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skipjack.cpp

00001 // skipjack.cpp - modified by Wei Dai from Paulo Barreto's skipjack32.c, 00002 // which is public domain according to his web site. 00003 00004 #include "pch.h" 00005 00006 #ifndef CRYPTOPP_IMPORTS 00007 00008 #include "skipjack.h" 00009 00010 /* 00011 * Optimized implementation of SKIPJACK algorithm 00012 * 00013 * originally written by Panu Rissanen <bande@lut.fi> 1998.06.24 00014 * optimized by Mark Tillotson <markt@chaos.org.uk> 1998.06.25 00015 * optimized by Paulo Barreto <pbarreto@nw.com.br> 1998.06.30 00016 */ 00017 00018 NAMESPACE_BEGIN(CryptoPP) 00019 00020 /** 00021 * The F-table byte permutation (see description of the G-box permutation) 00022 */ 00023 const byte SKIPJACK::Base::fTable[256] = { 00024 0xa3,0xd7,0x09,0x83,0xf8,0x48,0xf6,0xf4,0xb3,0x21,0x15,0x78,0x99,0xb1,0xaf,0xf9, 00025 0xe7,0x2d,0x4d,0x8a,0xce,0x4c,0xca,0x2e,0x52,0x95,0xd9,0x1e,0x4e,0x38,0x44,0x28, 00026 0x0a,0xdf,0x02,0xa0,0x17,0xf1,0x60,0x68,0x12,0xb7,0x7a,0xc3,0xe9,0xfa,0x3d,0x53, 00027 0x96,0x84,0x6b,0xba,0xf2,0x63,0x9a,0x19,0x7c,0xae,0xe5,0xf5,0xf7,0x16,0x6a,0xa2, 00028 0x39,0xb6,0x7b,0x0f,0xc1,0x93,0x81,0x1b,0xee,0xb4,0x1a,0xea,0xd0,0x91,0x2f,0xb8, 00029 0x55,0xb9,0xda,0x85,0x3f,0x41,0xbf,0xe0,0x5a,0x58,0x80,0x5f,0x66,0x0b,0xd8,0x90, 00030 0x35,0xd5,0xc0,0xa7,0x33,0x06,0x65,0x69,0x45,0x00,0x94,0x56,0x6d,0x98,0x9b,0x76, 00031 0x97,0xfc,0xb2,0xc2,0xb0,0xfe,0xdb,0x20,0xe1,0xeb,0xd6,0xe4,0xdd,0x47,0x4a,0x1d, 00032 0x42,0xed,0x9e,0x6e,0x49,0x3c,0xcd,0x43,0x27,0xd2,0x07,0xd4,0xde,0xc7,0x67,0x18, 00033 0x89,0xcb,0x30,0x1f,0x8d,0xc6,0x8f,0xaa,0xc8,0x74,0xdc,0xc9,0x5d,0x5c,0x31,0xa4, 00034 0x70,0x88,0x61,0x2c,0x9f,0x0d,0x2b,0x87,0x50,0x82,0x54,0x64,0x26,0x7d,0x03,0x40, 00035 0x34,0x4b,0x1c,0x73,0xd1,0xc4,0xfd,0x3b,0xcc,0xfb,0x7f,0xab,0xe6,0x3e,0x5b,0xa5, 00036 0xad,0x04,0x23,0x9c,0x14,0x51,0x22,0xf0,0x29,0x79,0x71,0x7e,0xff,0x8c,0x0e,0xe2, 00037 0x0c,0xef,0xbc,0x72,0x75,0x6f,0x37,0xa1,0xec,0xd3,0x8e,0x62,0x8b,0x86,0x10,0xe8, 00038 0x08,0x77,0x11,0xbe,0x92,0x4f,0x24,0xc5,0x32,0x36,0x9d,0xcf,0xf3,0xa6,0xbb,0xac, 00039 0x5e,0x6c,0xa9,0x13,0x57,0x25,0xb5,0xe3,0xbd,0xa8,0x3a,0x01,0x05,0x59,0x2a,0x46 00040 }; 00041 00042 /** 00043 * The key-dependent permutation G on V^16 is a four-round Feistel network. 