
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/**
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* initialise an AES cipher.
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*
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* @param forEncryption whether or not we are for encryption.
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* @param parameters the parameters required to set up the cipher.
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* @exception ArgumentException if the parameters argument is
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* inappropriate.
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*/
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public void Init(
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bool forEncryption,
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ICipherParameters parameters)
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{
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if (!(parameters is KeyParameter))
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throw new ArgumentException("invalid parameter passed to AES init - " + parameters.GetType().ToString());
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WorkingKey = GenerateWorkingKey(((KeyParameter)parameters).GetKey(), forEncryption);
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this.forEncryption = forEncryption;
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}
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public string AlgorithmName
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{
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get { return "AES"; }
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}
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public bool IsPartialBlockOkay
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{
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get { return false; }
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}
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public int GetBlockSize()
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{
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return BLOCK_SIZE;
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}
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public int ProcessBlock(
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byte[] input,
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int inOff,
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byte[] output,
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int outOff)
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{
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if (WorkingKey == null)
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{
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throw new InvalidOperationException("AES engine not initialised");
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}
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if ((inOff + (32 / 2)) > input.Length)
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{
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throw new DataLengthException("input buffer too short");
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}
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if ((outOff + (32 / 2)) > output.Length)
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{
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throw new DataLengthException("output buffer too short");
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}
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if (forEncryption)
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{
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UnPackBlock(input, inOff);
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EncryptBlock(WorkingKey);
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PackBlock(output, outOff);
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}
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else
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{
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UnPackBlock(input, inOff);
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DecryptBlock(WorkingKey);
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PackBlock(output, outOff);
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}
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return BLOCK_SIZE;
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}
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public void Reset()
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{
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}
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private void UnPackBlock(
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byte[] bytes,
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int off)
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{
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int index = off;
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C0 = (bytes[index++] & 0xff);
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C0 |= (bytes[index++] & 0xff) << 8;
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C0 |= (bytes[index++] & 0xff) << 16;
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C0 |= bytes[index++] << 24;
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C1 = (bytes[index++] & 0xff);
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C1 |= (bytes[index++] & 0xff) << 8;
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C1 |= (bytes[index++] & 0xff) << 16;
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C1 |= bytes[index++] << 24;
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C2 = (bytes[index++] & 0xff);
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C2 |= (bytes[index++] & 0xff) << 8;
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C2 |= (bytes[index++] & 0xff) << 16;
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C2 |= bytes[index++] << 24;
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C3 = (bytes[index++] & 0xff);
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C3 |= (bytes[index++] & 0xff) << 8;
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C3 |= (bytes[index++] & 0xff) << 16;
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C3 |= bytes[index++] << 24;
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}
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private void PackBlock(
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byte[] bytes,
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int off)
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{
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int index = off;
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bytes[index++] = (byte)C0;
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bytes[index++] = (byte)(C0 >> 8);
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bytes[index++] = (byte)(C0 >> 16);
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bytes[index++] = (byte)(C0 >> 24);
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bytes[index++] = (byte)C1;
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bytes[index++] = (byte)(C1 >> 8);
