diff options
Diffstat (limited to 'src-cryptopp/ecp.h')
| -rw-r--r-- | src-cryptopp/ecp.h | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/src-cryptopp/ecp.h b/src-cryptopp/ecp.h new file mode 100644 index 0000000..d946be6 --- /dev/null +++ b/src-cryptopp/ecp.h @@ -0,0 +1,126 @@ +#ifndef CRYPTOPP_ECP_H +#define CRYPTOPP_ECP_H + +#include "modarith.h" +#include "eprecomp.h" +#include "smartptr.h" +#include "pubkey.h" + +NAMESPACE_BEGIN(CryptoPP) + +//! Elliptical Curve Point +struct CRYPTOPP_DLL ECPPoint +{ + ECPPoint() : identity(true) {} + ECPPoint(const Integer &x, const Integer &y) + : identity(false), x(x), y(y) {} + + bool operator==(const ECPPoint &t) const + {return (identity && t.identity) || (!identity && !t.identity && x==t.x && y==t.y);} + bool operator< (const ECPPoint &t) const + {return identity ? !t.identity : (!t.identity && (x<t.x || (x==t.x && y<t.y)));} + + bool identity; + Integer x, y; +}; + +CRYPTOPP_DLL_TEMPLATE_CLASS AbstractGroup<ECPPoint>; + +//! Elliptic Curve over GF(p), where p is prime +class CRYPTOPP_DLL ECP : public AbstractGroup<ECPPoint> +{ +public: + typedef ModularArithmetic Field; + typedef Integer FieldElement; + typedef ECPPoint Point; + + ECP() {} + ECP(const ECP &ecp, bool convertToMontgomeryRepresentation = false); + ECP(const Integer &modulus, const FieldElement &a, const FieldElement &b) + : m_fieldPtr(new Field(modulus)), m_a(a.IsNegative() ? modulus+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 + ECP(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 ScalarMultiply(const Point &P, const Integer &k) const; + Point CascadeScalarMultiply(const Point &P, const Integer &k1, const Point &Q, const Integer &k2) const; + void SimultaneousMultiply(Point *results, const Point &base, const Integer *exponents, unsigned int exponentsCount) 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)*GetField().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 GetField().GetModulus();} + const Field & GetField() const {return *m_fieldPtr;} + const FieldElement & GetA() const {return m_a;} + const FieldElement & GetB() const {return m_b;} + + bool operator==(const ECP &rhs) const + {return GetField() == rhs.GetField() && m_a == rhs.m_a && m_b == rhs.m_b;} + +private: + clonable_ptr<Field> m_fieldPtr; + FieldElement m_a, m_b; + mutable Point m_R; +}; + +CRYPTOPP_DLL_TEMPLATE_CLASS DL_FixedBasePrecomputationImpl<ECP::Point>; +CRYPTOPP_DLL_TEMPLATE_CLASS DL_GroupPrecomputation<ECP::Point>; + +template <class T> class EcPrecomputation; + +//! ECP precomputation +template<> class EcPrecomputation<ECP> : public DL_GroupPrecomputation<ECP::Point> +{ +public: + typedef ECP EllipticCurve; + + // DL_GroupPrecomputation + bool NeedConversions() const {return true;} + Element ConvertIn(const Element &P) const + {return P.identity ? P : ECP::Point(m_ec->GetField().ConvertIn(P.x), m_ec->GetField().ConvertIn(P.y));}; + Element ConvertOut(const Element &P) const + {return P.identity ? P : ECP::Point(m_ec->GetField().ConvertOut(P.x), m_ec->GetField().ConvertOut(P.y));} + 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 ECP &ec) + { + m_ec.reset(new ECP(ec, true)); + m_ecOriginal = ec; + } + const ECP & GetCurve() const {return *m_ecOriginal;} + +private: + value_ptr<ECP> m_ec, m_ecOriginal; +}; + +NAMESPACE_END + +#endif |