00001 #ifndef CRYPTOPP_EC2N_H
00002 #define CRYPTOPP_EC2N_H
00003
00004 #include "gf2n.h"
00005 #include "eprecomp.h"
00006 #include "smartptr.h"
00007 #include "pubkey.h"
00008
00009 NAMESPACE_BEGIN(CryptoPP)
00010
00011
00012 struct CRYPTOPP_DLL EC2NPoint
00013 {
00014 EC2NPoint() : identity(true) {}
00015 EC2NPoint(const PolynomialMod2 &x, const PolynomialMod2 &y)
00016 : identity(false), x(x), y(y) {}
00017
00018 bool operator==(const EC2NPoint &t) const
00019 {return (identity && t.identity) || (!identity && !t.identity && x==t.x && y==t.y);}
00020 bool operator< (const EC2NPoint &t) const
00021 {return identity ? !t.identity : (!t.identity && (x<t.x || (x==t.x && y<t.y)));}
00022
00023 bool identity;
00024 PolynomialMod2 x, y;
00025 };
00026
00027 CRYPTOPP_DLL_TEMPLATE_CLASS AbstractGroup<EC2NPoint>;
00028
00029
00030 class CRYPTOPP_DLL EC2N : public AbstractGroup<EC2NPoint>
00031 {
00032 public:
00033 typedef GF2NP Field;
00034 typedef Field::Element FieldElement;
00035 typedef EC2NPoint Point;
00036
00037 EC2N() {}
00038 EC2N(const Field &field, const Field::Element &a, const Field::Element &b)
00039 : m_field(field), m_a(a), m_b(b) {}
00040
00041
00042 EC2N(BufferedTransformation &bt);
00043
00044
00045 void DEREncode(BufferedTransformation &bt) const;
00046
00047 bool Equal(const Point &P, const Point &Q) const;
00048 const Point& Identity() const;
00049 const Point& Inverse(const Point &P) const;
00050 bool InversionIsFast() const {return true;}
00051 const Point& Add(const Point &P, const Point &Q) const;
00052 const Point& Double(const Point &P) const;
00053
00054 Point Multiply(const Integer &k, const Point &P) const
00055 {return ScalarMultiply(P, k);}
00056 Point CascadeMultiply(const Integer &k1, const Point &P, const Integer &k2, const Point &Q) const
00057 {return CascadeScalarMultiply(P, k1, Q, k2);}
00058
00059 bool ValidateParameters(RandomNumberGenerator &rng, unsigned int level=3) const;
00060 bool VerifyPoint(const Point &P) const;
00061
00062 unsigned int EncodedPointSize(bool compressed = false) const
00063 {return 1 + (compressed?1:2)*m_field->MaxElementByteLength();}
00064
00065 bool DecodePoint(Point &P, BufferedTransformation &bt, size_t len) const;
00066 bool DecodePoint(Point &P, const byte *encodedPoint, size_t len) const;
00067 void EncodePoint(byte *encodedPoint, const Point &P, bool compressed) const;
00068 void EncodePoint(BufferedTransformation &bt, const Point &P, bool compressed) const;
00069
00070 Point BERDecodePoint(BufferedTransformation &bt) const;
00071 void DEREncodePoint(BufferedTransformation &bt, const Point &P, bool compressed) const;
00072
00073 Integer FieldSize() const {return Integer::Power2(m_field->MaxElementBitLength());}
00074 const Field & GetField() const {return *m_field;}
00075 const FieldElement & GetA() const {return m_a;}
00076 const FieldElement & GetB() const {return m_b;}
00077
00078 bool operator==(const EC2N &rhs) const
00079 {return GetField() == rhs.GetField() && m_a == rhs.m_a && m_b == rhs.m_b;}
00080
00081 private:
00082 clonable_ptr<Field> m_field;
00083 FieldElement m_a, m_b;
00084 mutable Point m_R;
00085 };
00086
00087 CRYPTOPP_DLL_TEMPLATE_CLASS DL_FixedBasePrecomputationImpl<EC2N::Point>;
00088 CRYPTOPP_DLL_TEMPLATE_CLASS DL_GroupPrecomputation<EC2N::Point>;
00089
00090 template <class T> class EcPrecomputation;
00091
00092
00093 template<> class EcPrecomputation<EC2N> : public DL_GroupPrecomputation<EC2N::Point>
00094 {
00095 public:
00096 typedef EC2N EllipticCurve;
00097
00098
00099 const AbstractGroup<Element> & GetGroup() const {return m_ec;}
00100 Element BERDecodeElement(BufferedTransformation &bt) const {return m_ec.BERDecodePoint(bt);}
00101 void DEREncodeElement(BufferedTransformation &bt, const Element &v) const {m_ec.DEREncodePoint(bt, v, false);}
00102
00103
00104 void SetCurve(const EC2N &ec) {m_ec = ec;}
00105 const EC2N & GetCurve() const {return m_ec;}
00106
00107 private:
00108 EC2N m_ec;
00109 };
00110
00111 NAMESPACE_END
00112
00113 #endif