127 lines
4.6 KiB
C
127 lines
4.6 KiB
C
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#ifndef CRYPTOPP_ECP_H
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#define CRYPTOPP_ECP_H
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#include "modarith.h"
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#include "eprecomp.h"
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#include "smartptr.h"
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#include "pubkey.h"
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NAMESPACE_BEGIN(CryptoPP)
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//! Elliptical Curve Point
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struct CRYPTOPP_DLL ECPPoint
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{
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ECPPoint() : identity(true) {}
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ECPPoint(const Integer &x, const Integer &y)
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: identity(false), x(x), y(y) {}
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bool operator==(const ECPPoint &t) const
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{return (identity && t.identity) || (!identity && !t.identity && x==t.x && y==t.y);}
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bool operator< (const ECPPoint &t) const
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{return identity ? !t.identity : (!t.identity && (x<t.x || (x==t.x && y<t.y)));}
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bool identity;
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Integer x, y;
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};
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CRYPTOPP_DLL_TEMPLATE_CLASS AbstractGroup<ECPPoint>;
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//! Elliptic Curve over GF(p), where p is prime
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class CRYPTOPP_DLL ECP : public AbstractGroup<ECPPoint>
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{
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public:
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typedef ModularArithmetic Field;
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typedef Integer FieldElement;
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typedef ECPPoint Point;
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ECP() {}
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ECP(const ECP &ecp, bool convertToMontgomeryRepresentation = false);
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ECP(const Integer &modulus, const FieldElement &a, const FieldElement &b)
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: m_fieldPtr(new Field(modulus)), m_a(a.IsNegative() ? modulus+a : a), m_b(b) {}
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// construct from BER encoded parameters
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// this constructor will decode and extract the the fields fieldID and curve of the sequence ECParameters
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ECP(BufferedTransformation &bt);
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// encode the fields fieldID and curve of the sequence ECParameters
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void DEREncode(BufferedTransformation &bt) const;
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bool Equal(const Point &P, const Point &Q) const;
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const Point& Identity() const;
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const Point& Inverse(const Point &P) const;
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bool InversionIsFast() const {return true;}
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const Point& Add(const Point &P, const Point &Q) const;
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const Point& Double(const Point &P) const;
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Point ScalarMultiply(const Point &P, const Integer &k) const;
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Point CascadeScalarMultiply(const Point &P, const Integer &k1, const Point &Q, const Integer &k2) const;
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void SimultaneousMultiply(Point *results, const Point &base, const Integer *exponents, unsigned int exponentsCount) const;
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Point Multiply(const Integer &k, const Point &P) const
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{return ScalarMultiply(P, k);}
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Point CascadeMultiply(const Integer &k1, const Point &P, const Integer &k2, const Point &Q) const
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{return CascadeScalarMultiply(P, k1, Q, k2);}
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bool ValidateParameters(RandomNumberGenerator &rng, unsigned int level=3) const;
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bool VerifyPoint(const Point &P) const;
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unsigned int EncodedPointSize(bool compressed = false) const
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{return 1 + (compressed?1:2)*GetField().MaxElementByteLength();}
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// returns false if point is compressed and not valid (doesn't check if uncompressed)
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bool DecodePoint(Point &P, BufferedTransformation &bt, size_t len) const;
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bool DecodePoint(Point &P, const byte *encodedPoint, size_t len) const;
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void EncodePoint(byte *encodedPoint, const Point &P, bool compressed) const;
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void EncodePoint(BufferedTransformation &bt, const Point &P, bool compressed) const;
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Point BERDecodePoint(BufferedTransformation &bt) const;
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void DEREncodePoint(BufferedTransformation &bt, const Point &P, bool compressed) const;
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Integer FieldSize() const {return GetField().GetModulus();}
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const Field & GetField() const {return *m_fieldPtr;}
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const FieldElement & GetA() const {return m_a;}
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const FieldElement & GetB() const {return m_b;}
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bool operator==(const ECP &rhs) const
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{return GetField() == rhs.GetField() && m_a == rhs.m_a && m_b == rhs.m_b;}
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private:
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clonable_ptr<Field> m_fieldPtr;
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FieldElement m_a, m_b;
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mutable Point m_R;
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};
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CRYPTOPP_DLL_TEMPLATE_CLASS DL_FixedBasePrecomputationImpl<ECP::Point>;
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CRYPTOPP_DLL_TEMPLATE_CLASS DL_GroupPrecomputation<ECP::Point>;
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template <class T> class EcPrecomputation;
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//! ECP precomputation
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template<> class EcPrecomputation<ECP> : public DL_GroupPrecomputation<ECP::Point>
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{
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public:
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typedef ECP EllipticCurve;
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// DL_GroupPrecomputation
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bool NeedConversions() const {return true;}
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Element ConvertIn(const Element &P) const
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{return P.identity ? P : ECP::Point(m_ec->GetField().ConvertIn(P.x), m_ec->GetField().ConvertIn(P.y));};
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Element ConvertOut(const Element &P) const
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{return P.identity ? P : ECP::Point(m_ec->GetField().ConvertOut(P.x), m_ec->GetField().ConvertOut(P.y));}
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const AbstractGroup<Element> & GetGroup() const {return *m_ec;}
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Element BERDecodeElement(BufferedTransformation &bt) const {return m_ec->BERDecodePoint(bt);}
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void DEREncodeElement(BufferedTransformation &bt, const Element &v) const {m_ec->DEREncodePoint(bt, v, false);}
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// non-inherited
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void SetCurve(const ECP &ec)
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{
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m_ec.reset(new ECP(ec, true));
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m_ecOriginal = ec;
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}
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const ECP & GetCurve() const {return *m_ecOriginal;}
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private:
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value_ptr<ECP> m_ec, m_ecOriginal;
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};
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NAMESPACE_END
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#endif
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