Update MersenneTwister class

1 files changed, 22 insertions, 24 deletions

diff --git a/mersenne.h b/mersenne.h
index 96f22940..2b2af111 100644
--- a/mersenne.h
+++ b/mersenne.h
@@ -39,7 +39,7 @@ public:
 	/// \param seed 32-bit seed

 	/// \details Defaults to template parameter S due to changing algorithm

 	///  parameters over time

-	MersenneTwister(word32 seed = S) : m_seed(seed), m_idx(N)

+	MersenneTwister(word32 seed = S) : m_idx(N)

 	{

 		Reset(seed);

 	}

@@ -53,12 +53,20 @@ public:
 	///  generator. If fewer bytes are provided, then the seed is padded with 0's.

 	void IncorporateEntropy(const byte *input, size_t length)

 	{

-		word32 temp = 0;

-		::memcpy(&temp, input, STDMIN(sizeof(temp), length));

-		Reset(temp);

+		// Handle word32 size blocks

+		SecBlock<word32> temp(1);

+		temp[0] = 0;

 

-		// Wipe temp

-		SecureWipeArray(&temp, 1);

+		if (length > 4)

+			length = 4;

+

+		for (size_t i=0; i<length; ++i)

+		{

+			temp[0] <<= 8;

+			temp[0] = temp[0] | input[i];

+		}

+

+		Reset(temp[0]);

 	}

 

 	/// \brief Generate random array of bytes

@@ -71,34 +79,27 @@ public:
 	void GenerateBlock(byte *output, size_t size)

 	{

 		// Handle word32 size blocks

-		word32 temp;

+		SecBlock<word32> temp(1);

 		for (size_t i=0; i < size/4; i++, output += 4)

 		{

-			temp = NextMersenneWord();

-			memcpy(output, &temp, 4);

+			temp[0] = NextMersenneWord();

+			memcpy(output, temp+0, 4);

 		}

 

 		// No tail bytes

 		if (size%4 == 0)

-		{

-			// Wipe temp

-			SecureWipeArray(&temp, 1);

 			return;

-		}

 

 		// Handle tail bytes

-		temp = NextMersenneWord();

+		temp[0] = NextMersenneWord();

 		switch (size%4)

 		{

-			case 3: output[2] = CRYPTOPP_GET_BYTE_AS_BYTE(temp, 1); /* fall through */

-			case 2: output[1] = CRYPTOPP_GET_BYTE_AS_BYTE(temp, 2); /* fall through */

-			case 1: output[0] = CRYPTOPP_GET_BYTE_AS_BYTE(temp, 3); break;

+			case 3: output[2] = CRYPTOPP_GET_BYTE_AS_BYTE(temp[0], 1); /* fall through */

+			case 2: output[1] = CRYPTOPP_GET_BYTE_AS_BYTE(temp[0], 2); /* fall through */

+			case 1: output[0] = CRYPTOPP_GET_BYTE_AS_BYTE(temp[0], 3); break;

 

-			default: CRYPTOPP_ASSERT(0); ;

+			default: CRYPTOPP_ASSERT(0);;

 		}

-

-		// Wipe temp

-		SecureWipeArray(&temp, 1);

 	}

 

 	/// \brief Generate a random 32-bit word in the range min to max, inclusive

@@ -137,7 +138,6 @@ protected:
 

 	void Reset(word32 seed)

 	{

-		m_seed = seed;

 		m_idx = N;

 

 		m_state[0] = seed;

@@ -195,8 +195,6 @@ private:
 

 	/// \brief 32-bit word state array of size N

 	FixedSizeSecBlock<word32, N+1> m_state;

-	/// \brief the value used to seed the generator

-	word32 m_seed;

 	/// \brief the current index into the state array

 	word32 m_idx;

 };