Updated MersenneTwister tests

The tests now include the first 10 elements of the sequence to ensure a properly implemented algorithm and endianess correctness.

1 files changed, 37 insertions, 21 deletions

diff --git a/mersenne.h b/mersenne.h
index 4937d9d0..d5bd039b 100644
--- a/mersenne.h
+++ b/mersenne.h
@@ -26,7 +26,7 @@ NAMESPACE_BEGIN(CryptoPP)
 //!   required quickly. It should not be used for cryptographic purposes.

 //! \sa MT19937, MT19937ar

 //! \since Crypto++ 5.6.3

-template <unsigned int K, unsigned int M, unsigned int N, unsigned int F, unsigned long S>

+template <unsigned int K, unsigned int M, unsigned int N, unsigned int F, word32 S>

 class MersenneTwister : public RandomNumberGenerator

 {

 public:

@@ -38,11 +38,26 @@ public:
 	//! \param seed 32-bit seed

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

 	//!   parameters over time

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

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

 	{

-		m_state[0] = seed;

-		for (unsigned int i = 1; i < N+1; i++)

-			m_state[i] = word32(F * (m_state[i-1] ^ (m_state[i-1] >> 30)) + i);

+		Reset(seed);

+	}

+

+	bool CanIncorporateEntropy() const {return true;}

+

+	//! \brief Update RNG state with additional unpredictable values

+	//! \param input the entropy to add to the generator

+	//! \param length the size of the input buffer

+	//! \details MersenneTwister uses the first 32-bits of <tt>input</tt> to reseed the

+    //!   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);

+

+		// Wipe temp

+		SecureWipeArray(&temp, 1);

 	}

 

 	//! \brief Generate random array of bytes

@@ -58,24 +73,15 @@ public:
 		word32 temp;

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

 		{

-#if defined(CRYPTOPP_ALLOW_UNALIGNED_DATA_ACCESS) && defined(IS_LITTLE_ENDIAN)

-			*((word32*)output) = ByteReverse(NextMersenneWord());

-#elif defined(CRYPTOPP_ALLOW_UNALIGNED_DATA_ACCESS)

-			*((word32*)output) = NextMersenneWord();

-#else

 			temp = NextMersenneWord();

-			output[3] = CRYPTOPP_GET_BYTE_AS_BYTE(temp, 0);

-			output[2] = CRYPTOPP_GET_BYTE_AS_BYTE(temp, 1);

-			output[1] = CRYPTOPP_GET_BYTE_AS_BYTE(temp, 2);

-			output[0] = CRYPTOPP_GET_BYTE_AS_BYTE(temp, 3);

-#endif

+			PutWord<word32>(false, LITTLE_ENDIAN_ORDER, output, temp);

 		}

 

 		// No tail bytes

 		if (size%4 == 0)

 		{

 			// Wipe temp

-			*((volatile word32*)&temp) = 0;

+			SecureWipeArray(&temp, 1);

 			return;

 		}

 

@@ -91,7 +97,7 @@ public:
 		}

 

 		// Wipe temp

-		*((volatile word32*)&temp) = 0;

+		SecureWipeArray(&temp, 1);

 	}

 

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

@@ -128,6 +134,16 @@ public:
 

 protected:

 

+	void Reset(word32 seed)

+	{

+		m_seed = seed;

+		m_idx = N;

+

+		m_state[0] = seed;

+		for (unsigned int i = 1; i < N+1; i++)

+			m_state[i] = word32(F * (m_state[i-1] ^ (m_state[i-1] >> 30)) + i);

+	}

+

 	//! \brief Returns the next 32-bit word from the state array

 	//! \returns the next 32-bit word from the state array

 	//! \details fetches the next word frm the state array, performs bit operations on

@@ -148,7 +164,7 @@ protected:
 	//! \brief Performs the twist operaton on the state array

 	void Twist()

 	{

-		static const unsigned long magic[2]={0x0UL, K};

+		static const word32 magic[2]={0x0UL, K};

 		word32 kk, temp;

 

 		CRYPTOPP_ASSERT(N >= M);

@@ -171,7 +187,7 @@ protected:
 		m_idx = 0;

 

 		// Wipe temp

-		*((volatile word32*)&temp) = 0;

+		SecureWipeArray(&temp, 1);

 	}

 

 private:

@@ -179,9 +195,9 @@ private:
 	//! \brief 32-bit word state array of size N

 	FixedSizeSecBlock<word32, N+1> m_state;

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

-	unsigned int m_seed;

+	word32 m_seed;

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

-	unsigned int m_idx;

+	word32 m_idx;

 };

 

 //! \class MT19937