Initial revision

1 files changed, 123 insertions, 0 deletions

diff --git a/gost.cpp b/gost.cpp
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+++ b/gost.cpp
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+#include "pch.h"
+#include "gost.h"
+#include "misc.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+// these are the S-boxes given in Applied Cryptography 2nd Ed., p. 333
+const byte GOST::Base::sBox[8][16]={
+	{4, 10, 9, 2, 13, 8, 0, 14, 6, 11, 1, 12, 7, 15, 5, 3},
+	{14, 11, 4, 12, 6, 13, 15, 10, 2, 3, 8, 1, 0, 7, 5, 9},
+	{5, 8, 1, 13, 10, 3, 4, 2, 14, 15, 12, 7, 6, 0, 9, 11},
+	{7, 13, 10, 1, 0, 8, 9, 15, 14, 4, 6, 12, 11, 2, 5, 3},
+	{6, 12, 7, 1, 5, 15, 13, 8, 4, 10, 9, 14, 0, 3, 11, 2},
+	{4, 11, 10, 0, 7, 2, 1, 13, 3, 6, 8, 5, 9, 12, 15, 14},
+	{13, 11, 4, 1, 3, 15, 5, 9, 0, 10, 14, 7, 6, 8, 2, 12},
+	{1, 15, 13, 0, 5, 7, 10, 4, 9, 2, 3, 14, 6, 11, 8, 12}};
+
+/*	// these are the S-boxes given in the GOST source code listing in Applied
+	// Cryptography 2nd Ed., p. 644.  they appear to be from the DES S-boxes
+	{13,  2,  8,  4,  6, 15, 11,  1, 10,  9,  3, 14,  5,  0, 12,  7 },
+	{ 4, 11,  2, 14, 15,  0,  8, 13,  3, 12,  9,  7,  5, 10,  6,  1 },
+	{12,  1, 10, 15,  9,  2,  6,  8,  0, 13,  3,  4, 14,  7,  5, 11 },
+	{ 2, 12,  4,  1,  7, 10, 11,  6,  8,  5,  3, 15, 13,  0, 14,  9 },
+	{ 7, 13, 14,  3,  0,  6,  9, 10,  1,  2,  8,  5, 11, 12,  4, 15 },
+	{10,  0,  9, 14,  6,  3, 15,  5,  1, 13, 12,  7, 11,  4,  2,  8 },
+	{15,  1,  8, 14,  6, 11,  3,  4,  9,  7,  2, 13, 12,  0,  5, 10 },
+	{14,  4, 13,  1,  2, 15, 11,  8,  3, 10,  6, 12,  5,  9,  0,  7 }}; 
+*/
+
+bool GOST::Base::sTableCalculated = false;
+word32 GOST::Base::sTable[4][256];
+
+void GOST::Base::UncheckedSetKey(CipherDir direction, const byte *userKey, unsigned int length)
+{
+	AssertValidKeyLength(length);
+
+	PrecalculateSTable();
+
+	GetUserKey(LITTLE_ENDIAN_ORDER, key.begin(), 8, userKey, KEYLENGTH);
+}
+
+void GOST::Base::PrecalculateSTable()
+{
+	if (!sTableCalculated)
+	{
+		for (unsigned i = 0; i < 4; i++)
+			for (unsigned j = 0; j < 256; j++) 
+			{
+				word32 temp = sBox[2*i][j%16] | (sBox[2*i+1][j/16] << 4);
+				sTable[i][j] = rotlMod(temp, 11+8*i);
+			}
+
+		sTableCalculated=true;
+	}
+}
+
+#define f(x)  ( t=x,												\
+				sTable[3][GETBYTE(t, 3)] ^ sTable[2][GETBYTE(t, 2)]	\
+			  ^ sTable[1][GETBYTE(t, 1)] ^ sTable[0][GETBYTE(t, 0)]	)
+
+typedef BlockGetAndPut<word32, LittleEndian> Block;
+
+void GOST::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
+{
+	word32 n1, n2, t;
+
+	Block::Get(inBlock)(n1)(n2);
+
+	for (unsigned int i=0; i<3; i++)
+	{
+		n2 ^= f(n1+key[0]);
+		n1 ^= f(n2+key[1]);
+		n2 ^= f(n1+key[2]);
+		n1 ^= f(n2+key[3]);
+		n2 ^= f(n1+key[4]);
+		n1 ^= f(n2+key[5]);
+		n2 ^= f(n1+key[6]);
+		n1 ^= f(n2+key[7]);
+	}
+
+	n2 ^= f(n1+key[7]);
+	n1 ^= f(n2+key[6]);
+	n2 ^= f(n1+key[5]);
+	n1 ^= f(n2+key[4]);
+	n2 ^= f(n1+key[3]);
+	n1 ^= f(n2+key[2]);
+	n2 ^= f(n1+key[1]);
+	n1 ^= f(n2+key[0]);
+
+	Block::Put(xorBlock, outBlock)(n2)(n1);
+}
+
+void GOST::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
+{
+	word32 n1, n2, t;
+
+	Block::Get(inBlock)(n1)(n2);
+
+	n2 ^= f(n1+key[0]);
+	n1 ^= f(n2+key[1]);
+	n2 ^= f(n1+key[2]);
+	n1 ^= f(n2+key[3]);
+	n2 ^= f(n1+key[4]);
+	n1 ^= f(n2+key[5]);
+	n2 ^= f(n1+key[6]);
+	n1 ^= f(n2+key[7]);
+
+	for (unsigned int i=0; i<3; i++)
+	{
+		n2 ^= f(n1+key[7]);
+		n1 ^= f(n2+key[6]);
+		n2 ^= f(n1+key[5]);
+		n1 ^= f(n2+key[4]);
+		n2 ^= f(n1+key[3]);
+		n1 ^= f(n2+key[2]);
+		n2 ^= f(n1+key[1]);
+		n1 ^= f(n2+key[0]);
+	}
+
+	Block::Put(xorBlock, outBlock)(n2)(n1);
+}
+
+NAMESPACE_END