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Diffstat (limited to 'src-cryptopp/ec2n.h')
| -rw-r--r-- | src-cryptopp/ec2n.h | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/src-cryptopp/ec2n.h b/src-cryptopp/ec2n.h new file mode 100644 index 0000000..ae4007c --- /dev/null +++ b/src-cryptopp/ec2n.h @@ -0,0 +1,113 @@ +#ifndef CRYPTOPP_EC2N_H +#define CRYPTOPP_EC2N_H + +#include "gf2n.h" +#include "eprecomp.h" +#include "smartptr.h" +#include "pubkey.h" + +NAMESPACE_BEGIN(CryptoPP) + +//! Elliptic Curve Point +struct CRYPTOPP_DLL EC2NPoint +{ + EC2NPoint() : identity(true) {} + EC2NPoint(const PolynomialMod2 &x, const PolynomialMod2 &y) + : identity(false), x(x), y(y) {} + + bool operator==(const EC2NPoint &t) const + {return (identity && t.identity) || (!identity && !t.identity && x==t.x && y==t.y);} + bool operator< (const EC2NPoint &t) const + {return identity ? !t.identity : (!t.identity && (x<t.x || (x==t.x && y<t.y)));} + + bool identity; + PolynomialMod2 x, y; +}; + +CRYPTOPP_DLL_TEMPLATE_CLASS AbstractGroup<EC2NPoint>; + +//! Elliptic Curve over GF(2^n) +class CRYPTOPP_DLL EC2N : public AbstractGroup<EC2NPoint> +{ +public: + typedef GF2NP Field; + typedef Field::Element FieldElement; + typedef EC2NPoint Point; + + EC2N() {} + EC2N(const Field &field, const Field::Element &a, const Field::Element &b) + : m_field(field), m_a(a), m_b(b) {} + // construct from BER encoded parameters + // this constructor will decode and extract the the fields fieldID and curve of the sequence ECParameters + EC2N(BufferedTransformation &bt); + + // encode the fields fieldID and curve of the sequence ECParameters + void DEREncode(BufferedTransformation &bt) const; + + bool Equal(const Point &P, const Point &Q) const; + const Point& Identity() const; + const Point& Inverse(const Point &P) const; + bool InversionIsFast() const {return true;} + const Point& Add(const Point &P, const Point &Q) const; + const Point& Double(const Point &P) const; + + Point Multiply(const Integer &k, const Point &P) const + {return ScalarMultiply(P, k);} + Point CascadeMultiply(const Integer &k1, const Point &P, const Integer &k2, const Point &Q) const + {return CascadeScalarMultiply(P, k1, Q, k2);} + + bool ValidateParameters(RandomNumberGenerator &rng, unsigned int level=3) const; + bool VerifyPoint(const Point &P) const; + + unsigned int EncodedPointSize(bool compressed = false) const + {return 1 + (compressed?1:2)*m_field->MaxElementByteLength();} + // returns false if point is compressed and not valid (doesn't check if uncompressed) + bool DecodePoint(Point &P, BufferedTransformation &bt, size_t len) const; + bool DecodePoint(Point &P, const byte *encodedPoint, size_t len) const; + void EncodePoint(byte *encodedPoint, const Point &P, bool compressed) const; + void EncodePoint(BufferedTransformation &bt, const Point &P, bool compressed) const; + + Point BERDecodePoint(BufferedTransformation &bt) const; + void DEREncodePoint(BufferedTransformation &bt, const Point &P, bool compressed) const; + + Integer FieldSize() const {return Integer::Power2(m_field->MaxElementBitLength());} + const Field & GetField() const {return *m_field;} + const FieldElement & GetA() const {return m_a;} + const FieldElement & GetB() const {return m_b;} + + bool operator==(const EC2N &rhs) const + {return GetField() == rhs.GetField() && m_a == rhs.m_a && m_b == rhs.m_b;} + +private: + clonable_ptr<Field> m_field; + FieldElement m_a, m_b; + mutable Point m_R; +}; + +CRYPTOPP_DLL_TEMPLATE_CLASS DL_FixedBasePrecomputationImpl<EC2N::Point>; +CRYPTOPP_DLL_TEMPLATE_CLASS DL_GroupPrecomputation<EC2N::Point>; + +template <class T> class EcPrecomputation; + +//! EC2N precomputation +template<> class EcPrecomputation<EC2N> : public DL_GroupPrecomputation<EC2N::Point> +{ +public: + typedef EC2N EllipticCurve; + + // DL_GroupPrecomputation + const AbstractGroup<Element> & GetGroup() const {return m_ec;} + Element BERDecodeElement(BufferedTransformation &bt) const {return m_ec.BERDecodePoint(bt);} + void DEREncodeElement(BufferedTransformation &bt, const Element &v) const {m_ec.DEREncodePoint(bt, v, false);} + + // non-inherited + void SetCurve(const EC2N &ec) {m_ec = ec;} + const EC2N & GetCurve() const {return m_ec;} + +private: + EC2N m_ec; +}; + +NAMESPACE_END + +#endif |