00044 * The round function is a fixed byte-substitution table (permutation on V^8), 00045 * the F-table. Each round of G incorporates a single byte from the key. 00046 */ 00047 #define g(tab, w, i, j, k, l) \ 00048 { \ 00049 w ^= (word)tab[i][w & 0xff] << 8; \ 00050 w ^= (word)tab[j][w >> 8]; \ 00051 w ^= (word)tab[k][w & 0xff] << 8; \ 00052 w ^= (word)tab[l][w >> 8]; \ 00053 } 00054 00055 #define g0(tab, w) g(tab, w, 0, 1, 2, 3) 00056 #define g1(tab, w) g(tab, w, 4, 5, 6, 7) 00057 #define g2(tab, w) g(tab, w, 8, 9, 0, 1) 00058 #define g3(tab, w) g(tab, w, 2, 3, 4, 5) 00059 #define g4(tab, w) g(tab, w, 6, 7, 8, 9) 00060 00061 /** 00062 * The inverse of the G permutation. 00063 */ 00064 #define h(tab, w, i, j, k, l) \ 00065 { \ 00066 w ^= (word)tab[l][w >> 8]; \ 00067 w ^= (word)tab[k][w & 0xff] << 8; \ 00068 w ^= (word)tab[j][w >> 8]; \ 00069 w ^= (word)tab[i][w & 0xff] << 8; \ 00070 } 00071 00072 #define h0(tab, w) h(tab, w, 0, 1, 2, 3) 00073 #define h1(tab, w) h(tab, w, 4, 5, 6, 7) 00074 #define h2(tab, w) h(tab, w, 8, 9, 0, 1) 00075 #define h3(tab, w) h(tab, w, 2, 3, 4, 5) 00076 #define h4(tab, w) h(tab, w, 6, 7, 8, 9) 00077 00078 /** 00079 * Preprocess a user key into a table to save an XOR at each F-table access. 00080 */ 00081 void SKIPJACK::Base::UncheckedSetKey(CipherDir dir, const byte *key, unsigned int length) 00082 { 00083 AssertValidKeyLength(length); 00084 00085 /* tab[i][c] = fTable[c ^ key[i]] */ 00086 int i; 00087 for (i = 0; i < 10; i++) { 00088 byte *t = tab[i], k = key[9-i]; 00089 int c; 00090 for (c = 0; c < 256; c++) { 00091 t[c] = fTable[c ^ k]; 00092 } 00093 } 00094 } 00095 00096 typedef BlockGetAndPut<word16, LittleEndian> Block; 00097 00098 /** 00099 * Encrypt a single block of data. 00100 */ 00101 void SKIPJACK::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const 00102 { 00103 word w1, w2, w3, w4; 00104 Block::Get(inBlock)(w4)(w3)(w2)(w1); 00105 00106 /* stepping rule A: */ 00107 g0(tab, w1); w4 ^= w1 ^ 1; 00108 g1(tab, w4); w3 ^= w4 ^ 2; 00109 g2(tab, w3); w2 ^= w3 ^ 3; 00110 g3(tab, w2); w1 ^= w2 ^ 4; 00111 g4(tab, w1); w4 ^= w1 ^ 5; 00112 g0(tab, w4); w3 ^= w4 ^ 6; 00113 g1(tab, w3); w2 ^= w3 ^ 7; 00114 g2(tab, w2); w1 ^= w2 ^ 8; 00115 00116 /* stepping rule B: */ 00117 w2 ^= w1 ^ 9; g3(tab, w1); 00118 w1 ^= w4 ^ 10; g4(tab, w4); 00119 w4 ^= w3 ^ 11; g0(tab, w3); 00120 w3 ^= w2 ^ 12; g1(tab, w2); 00121 w2 ^= w1 ^ 13; g2(tab, w1); 00122 w1 ^= w4 ^ 14; g3(tab, w4); 