178 lines
5.1 KiB
C++
178 lines
5.1 KiB
C++
// square.cpp - written and placed in the public domain by Wei Dai
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// Based on Paulo S.L.M. Barreto's public domain implementation
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#include "pch.h"
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#include "square.h"
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#include "misc.h"
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#include "gf256.h"
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NAMESPACE_BEGIN(CryptoPP)
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// apply theta to a roundkey
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static void SquareTransform (word32 in[4], word32 out[4])
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{
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static const byte G[4][4] =
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{
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0x02U, 0x01U, 0x01U, 0x03U,
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0x03U, 0x02U, 0x01U, 0x01U,
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0x01U, 0x03U, 0x02U, 0x01U,
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0x01U, 0x01U, 0x03U, 0x02U
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};
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GF256 gf256(0xf5);
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for (int i = 0; i < 4; i++)
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{
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word32 temp = 0;
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for (int j = 0; j < 4; j++)
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for (int k = 0; k < 4; k++)
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temp ^= (word32)gf256.Multiply(GETBYTE(in[i], 3-k), G[k][j]) << ((3-j)*8);
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out[i] = temp;
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}
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}
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#define roundkeys(i, j) m_roundkeys[(i)*4+(j)]
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#define roundkeys4(i) (m_roundkeys+(i)*4)
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void Square::Base::UncheckedSetKey(const byte *userKey, unsigned int length, const NameValuePairs &)
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{
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AssertValidKeyLength(length);
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static const word32 offset[ROUNDS] = {
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0x01000000UL, 0x02000000UL, 0x04000000UL, 0x08000000UL,
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0x10000000UL, 0x20000000UL, 0x40000000UL, 0x80000000UL,
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};
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GetUserKey(BIG_ENDIAN_ORDER, m_roundkeys.data(), KEYLENGTH/4, userKey, KEYLENGTH);
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/* apply the key evolution function */
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for (int i = 1; i < ROUNDS+1; i++)
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{
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roundkeys(i, 0) = roundkeys(i-1, 0) ^ rotlFixed(roundkeys(i-1, 3), 8U) ^ offset[i-1];
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roundkeys(i, 1) = roundkeys(i-1, 1) ^ roundkeys(i, 0);
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roundkeys(i, 2) = roundkeys(i-1, 2) ^ roundkeys(i, 1);
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roundkeys(i, 3) = roundkeys(i-1, 3) ^ roundkeys(i, 2);
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}
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/* produce the round keys */
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if (IsForwardTransformation())
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{
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for (int i = 0; i < ROUNDS; i++)
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SquareTransform (roundkeys4(i), roundkeys4(i));
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}
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else
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{
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for (int i = 0; i < ROUNDS/2; i++)
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for (int j = 0; j < 4; j++)
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std::swap(roundkeys(i, j), roundkeys(ROUNDS-i, j));
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SquareTransform (roundkeys4(ROUNDS), roundkeys4(ROUNDS));
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}
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}
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#define MSB(x) (((x) >> 24) & 0xffU) /* most significant byte */
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#define SSB(x) (((x) >> 16) & 0xffU) /* second in significance */
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#define TSB(x) (((x) >> 8) & 0xffU) /* third in significance */
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#define LSB(x) (((x) ) & 0xffU) /* least significant byte */
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#define squareRound(text, temp, T0, T1, T2, T3, roundkey) \
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{ \
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temp[0] = T0[MSB (text[0])] \
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^ T1[MSB (text[1])] \
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^ T2[MSB (text[2])] \
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^ T3[MSB (text[3])] \
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^ roundkey[0]; \
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temp[1] = T0[SSB (text[0])] \
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^ T1[SSB (text[1])] \
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^ T2[SSB (text[2])] \
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^ T3[SSB (text[3])] \
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^ roundkey[1]; \
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temp[2] = T0[TSB (text[0])] \
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^ T1[TSB (text[1])] \
