00001 #ifndef CRYPTOPP_ECP_H
00002 #define CRYPTOPP_ECP_H
00003
00004 #include "modarith.h"
00005 #include "eprecomp.h"
00006 #include "smartptr.h"
00007 #include "pubkey.h"
00008
00009 NAMESPACE_BEGIN(CryptoPP)
00010
00011
00012 struct ECPPoint
00013 {
00014 ECPPoint() : identity(true) {}
00015 ECPPoint(const Integer &x, const Integer &y)
00016 : identity(false), x(x), y(y) {}
00017
00018 bool operator==(const ECPPoint &t) const
00019 {return (identity && t.identity) || (!identity && !t.identity && x==t.x && y==t.y);}
00020 bool operator< (const ECPPoint &t) const
00021 {return identity ? !t.identity : (!t.identity && (x<t.x || (x==t.x && y<t.y)));}
00022
00023 bool identity;
00024 Integer x, y;
00025 };
00026
00027
00028 class ECP : public AbstractGroup<ECPPoint>
00029 {
00030 public:
00031 typedef ModularArithmetic Field;
00032 typedef Integer FieldElement;
00033 typedef ECPPoint Point;
00034
00035 ECP() {}
00036 ECP(const ECP &ecp, bool convertToMontgomeryRepresentation = false);
00037 ECP(const Integer &modulus, const FieldElement &a, const FieldElement &b)
00038 : m_fieldPtr(new Field(modulus)), m_a(a.IsNegative() ? modulus+a : a), m_b(b) {}
00039
00040
00041 ECP(BufferedTransformation &bt);
00042
00043
00044 void DEREncode(BufferedTransformation &bt) const;
00045
00046 bool Equal(const Point &P, const Point &Q) const;
00047 const Point& Identity() const;
00048 const Point& Inverse(const Point &P) const;
00049 bool InversionIsFast() const {return true;}
00050 const Point& Add(const Point &P, const Point &Q) const;
00051 const Point& Double(const Point &P) const;
00052 Point ScalarMultiply(const Point &P, const Integer &k) const;
00053 Point CascadeScalarMultiply(const Point &P, const Integer &k1, const Point &Q, const Integer &k2) const;
00054 void SimultaneousMultiply(Point *results, const Point &base, const Integer *exponents, unsigned int exponentsCount) const;
00055
00056 Point Multiply(const Integer &k, const Point &P) const
00057 {return ScalarMultiply(P, k);}
00058 Point CascadeMultiply(const Integer &k1, const Point &P, const Integer &k2, const Point &Q) const
00059 {return CascadeScalarMultiply(P, k1, Q, k2);}
00060
00061 bool ValidateParameters(RandomNumberGenerator &rng, unsigned int level=3) const;
00062 bool VerifyPoint(const Point &P) const;
00063
00064 unsigned int EncodedPointSize(bool compressed = false) const
00065 {return 1 + (compressed?1:2)*GetField().MaxElementByteLength();}
00066
00067 bool DecodePoint(Point &P, BufferedTransformation &bt, unsigned int len) const;
00068 bool DecodePoint(Point &P, const byte *encodedPoint, unsigned int len) const;
00069 void EncodePoint(byte *encodedPoint, const Point &P, bool compressed) const;
00070 void EncodePoint(BufferedTransformation &bt, const Point &P, bool compressed) const;
00071
00072 Point BERDecodePoint(BufferedTransformation &bt) const;
00073 void DEREncodePoint(BufferedTransformation &bt, const Point &P, bool compressed) const;
00074
00075 Integer FieldSize() const {return GetField().GetModulus();}
00076 const Field & GetField() const {return *m_fieldPtr;}
00077 const FieldElement & GetA() const {return m_a;}
00078 const FieldElement & GetB() const {return m_b;}
00079
00080 private:
00081 clonable_ptr<Field> m_fieldPtr;
00082 FieldElement m_a, m_b;
00083 mutable Point m_R;
00084 };
00085
00086 template <class T> class EcPrecomputation;
00087
00088
00089 template<> class EcPrecomputation<ECP> : public DL_GroupPrecomputation<ECP::Point>
00090 {
00091 public:
00092 typedef ECP EllipticCurve;
00093
00094
00095 bool NeedConversions() const {return true;}
00096 Element ConvertIn(const Element &P) const
00097 {return P.identity ? P : ECP::Point(m_ec->GetField().ConvertIn(P.x), m_ec->GetField().ConvertIn(P.y));};
00098 Element ConvertOut(const Element &P) const
00099 {return P.identity ? P : ECP::Point(m_ec->GetField().ConvertOut(P.x), m_ec->GetField().ConvertOut(P.y));}
00100 const AbstractGroup<Element> & GetGroup() const {return *m_ec;}
00101 Element BERDecodeElement(BufferedTransformation &bt) const {return m_ec->BERDecodePoint(bt);}
00102 void DEREncodeElement(BufferedTransformation &bt, const Element &v) const {m_ec->DEREncodePoint(bt, v, false);}
00103
00104
00105 void SetCurve(const ECP &ec);
00106 const ECP & GetCurve() const {return *m_ecOriginal;}
00107
00108 private:
00109 value_ptr<ECP> m_ec, m_ecOriginal;
00110 };
00111
00112 NAMESPACE_END
00113
00114 #endif