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bytes[index++] = (byte)(C1 >> 16);
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bytes[index++] = (byte)(C1 >> 24);
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bytes[index++] = (byte)C2;
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bytes[index++] = (byte)(C2 >> 8);
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bytes[index++] = (byte)(C2 >> 16);
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bytes[index++] = (byte)(C2 >> 24);
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bytes[index++] = (byte)C3;
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bytes[index++] = (byte)(C3 >> 8);
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bytes[index++] = (byte)(C3 >> 16);
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bytes[index++] = (byte)(C3 >> 24);
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}
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private void EncryptBlock(int[,] KW)
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{
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int r, r0, r1, r2, r3;
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C0 ^= KW[0,0];
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C1 ^= KW[0,1];
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C2 ^= KW[0,2];
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C3 ^= KW[0,3];
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for (r = 1; r < ROUNDS - 1;) {
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r0 = Mcol((S[C0&255]&255) ^ ((S[(C1>>8)&255]&255)<<8) ^ ((S[(C2>>16)&255]&255)<<16) ^ (S[(C3>>24)&255]<<24)) ^ KW[r,0];
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r1 = Mcol((S[C1&255]&255) ^ ((S[(C2>>8)&255]&255)<<8) ^ ((S[(C3>>16)&255]&255)<<16) ^ (S[(C0>>24)&255]<<24)) ^ KW[r,1];
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r2 = Mcol((S[C2&255]&255) ^ ((S[(C3>>8)&255]&255)<<8) ^ ((S[(C0>>16)&255]&255)<<16) ^ (S[(C1>>24)&255]<<24)) ^ KW[r,2];
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r3 = Mcol((S[C3&255]&255) ^ ((S[(C0>>8)&255]&255)<<8) ^ ((S[(C1>>16)&255]&255)<<16) ^ (S[(C2>>24)&255]<<24)) ^ KW[r++,3];
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C0 = 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];
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C1 = 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];
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C2 = 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];
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C3 = 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];
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}
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r0 = Mcol((S[C0&255]&255) ^ ((S[(C1>>8)&255]&255)<<8) ^ ((S[(C2>>16)&255]&255)<<16) ^ (S[(C3>>24)&255]<<24)) ^ KW[r,0];
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r1 = Mcol((S[C1&255]&255) ^ ((S[(C2>>8)&255]&255)<<8) ^ ((S[(C3>>16)&255]&255)<<16) ^ (S[(C0>>24)&255]<<24)) ^ KW[r,1];
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r2 = Mcol((S[C2&255]&255) ^ ((S[(C3>>8)&255]&255)<<8) ^ ((S[(C0>>16)&255]&255)<<16) ^ (S[(C1>>24)&255]<<24)) ^ KW[r,2];
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r3 = Mcol((S[C3&255]&255) ^ ((S[(C0>>8)&255]&255)<<8) ^ ((S[(C1>>16)&255]&255)<<16) ^ (S[(C2>>24)&255]<<24)) ^ KW[r++,3];
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// the final round is a simple function of S
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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];
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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];
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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];
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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];
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}
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private void DecryptBlock(int[,] KW)
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{
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int r, r0, r1, r2, r3;
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C0 ^= KW[ROUNDS,0];
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C1 ^= KW[ROUNDS,1];
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C2 ^= KW[ROUNDS,2];
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C3 ^= KW[ROUNDS,3];
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for (r = ROUNDS-1; r>1;) {
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r0 = Inv_Mcol((Si[C0&255]&255) ^ ((Si[(C3>>8)&255]&255)<<8) ^ ((Si[(C2>>16)&255]&255)<<16) ^ (Si[(C1>>24)&255]<<24)) ^ KW[r,0];
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r1 = Inv_Mcol((Si[C1&255]&255) ^ ((Si[(C0>>8)&255]&255)<<8) ^ ((Si[(C3>>16)&255]&255)<<16) ^ (Si[(C2>>24)&255]<<24)) ^ KW[r,1];
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r2 = Inv_Mcol((Si[C2&255]&255) ^ ((Si[(C1>>8)&255]&255)<<8) ^ ((Si[(C0>>16)&255]&255)<<16) ^ (Si[(C3>>24)&255]<<24)) ^ KW[r,2];
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r3 = Inv_Mcol((Si[C3&255]&255) ^ ((Si[(C2>>8)&255]&255)<<8) ^ ((Si[(C1>>16)&255]&255)<<16) ^ (Si[(C0>>24)&255]<<24)) ^ KW[r--,3];
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C0 = 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];
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C1 = 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];
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C2 = 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];
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C3 = 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];
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}
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r0 = Inv_Mcol((Si[C0&255]&255) ^ ((Si[(C3>>8)&255]&255)<<8) ^ ((Si[(C2>>16)&255]&255)<<16) ^ (Si[(C1>>24)&255]<<24)) ^ KW[r,0];
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r1 = Inv_Mcol((Si[C1&255]&255) ^ ((Si[(C0>>8)&255]&255)<<8) ^ ((Si[(C3>>16)&255]&255)<<16) ^ (Si[(C2>>24)&255]<<24)) ^ KW[r,1];
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r2 = Inv_Mcol((Si[C2&255]&255) ^ ((Si[(C1>>8)&255]&255)<<8) ^ ((Si[(C0>>16)&255]&255)<<16) ^ (Si[(C3>>24)&255]<<24)) ^ KW[r,2];
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r3 = Inv_Mcol((Si[C3&255]&255) ^ ((Si[(C2>>8)&255]&255)<<8) ^ ((Si[(C1>>16)&255]&255)<<16) ^ (Si[(C0>>24)&255]<<24)) ^ KW[r,3];
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// the final round's table is a simple function of Si
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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];
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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];
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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];
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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];
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}
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}
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}
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