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 CRYPTOPP_DLL 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 CRYPTOPP_DLL_TEMPLATE_CLASS AbstractGroup<ECPPoint>;
00028
00029
00030 class CRYPTOPP_DLL ECP : public AbstractGroup<ECPPoint>
00031 {
00032 public:
00033 typedef ModularArithmetic Field;
00034 typedef Integer FieldElement;
00035 typedef ECPPoint Point;
00036
00037 ECP() {}
00038 ECP(const ECP &ecp, bool convertToMontgomeryRepresentation = false);
00039 ECP(const Integer &modulus, const FieldElement &a, const FieldElement &b)
00040 : m_fieldPtr(new Field(modulus)), m_a(a.IsNegative() ? modulus+a : a), m_b(b) {}
00041
00042
00043 ECP(BufferedTransformation &bt);
00044
00045
00046 void DEREncode(BufferedTransformation &bt) const;
00047
00048 bool Equal(const Point &P, const Point &Q) const;
00049 const Point& Identity() const;
00050 const Point& Inverse(const Point &P) const;
00051 bool InversionIsFast() const {return true;}
00052 const Point& Add(const Point &P, const Point &Q) const;
00053 const Point& Double(const Point &P) const;
00054 Point ScalarMultiply(const Point &P, const Integer &k) const;
00055 Point CascadeScalarMultiply(const Point &P, const Integer &k1, const Point &Q, const Integer &k2) const;
00056 void SimultaneousMultiply(Point *results, const Point &base, const Integer *exponents, unsigned int exponentsCount) const;
00057
00058 Point Multiply(const Integer &k, const Point &P) const
00059 {return ScalarMultiply(P, k);}
00060 Point CascadeMultiply(const Integer &k1, const Point &P, const Integer &k2, const Point &Q) const
00061 {return CascadeScalarMultiply(P, k1, Q, k2);}
00062
00063 bool ValidateParameters(RandomNumberGenerator &rng, unsigned int level=3) const;
00064 bool VerifyPoint(const Point &P) const;
00065
00066 unsigned int EncodedPointSize(bool compressed = false) const
00067 {return 1 + (compressed?1:2)*GetField().MaxElementByteLength();}
00068
00069 bool DecodePoint(Point &P, BufferedTransformation &bt, size_t len) const;
00070 bool DecodePoint(Point &P, const byte *encodedPoint, size_t len) const;
00071 void EncodePoint(byte *encodedPoint, const Point &P, bool compressed) const;
00072 void EncodePoint(BufferedTransformation &bt, const Point &P, bool compressed) const;
00073
00074 Point BERDecodePoint(BufferedTransformation &bt) const;
00075 void DEREncodePoint(BufferedTransformation &bt, const Point &P, bool compressed) const;
00076
00077 Integer FieldSize() const {return GetField().GetModulus();}
00078 const Field & GetField() const {return *m_fieldPtr;}
00079 const FieldElement & GetA() const {return m_a;}
00080 const FieldElement & GetB() const {return m_b;}
00081
00082 bool operator==(const ECP &rhs) const
00083 {return GetField() == rhs.GetField() && m_a == rhs.m_a && m_b == rhs.m_b;}
00084
00085 private:
00086 clonable_ptr<Field> m_fieldPtr;
00087 FieldElement m_a, m_b;
00088 mutable Point m_R;
00089 };
00090
00091 CRYPTOPP_DLL_TEMPLATE_CLASS DL_FixedBasePrecomputationImpl<ECP::Point>;
00092 CRYPTOPP_DLL_TEMPLATE_CLASS DL_GroupPrecomputation<ECP::Point>;
00093
00094 template <class T> class EcPrecomputation;
00095
00096
00097 template<> class EcPrecomputation<ECP> : public DL_GroupPrecomputation<ECP::Point>
00098 {
00099 public:
00100 typedef ECP EllipticCurve;
00101
00102
00103 bool NeedConversions() const {return true;}
00104 Element ConvertIn(const Element &P) const
00105 {return P.identity ? P : ECP::Point(m_ec->GetField().ConvertIn(P.x), m_ec->GetField().ConvertIn(P.y));};
00106 Element ConvertOut(const Element &P) const
00107 {return P.identity ? P : ECP::Point(m_ec->GetField().ConvertOut(P.x), m_ec->GetField().ConvertOut(P.y));}
00108 const AbstractGroup<Element> & GetGroup() const {return *m_ec;}
00109 Element BERDecodeElement(BufferedTransformation &bt) const {return m_ec->BERDecodePoint(bt);}
00110 void DEREncodeElement(BufferedTransformation &bt, const Element &v) const {m_ec->DEREncodePoint(bt, v, false);}
00111
00112
00113 void SetCurve(const ECP &ec)
00114 {
00115 m_ec.reset(new ECP(ec, true));
00116 m_ecOriginal = ec;
00117 }
00118 const ECP & GetCurve() const {return *m_ecOriginal;}
00119
00120 private:
00121 value_ptr<ECP> m_ec, m_ecOriginal;
00122 };
00123
00124 NAMESPACE_END
00125
00126 #endif