00123 w4 ^= w3 ^ 15; g4(tab, w3); 00124 w3 ^= w2 ^ 16; g0(tab, w2); 00125 00126 /* stepping rule A: */ 00127 g1(tab, w1); w4 ^= w1 ^ 17; 00128 g2(tab, w4); w3 ^= w4 ^ 18; 00129 g3(tab, w3); w2 ^= w3 ^ 19; 00130 g4(tab, w2); w1 ^= w2 ^ 20; 00131 g0(tab, w1); w4 ^= w1 ^ 21; 00132 g1(tab, w4); w3 ^= w4 ^ 22; 00133 g2(tab, w3); w2 ^= w3 ^ 23; 00134 g3(tab, w2); w1 ^= w2 ^ 24; 00135 00136 /* stepping rule B: */ 00137 w2 ^= w1 ^ 25; g4(tab, w1); 00138 w1 ^= w4 ^ 26; g0(tab, w4); 00139 w4 ^= w3 ^ 27; g1(tab, w3); 00140 w3 ^= w2 ^ 28; g2(tab, w2); 00141 w2 ^= w1 ^ 29; g3(tab, w1); 00142 w1 ^= w4 ^ 30; g4(tab, w4); 00143 w4 ^= w3 ^ 31; g0(tab, w3); 00144 w3 ^= w2 ^ 32; g1(tab, w2); 00145 00146 Block::Put(xorBlock, outBlock)(w4)(w3)(w2)(w1); 00147 } 00148 00149 /** 00150 * Decrypt a single block of data. 00151 */ 00152 void SKIPJACK::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const 00153 { 00154 word w1, w2, w3, w4; 00155 Block::Get(inBlock)(w4)(w3)(w2)(w1); 00156 00157 /* stepping rule A: */ 00158 h1(tab, w2); w3 ^= w2 ^ 32; 00159 h0(tab, w3); w4 ^= w3 ^ 31; 00160 h4(tab, w4); w1 ^= w4 ^ 30; 00161 h3(tab, w1); w2 ^= w1 ^ 29; 00162 h2(tab, w2); w3 ^= w2 ^ 28; 00163 h1(tab, w3); w4 ^= w3 ^ 27; 00164 h0(tab, w4); w1 ^= w4 ^ 26; 00165 h4(tab, w1); w2 ^= w1 ^ 25; 00166 00167 /* stepping rule B: */ 00168 w1 ^= w2 ^ 24; h3(tab, w2); 00169 w2 ^= w3 ^ 23; h2(tab, w3); 00170 w3 ^= w4 ^ 22; h1(tab, w4); 00171 w4 ^= w1 ^ 21; h0(tab, w1); 00172 w1 ^= w2 ^ 20; h4(tab, w2); 00173 w2 ^= w3 ^ 19; h3(tab, w3); 00174 w3 ^= w4 ^ 18; h2(tab, w4); 00175 w4 ^= w1 ^ 17; h1(tab, w1); 00176 00177 /* stepping rule A: */ 00178 h0(tab, w2); w3 ^= w2 ^ 16; 00179 h4(tab, w3); w4 ^= w3 ^ 15; 00180 h3(tab, w4); w1 ^= w4 ^ 14; 00181 h2(tab, w1); w2 ^= w1 ^ 13; 00182 h1(tab, w2); w3 ^= w2 ^ 12; 00183 h0(tab, w3); w4 ^= w3 ^ 11; 00184 h4(tab, w4); w1 ^= w4 ^ 10; 00185 h3(tab, w1); w2 ^= w1 ^ 9; 00186 00187 /* stepping rule B: */ 00188 w1 ^= w2 ^ 8; h2(tab, w2); 00189 w2 ^= w3 ^ 7; h1(tab, w3); 00190 w3 ^= w4 ^ 6; h0(tab, w4); 00191 w4 ^= w1 ^ 5; h4(tab, w1); 00192 w1 ^= w2 ^ 4; h3(tab, w2); 00193 w2 ^= w3 ^ 3; h2(tab, w3); 00194 w3 ^= w4 ^ 2; h1(tab, w4); 00195 w4 ^= w1 ^ 1; h0(tab, w1); 00196 00197 Block::Put(xorBlock, outBlock)(w4)(w3)(w2)(w1); 00198 } 00199 00200 NAMESPACE_END 00201 00202 #endif

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