1// skipjack.cpp - modified by Wei Dai from Paulo Barreto's skipjack32.c, 2// which is public domain according to his web site. 3 4#include "pch.h" 5 6#ifndef CRYPTOPP_IMPORTS 7 8#include "skipjack.h" 9 10/* 11 * Optimized implementation of SKIPJACK algorithm 12 * 13 * originally written by Panu Rissanen <bande@lut.fi> 1998.06.24 14 * optimized by Mark Tillotson <markt@chaos.org.uk> 1998.06.25 15 * optimized by Paulo Barreto <pbarreto@nw.com.br> 1998.06.30 16 */ 17 18NAMESPACE_BEGIN(CryptoPP) 19 20/** 21 * The F-table byte permutation (see description of the G-box permutation) 22 */ 23const byte SKIPJACK::Base::fTable[256] = { 24 0xa3,0xd7,0x09,0x83,0xf8,0x48,0xf6,0xf4,0xb3,0x21,0x15,0x78,0x99,0xb1,0xaf,0xf9, 25 0xe7,0x2d,0x4d,0x8a,0xce,0x4c,0xca,0x2e,0x52,0x95,0xd9,0x1e,0x4e,0x38,0x44,0x28, 26 0x0a,0xdf,0x02,0xa0,0x17,0xf1,0x60,0x68,0x12,0xb7,0x7a,0xc3,0xe9,0xfa,0x3d,0x53, 27 0x96,0x84,0x6b,0xba,0xf2,0x63,0x9a,0x19,0x7c,0xae,0xe5,0xf5,0xf7,0x16,0x6a,0xa2, 28 0x39,0xb6,0x7b,0x0f,0xc1,0x93,0x81,0x1b,0xee,0xb4,0x1a,0xea,0xd0,0x91,0x2f,0xb8, 29 0x55,0xb9,0xda,0x85,0x3f,0x41,0xbf,0xe0,0x5a,0x58,0x80,0x5f,0x66,0x0b,0xd8,0x90, 30 0x35,0xd5,0xc0,0xa7,0x33,0x06,0x65,0x69,0x45,0x00,0x94,0x56,0x6d,0x98,0x9b,0x76, 31 0x97,0xfc,0xb2,0xc2,0xb0,0xfe,0xdb,0x20,0xe1,0xeb,0xd6,0xe4,0xdd,0x47,0x4a,0x1d, 32 0x42,0xed,0x9e,0x6e,0x49,0x3c,0xcd,0x43,0x27,0xd2,0x07,0xd4,0xde,0xc7,0x67,0x18, 33 0x89,0xcb,0x30,0x1f,0x8d,0xc6,0x8f,0xaa,0xc8,0x74,0xdc,0xc9,0x5d,0x5c,0x31,0xa4, 34 0x70,0x88,0x61,0x2c,0x9f,0x0d,0x2b,0x87,0x50,0x82,0x54,0x64,0x26,0x7d,0x03,0x40, 35 0x34,0x4b,0x1c,0x73,0xd1,0xc4,0xfd,0x3b,0xcc,0xfb,0x7f,0xab,0xe6,0x3e,0x5b,0xa5, 36 0xad,0x04,0x23,0x9c,0x14,0x51,0x22,0xf0,0x29,0x79,0x71,0x7e,0xff,0x8c,0x0e,0xe2, 37 0x0c,0xef,0xbc,0x72,0x75,0x6f,0x37,0xa1,0xec,0xd3,0x8e,0x62,0x8b,0x86,0x10,0xe8, 38 0x08,0x77,0x11,0xbe,0x92,0x4f,0x24,0xc5,0x32,0x36,0x9d,0xcf,0xf3,0xa6,0xbb,0xac, 39 0x5e,0x6c,0xa9,0x13,0x57,0x25,0xb5,0xe3,0xbd,0xa8,0x3a,0x01,0x05,0x59,0x2a,0x46 40}; 41 42/** 43 * The key-dependent permutation G on V^16 is a four-round Feistel network. 