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square.cpp

00001 // square.cpp - written and placed in the public domain by Wei Dai 00002 // Based on Paulo S.L.M. Barreto's public domain implementation 00003 00004 #include "pch.h" 00005 #include "square.h" 00006 #include "misc.h" 00007 #include "gf256.h" 00008 00009 NAMESPACE_BEGIN(CryptoPP) 00010 00011 // apply theta to a roundkey 00012 static void SquareTransform (word32 in[4], word32 out[4]) 00013 { 00014 static const byte G[4][4] = 00015 { 00016 0x02U, 0x01U, 0x01U, 0x03U, 00017 0x03U, 0x02U, 0x01U, 0x01U, 00018 0x01U, 0x03U, 0x02U, 0x01U, 00019 0x01U, 0x01U, 0x03U, 0x02U 00020 }; 00021 00022 GF256 gf256(0xf5); 00023 00024 for (int i = 0; i < 4; i++) 00025 { 00026 word32 temp = 0; 00027 for (int j = 0; j < 4; j++) 00028 for (int k = 0; k < 4; k++) 00029 temp ^= (word32)gf256.Multiply(GETBYTE(in[i], 3-k), G[k][j]) << ((3-j)*8); 00030 out[i] = temp; 00031 } 00032 } 00033 00034 void Square::Base::UncheckedSetKey(CipherDir dir, const byte *userKey, unsigned int length) 00035 { 00036 AssertValidKeyLength(length); 00037 00038 static const word32 offset[ROUNDS] = { 00039 0x01000000UL, 0x02000000UL, 0x04000000UL, 0x08000000UL, 00040 0x10000000UL, 0x20000000UL, 0x40000000UL, 0x80000000UL, 00041 }; 00042 00043 GetUserKey(BIG_ENDIAN_ORDER, roundkeys[0], KEYLENGTH/4, userKey, KEYLENGTH); 00044 00045 /* apply the key evolution function */ 00046 for (int i = 1; i < ROUNDS+1; i++) 00047 { 00048 roundkeys[i][0] = roundkeys[i-1][0] ^ rotlFixed(roundkeys[i-1][3], 8U) ^ offset[i-1]; 00049 roundkeys[i][1] = roundkeys[i-1][1] ^ roundkeys[i][0]; 00050 roundkeys[i][2] = roundkeys[i-1][2] ^ roundkeys[i][1]; 00051 roundkeys[i][3] = roundkeys[i-1][3] ^ roundkeys[i][2]; 00052 } 00053 00054 /* produce the round keys */ 00055 if (dir == ENCRYPTION) 00056 { 00057 for (int i = 0; i < ROUNDS; i++) 00058 SquareTransform (roundkeys[i], roundkeys[i]); 00059 } 00060 else 00061 { 00062 for (int i = 0; i < ROUNDS/2; i++) 00063 for (int j = 0; j < 4; j++) 00064 std::swap(roundkeys[i][j], roundkeys[ROUNDS-i][j]); 00065 SquareTransform (roundkeys[ROUNDS], roundkeys[ROUNDS]); 00066 } 00067 } 00068 00069 #define MSB(x) (((x) >> 24) & 0xffU) /* most significant byte */ 00070 #define SSB(x) (((x) >> 16) & 0xffU) /* second in significance */ 00071 #define TSB(x) (((x) >> 8) & 0xffU) /* third in significance */ 00072 #define LSB(x) (((x) ) & 0xffU) /* least significant byte */ 00073 00074 #define squareRound(text, temp, T0, T1, T2, T3, roundkey) \ 00075 { \ 00076 temp[0] = T0[MSB (text[0])] \ 00077 ^ T1[MSB (text[1])] \ 00078 ^ T2[MSB (text[2])] \ 00079 ^ T3[MSB (text[3])] \ 00080 ^ roundkey[0]; \ 00081 temp[1] = T0[SSB (text[0])] \ 00082 ^ T1[SSB (text[1])] \ 00083 ^ T2[SSB (text[2])] \ 00084 ^ T3[SSB (text[3])] \ 00085 ^ roundkey[1]; \ 00086 temp[2] = T0[TSB (text[0])] \ 00087 ^ T1[TSB (text[1])] \ 00088 ^ T2[TSB (text[2])] \ 00089 ^ T3[TSB (text[3])] \ 00090 ^ roundkey[2]; \ 00091 temp[3] = T0[LSB (text[0])] \ 00092 ^ T1[LSB (text[1])] \ 00093 ^ T2[LSB (text[2])] \ 00094 ^ T3[LSB (text[3])] \ 00095 ^ roundkey[3]; \ 00096 } /* squareRound */ 00097 00098 #define squareFinal(text, temp, S, roundkey) \ 00099 { \ 00100 text[0] = ((word32) (S[MSB (temp[0])]) << 24) \ 00101 ^ ((word32) (S[MSB (temp[1])]) << 16) \ 00102 ^ ((word32) (S[MSB (temp[2])]) << 8) \ 00103 ^ (word32) (S[MSB (temp[3])]) \ 00104 ^ roundkey[0]; \ 00105 text[1] = ((word32) (S[SSB (temp[0])]) << 24) \ 00106 ^ ((word32) (S[SSB (temp[1])]) << 16) \ 00107 ^ ((word32) (S[SSB (temp[2])]) << 8) \ 00108 ^ (word32) (S[SSB (temp[3])]) \ 00109 ^ roundkey[1]; \ 00110 text[2] = ((word32) (S[TSB (temp[0])]) << 24) \ 00111 ^ ((word32) (S[TSB (temp[1])]) << 16) \ 00112 ^ ((word32) (S[TSB (temp[2])]) << 8) \ 00113 ^ (word32) (S[TSB (temp[3])]) \ 00114 ^ roundkey[2]; \ 00115 text[3] = ((word32) (S[LSB (temp[0])]) << 24) \ 00116 ^ ((word32) (S[LSB (temp[1])]) << 16) \ 00117 ^ ((word32) (S[LSB (temp[2])]) << 8) \ 00118 ^ (word32) (S[LSB (temp[3])]) \ 00119 ^ roundkey[3]; \ 00120 } /* squareFinal */ 00121 00122 typedef BlockGetAndPut<word32, BigEndian> Block; 00123 00124 void Square::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const 00125 { 00126 word32 text[4], temp[4]; 00127 Block::Get(inBlock)(text[0])(text[1])(text[2])(text[3]); 00128 00129 /* initial key addition */ 00130 text[0] ^= roundkeys[0][0]; 00131 text[1] ^= roundkeys[0][1]; 00132 text[2] ^= roundkeys[0][2]; 00133 text[3] ^= roundkeys[0][3]; 00134 00135 /* ROUNDS - 1 full rounds */ 00136 for (int i=1; i+1<ROUNDS; i+=2) 00137 { 00138 squareRound (text, temp, Te[0], Te[1], Te[2], Te[3], roundkeys[i]); 00139 squareRound (temp, text, Te[0], Te[1], Te[2], Te[3], roundkeys[i+1]); 00140 } 00141 squareRound (text, temp, Te[0], Te[1], Te[2], Te[3], roundkeys[ROUNDS-1]); 00142 00143 /* last round (diffusion becomes only transposition) */ 00144 squareFinal (text, temp, Se, roundkeys[ROUNDS]); 00145 00146 Block::Put(xorBlock, outBlock)(text[0])(text[1])(text[2])(text[3]); 00147 } 00148 00149 void Square::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const 00150 { 00151 word32 text[4], temp[4]; 00152 Block::Get(inBlock)(text[0])(text[1])(text[2])(text[3]); 00153 00154 /* initial key addition */ 00155 text[0] ^= roundkeys[0][0]; 00156 text[1] ^= roundkeys[0][1]; 00157 text[2] ^= roundkeys[0][2]; 00158 text[3] ^= roundkeys[0][3]; 00159 00160 /* ROUNDS - 1 full rounds */ 00161 for (int i=1; i+1<ROUNDS; i+=2) 00162 { 00163 squareRound (text, temp, Td[0], Td[1], Td[2], Td[3], roundkeys[i]); 00164 squareRound (temp, text, Td[0], Td[1], Td[2], Td[3], roundkeys[i+1]); 00165 } 00166 squareRound (text, temp, Td[0], Td[1], Td[2], Td[3], roundkeys[ROUNDS-1]); 00167 00168 /* last round (diffusion becomes only transposition) */ 00169 squareFinal (text, temp, Sd, roundkeys[ROUNDS]); 00170 00171 Block::Put(xorBlock, outBlock)(text[0])(text[1])(text[2])(text[3]); 00172 } 00173 00174 NAMESPACE_END

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