1 files changed, 75 insertions, 0 deletions
diff --git a/CryptoPP/eprecomp.h b/CryptoPP/eprecomp.h
new file mode 100644
index 000000000..1f3256766
--- /dev/null
+++ b/CryptoPP/eprecomp.h
@@ -0,0 +1,75 @@
+#ifndef CRYPTOPP_EPRECOMP_H
+#define CRYPTOPP_EPRECOMP_H
+
+#include "integer.h"
+#include "algebra.h"
+#include <vector>
+
+NAMESPACE_BEGIN(CryptoPP)
+
+template <class T>
+class DL_GroupPrecomputation
+{
+public:
+	typedef T Element;
+
+	virtual bool NeedConversions() const {return false;}
+	virtual Element ConvertIn(const Element &v) const {return v;}
+	virtual Element ConvertOut(const Element &v) const {return v;}
+	virtual const AbstractGroup<Element> & GetGroup() const =0;
+	virtual Element BERDecodeElement(BufferedTransformation &bt) const =0;
+	virtual void DEREncodeElement(BufferedTransformation &bt, const Element &P) const =0;
+};
+
+template <class T>
+class DL_FixedBasePrecomputation
+{
+public:
+	typedef T Element;
+
+	virtual bool IsInitialized() const =0;
+	virtual void SetBase(const DL_GroupPrecomputation<Element> &group, const Element &base) =0;
+	virtual const Element & GetBase(const DL_GroupPrecomputation<Element> &group) const =0;
+	virtual void Precompute(const DL_GroupPrecomputation<Element> &group, unsigned int maxExpBits, unsigned int storage) =0;
+	virtual void Load(const DL_GroupPrecomputation<Element> &group, BufferedTransformation &storedPrecomputation) =0;
+	virtual void Save(const DL_GroupPrecomputation<Element> &group, BufferedTransformation &storedPrecomputation) const =0;
+	virtual Element Exponentiate(const DL_GroupPrecomputation<Element> &group, const Integer &exponent) const =0;
+	virtual Element CascadeExponentiate(const DL_GroupPrecomputation<Element> &group, const Integer &exponent, const DL_FixedBasePrecomputation<Element> &pc2, const Integer &exponent2) const =0;
+};
+
+template <class T>
+class DL_FixedBasePrecomputationImpl : public DL_FixedBasePrecomputation<T>
+{
+public:
+	typedef T Element;
+
+	DL_FixedBasePrecomputationImpl() : m_windowSize(0) {}
+
+	// DL_FixedBasePrecomputation
+	bool IsInitialized() const
+		{return !m_bases.empty();}
+	void SetBase(const DL_GroupPrecomputation<Element> &group, const Element &base);
+	const Element & GetBase(const DL_GroupPrecomputation<Element> &group) const
+		{return group.NeedConversions() ? m_base : m_bases[0];}
+	void Precompute(const DL_GroupPrecomputation<Element> &group, unsigned int maxExpBits, unsigned int storage);
+	void Load(const DL_GroupPrecomputation<Element> &group, BufferedTransformation &storedPrecomputation);
+	void Save(const DL_GroupPrecomputation<Element> &group, BufferedTransformation &storedPrecomputation) const;
+	Element Exponentiate(const DL_GroupPrecomputation<Element> &group, const Integer &exponent) const;
+	Element CascadeExponentiate(const DL_GroupPrecomputation<Element> &group, const Integer &exponent, const DL_FixedBasePrecomputation<Element> &pc2, const Integer &exponent2) const;
+
+private:
+	void PrepareCascade(const DL_GroupPrecomputation<Element> &group, std::vector<BaseAndExponent<Element> > &eb, const Integer &exponent) const;
+
+	Element m_base;
+	unsigned int m_windowSize;
+	Integer m_exponentBase;			// what base to represent the exponent in
+	std::vector<Element> m_bases;	// precalculated bases
+};
+
+NAMESPACE_END
+
+#ifdef CRYPTOPP_MANUALLY_INSTANTIATE_TEMPLATES
+#include "eprecomp.cpp"
+#endif
+
+#endif