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externals/cryptopp/blumshub.h

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+// blumshub.h - originally written and placed in the public domain by Wei Dai
+
+/// \file blumshub.h
+/// \brief Classes for Blum Blum Shub generator
+
+#ifndef CRYPTOPP_BLUMSHUB_H
+#define CRYPTOPP_BLUMSHUB_H
+
+#include "cryptlib.h"
+#include "modarith.h"
+#include "integer.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+/// \brief BlumBlumShub without factorization of the modulus
+/// \details You should reseed the generator after a fork() to avoid multiple generators
+///  with the same internal state.
+class PublicBlumBlumShub : public RandomNumberGenerator,
+						   public StreamTransformation
+{
+public:
+	virtual ~PublicBlumBlumShub() {}
+
+	/// \brief Construct a PublicBlumBlumShub
+	/// \param n the modulus
+	/// \param seed the seed for the generator
+	/// \details seed is the secret key and should be about as large as n.
+	PublicBlumBlumShub(const Integer &n, const Integer &seed);
+
+	unsigned int GenerateBit();
+	byte GenerateByte();
+	void GenerateBlock(byte *output, size_t size);
+	void ProcessData(byte *outString, const byte *inString, size_t length);
+
+	bool IsSelfInverting() const {return true;}
+	bool IsForwardTransformation() const {return true;}
+
+protected:
+	ModularArithmetic modn;
+	Integer current;
+	word maxBits, bitsLeft;
+};
+
+/// \brief BlumBlumShub with factorization of the modulus
+/// \details You should reseed the generator after a fork() to avoid multiple generators
+///  with the same internal state.
+class BlumBlumShub : public PublicBlumBlumShub
+{
+public:
+	virtual ~BlumBlumShub() {}
+
+	/// \brief Construct a BlumBlumShub
+	/// \param p the first prime factor
+	/// \param q the second prime factor
+	/// \param seed the seed for the generator
+	/// \details Esure p and q are both primes congruent to 3 mod 4 and at least 512 bits long.
+	///  seed is the secret key and should be about as large as p*q.
+	BlumBlumShub(const Integer &p, const Integer &q, const Integer &seed);
+
+	bool IsRandomAccess() const {return true;}
+	void Seek(lword index);
+
+protected:
+	const Integer p, q;
+	const Integer x0;
+};
+
+NAMESPACE_END
+
+#endif