merge S,P,L for GOST R 34.11-2012

Gost.cpp

@@ -185,20 +185,7 @@ namespace crypto
 		0x492c024284fbaec0, 0xaa16012142f35760, 0x550b8e9e21f7a530, 0xa48b474f9ef5dc18,
 		0x70a6a56e2440598e, 0x3853dc371220a247, 0x1ca76e95091051ad, 0x0edd37c48a08a6d8,
 		0x07e095624504536c, 0x8d70c431ac02a736, 0xc83862965601dd1b, 0x641c314b2b8ee083
-	}; // in Little Endian
-
-	static const uint8_t T_[64]=
-	{
-		 0,  8, 16, 24, 32, 40, 48, 56, 
-		 1,  9, 17, 25, 33, 41, 49, 57,
-		 2, 10, 18, 26, 34, 42, 50, 58, 
-		 3, 11, 19, 27, 35, 43, 51, 59,
-		 4, 12, 20, 28, 36, 44, 52, 60,
-		 5, 13, 21, 29, 37, 45, 53, 61,
-		 6, 14, 22, 30, 38, 46, 54, 62,
-		 7, 15, 23, 31, 39, 47, 55, 63
-	};
-
+	}; 
 
 	static const uint8_t C_[12][64] = 
 	{
@@ -320,21 +307,17 @@ namespace crypto
 			}
 		}
 
-		void S ()
-		{
-			for (int i = 0; i < 64; i++)
-				buf[i] = sbox_[buf[i]];
-		}	
-
-		void L ()
+		void SPL ()
 		{
+			uint8_t p[64];
+			memcpy (p, buf, 64); // we need to copy it for P's transposition
 			for (int i = 0; i < 8; i++)
 			{
 				uint64_t c = 0;
 				for (int j = 0; j < 8; j++)
 				{	
 					uint8_t bit = 0x80;
-					uint8_t byte = buf[i*8+j];
+					uint8_t byte = sbox_[p[j*8+i]]; // S - sbox_, P - transpose (i,j)
 					for (int k = 0; k < 8; k++)
 					{
 						if (byte & bit) c ^= A_[j*8+k];
@@ -345,27 +328,15 @@ namespace crypto
 			}	
 		}	
 
-		void P ()
-		{
-			uint8_t t[64];
-			for (int i = 0; i < 64; i++)
-				t[i] = buf[T_[i]];
-			memcpy (buf, t, 64);			
-		}
-
 		GOST3411Block E (const GOST3411Block& m)
 		{
 			GOST3411Block k = *this;
 			GOST3411Block res = k^m;
 			for (int i = 0; i < 12; i++)
 			{
-				res.S ();
-				res.P ();
-				res.L ();
+				res.SPL ();
 				k = k^C_[i];
-				k.S ();
-				k.P ();
-				k.L ();
+				k.SPL ();
 				res = k^res;
 			}	
 			return res;
@@ -375,9 +346,7 @@ namespace crypto
 	static GOST3411Block gN (const GOST3411Block& N, const GOST3411Block& h, const GOST3411Block& m)
 	{
 		GOST3411Block res = N ^ h;
-		res.S ();
-		res.P ();
-		res.L ();
+		res.SPL ();
 		res = res.E (m);
 		res = res^h;
 		res = res^m;