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^ T2[TSB (text[2])] \
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^ T3[TSB (text[3])] \
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^ roundkey[2]; \
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temp[3] = T0[LSB (text[0])] \
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^ T1[LSB (text[1])] \
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^ T2[LSB (text[2])] \
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^ T3[LSB (text[3])] \
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^ roundkey[3]; \
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} /* squareRound */
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#define squareFinal(text, temp, S, roundkey) \
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{ \
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text[0] = ((word32) (S[MSB (temp[0])]) << 24) \
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^ ((word32) (S[MSB (temp[1])]) << 16) \
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^ ((word32) (S[MSB (temp[2])]) << 8) \
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^ (word32) (S[MSB (temp[3])]) \
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^ roundkey[0]; \
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text[1] = ((word32) (S[SSB (temp[0])]) << 24) \
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^ ((word32) (S[SSB (temp[1])]) << 16) \
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^ ((word32) (S[SSB (temp[2])]) << 8) \
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^ (word32) (S[SSB (temp[3])]) \
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^ roundkey[1]; \
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text[2] = ((word32) (S[TSB (temp[0])]) << 24) \
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^ ((word32) (S[TSB (temp[1])]) << 16) \
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^ ((word32) (S[TSB (temp[2])]) << 8) \
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^ (word32) (S[TSB (temp[3])]) \
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^ roundkey[2]; \
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text[3] = ((word32) (S[LSB (temp[0])]) << 24) \
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^ ((word32) (S[LSB (temp[1])]) << 16) \
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^ ((word32) (S[LSB (temp[2])]) << 8) \
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^ (word32) (S[LSB (temp[3])]) \
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^ roundkey[3]; \
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} /* squareFinal */
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typedef BlockGetAndPut<word32, BigEndian> Block;
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void Square::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
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{
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word32 text[4], temp[4];
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Block::Get(inBlock)(text[0])(text[1])(text[2])(text[3]);
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/* initial key addition */
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text[0] ^= roundkeys(0, 0);
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text[1] ^= roundkeys(0, 1);
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text[2] ^= roundkeys(0, 2);
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text[3] ^= roundkeys(0, 3);
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/* ROUNDS - 1 full rounds */
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for (int i=1; i+1<ROUNDS; i+=2)
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{
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squareRound (text, temp, Te[0], Te[1], Te[2], Te[3], roundkeys4(i));
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squareRound (temp, text, Te[0], Te[1], Te[2], Te[3], roundkeys4(i+1));
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}
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squareRound (text, temp, Te[0], Te[1], Te[2], Te[3], roundkeys4(ROUNDS-1));
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/* last round (diffusion becomes only transposition) */
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squareFinal (text, temp, Se, roundkeys4(ROUNDS));
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Block::Put(xorBlock, outBlock)(text[0])(text[1])(text[2])(text[3]);
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}
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void Square::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
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{
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word32 text[4], temp[4];
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Block::Get(inBlock)(text[0])(text[1])(text[2])(text[3]);
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/* initial key addition */
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text[0] ^= roundkeys(0, 0);
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text[1] ^= roundkeys(0, 1);
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text[2] ^= roundkeys(0, 2);
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text[3] ^= roundkeys(0, 3);
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/* ROUNDS - 1 full rounds */
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for (int i=1; i+1<ROUNDS; i+=2)
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{
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squareRound (text, temp, Td[0], Td[1], Td[2], Td[3], roundkeys4(i));
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squareRound (temp, text, Td[0], Td[1], Td[2], Td[3], roundkeys4(i+1));
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}
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squareRound (text, temp, Td[0], Td[1], Td[2], Td[3], roundkeys4(ROUNDS-1));
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/* last round (diffusion becomes only transposition) */
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squareFinal (text, temp, Sd, roundkeys4(ROUNDS));
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Block::Put(xorBlock, outBlock)(text[0])(text[1])(text[2])(text[3]);
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}
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NAMESPACE_END
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