44 * The round function is a fixed byte-substitution table (permutation on V^8), 45 * the F-table. Each round of G incorporates a single byte from the key. 46 */ 47#define g(tab, w, i, j, k, l) \ 48{ \ 49 w ^= (word)tab[i][w & 0xff] << 8; \ 50 w ^= (word)tab[j][w >> 8]; \ 51 w ^= (word)tab[k][w & 0xff] << 8; \ 52 w ^= (word)tab[l][w >> 8]; \ 53} 54 55#define g0(tab, w) g(tab, w, 0, 1, 2, 3) 56#define g1(tab, w) g(tab, w, 4, 5, 6, 7) 57#define g2(tab, w) g(tab, w, 8, 9, 0, 1) 58#define g3(tab, w) g(tab, w, 2, 3, 4, 5) 59#define g4(tab, w) g(tab, w, 6, 7, 8, 9) 60 61/** 62 * The inverse of the G permutation. 63 */ 64#define h(tab, w, i, j, k, l) \ 65{ \ 66 w ^= (word)tab[l][w >> 8]; \ 67 w ^= (word)tab[k][w & 0xff] << 8; \ 68 w ^= (word)tab[j][w >> 8]; \ 69 w ^= (word)tab[i][w & 0xff] << 8; \ 70} 71 72#define h0(tab, w) h(tab, w, 0, 1, 2, 3) 73#define h1(tab, w) h(tab, w, 4, 5, 6, 7) 74#define h2(tab, w) h(tab, w, 8, 9, 0, 1) 75#define h3(tab, w) h(tab, w, 2, 3, 4, 5) 76#define h4(tab, w) h(tab, w, 6, 7, 8, 9) 77 78/** 79 * Preprocess a user key into a table to save an XOR at each F-table access. 80 */ 81void SKIPJACK::Base::UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs &) 82{ 83 AssertValidKeyLength(length); 84 85 /* tab[i][c] = fTable[c ^ key[i]] */ 86 int i; 87 for (i = 0; i < 10; i++) { 88 byte *t = tab[i], k = key[9-i]; 89 int c; 90 for (c = 0; c < 256; c++) { 91 t[c] = fTable[c ^ k]; 92 } 93 } 94} 95 96typedef BlockGetAndPut<word16, LittleEndian> Block; 97 98/** 99 * Encrypt a single block of data. 100 */ 101void SKIPJACK::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const 102{ 103 word16 w1, w2, w3, w4; 104 Block::Get(inBlock)(w4)(w3)(w2)(w1); 105 106 /* stepping rule A: */ 107 g0(tab, w1); w4 ^= w1 ^ 1; 108 g1(tab, w4); w3 ^= w4 ^ 2; 109 g2(tab, w3); w2 ^= w3 ^ 3; 110 g3(tab, w2); w1 ^= w2 ^ 4; 111 g4(tab, w1); w4 ^= w1 ^ 5; 112 g0(tab, w4); w3 ^= w4 ^ 6; 113 g1(tab, w3); w2 ^= w3 ^ 7; 114 g2(tab, w2); w1 ^= w2 ^ 8; 115 116 /* stepping rule B: */ 117 w2 ^= w1 ^ 9; g3(tab, w1); 118 w1 ^= w4 ^ 10; g4(tab, w4); 119 w4 ^= w3 ^ 11; g0(tab, w3); 120 w3 ^= w2 ^ 12; g1(tab, w2); 121 w2 ^= w1 ^ 13; g2(tab, w1); 122 w1 ^= w4 ^ 14; g3(tab, w4); 123 w4 ^= w3 ^ 15; g4(tab, w3); 124 w3 ^= w2 ^ 16; g0(tab, w2); 125 126 /* stepping rule A: */ 127 g1(tab, w1); w4 ^= w1 ^ 17; 128 g2(tab, w4); w3 ^= w4 ^ 18; 129 g3(tab, w3); w2 ^= w3 ^ 19; 130 g4(tab, w2); w1 ^= w2 ^ 20; 131 g0(tab, w1); w4 ^= w1 ^ 21; 132 g1(tab, w4); w3 ^= w4 ^ 22; 133 g2(tab, w3); w2 ^= w3 ^ 23; 134 g3(tab, w2); w1 ^= w2 ^ 24; 135 136 /* stepping rule B: */ 137 w2 ^= w1 ^ 25; g4(tab, w1); 138 w1 ^= w4 ^ 26; g0(tab, w4); 139 w4 ^= w3 ^ 27; g1(tab, w3); 140 w3 ^= w2 ^ 28; g2(tab, w2); 141 w2 ^= w1 ^ 29; g3(tab, w1); 142 w1 ^= w4 ^ 30; g4(tab, w4); 143 w4 ^= w3 ^ 31; g0(tab, w3); 144 w3 ^= w2 ^ 32; g1(tab, w2); 145 146 Block::Put(xorBlock, outBlock)(w4)(w3)(w2)(w1); 147} 148 149/** 150 * Decrypt a single block of data. 151 */ 152void SKIPJACK::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const 153{ 154 word16 w1, w2, w3, w4; 155 Block::Get(inBlock)(w4)(w3)(w2)(w1); 156 157 /* stepping rule A: */ 158 h1(tab, w2); w3 ^= w2 ^ 32; 159 h0(tab, w3); w4 ^= w3 ^ 31; 160 h4(tab, w4); w1 ^= w4 ^ 30; 161 h3(tab, w1); w2 ^= w1 ^ 29; 162 h2(tab, w2); w3 ^= w2 ^ 28; 163 h1(tab, w3); w4 ^= w3 ^ 27; 164 h0(tab, w4); w1 ^= w4 ^ 26; 165 h4(tab, w1); w2 ^= w1 ^ 25; 166 167 /* stepping rule B: */ 168 w1 ^= w2 ^ 24; h3(tab, w2); 169 w2 ^= w3 ^ 23; h2(tab, w3); 170 w3 ^= w4 ^ 22; h1(tab, w4); 171 w4 ^= w1 ^ 21; h0(tab, w1); 172 w1 ^= w2 ^ 20; h4(tab, w2); 173 w2 ^= w3 ^ 19; h3(tab, w3); 174 w3 ^= w4 ^ 18; h2(tab, w4); 175 w4 ^= w1 ^ 17; h1(tab, w1); 176 177 /* stepping rule A: */ 178 h0(tab, w2); w3 ^= w2 ^ 16; 179 h4(tab, w3); w4 ^= w3 ^ 15; 180 h3(tab, w4); w1 ^= w4 ^ 14; 181 h2(tab, w1); w2 ^= w1 ^ 13; 182 h1(tab, w2); w3 ^= w2 ^ 12; 183 h0(tab, w3); w4 ^= w3 ^ 11; 184 h4(tab, w4); w1 ^= w4 ^ 10; 185 h3(tab, w1); w2 ^= w1 ^ 9; 186 187 /* stepping rule B: */ 188 w1 ^= w2 ^ 8; h2(tab, w2); 189 w2 ^= w3 ^ 7; h1(tab, w3); 190 w3 ^= w4 ^ 6; h0(tab, w4); 191 w4 ^= w1 ^ 5; h4(tab, w1); 192 w1 ^= w2 ^ 4; h3(tab, w2); 193 w2 ^= w3 ^ 3; h2(tab, w3); 194 w3 ^= w4 ^ 2; h1(tab, w4); 195 w4 ^= w1 ^ 1; h0(tab, w1); 196 197 Block::Put(xorBlock, outBlock)(w4)(w3)(w2)(w1); 198} 199 200NAMESPACE_END 201 202#endif 203