Add ecpoint.h header file. Add EncodedPoint interface. Add documntation

1 files changed, 149 insertions, 0 deletions

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+// ecpoint.h - written and placed in the public domain by Jeffrey Walton

+//             Data structures moved from ecp.h and ec2n.h. Added EncodedPoint interface

+

+//! \file ecpoint.h

+//! \brief Classes for Elliptic Curve points

+//! \since Crypto++ 5.7

+

+#ifndef CRYPTOPP_ECPOINT_H

+#define CRYPTOPP_ECPOINT_H

+

+#include "cryptlib.h"

+#include "integer.h"

+#include "algebra.h"

+#include "gf2n.h"

+

+NAMESPACE_BEGIN(CryptoPP)

+

+//! \class ECPPoint

+//! \brief Elliptical Curve Point over GF(p), where p is prime

+//! \since Crypto++ 2.0

+struct CRYPTOPP_DLL ECPPoint

+{

+	virtual ~ECPPoint() {}

+

+	//! \brief Construct an ECPPoint

+	//! \details identity is set to <tt>true</tt>

+	ECPPoint() : identity(true) {}

+

+	//! \brief Construct an ECPPoint from coordinates

+	//! \details identity is set to <tt>false</tt>

+	ECPPoint(const Integer &x, const Integer &y)

+		: x(x), y(y), identity(false) {}

+

+	//! \brief Tests points for equality

+	//! \param t the other point

+	//! \returns true if the points are equal, false otherwise

+	bool operator==(const ECPPoint &t) const

+		{return (identity && t.identity) || (!identity && !t.identity && x==t.x && y==t.y);}

+

+	//! \brief Tests points for ordering

+	//! \param t the other point

+	//! \returns true if this point is less than other, false otherwise

+	bool operator< (const ECPPoint &t) const

+		{return identity ? !t.identity : (!t.identity && (x<t.x || (x==t.x && y<t.y)));}

+

+	Integer x, y;

+	bool identity;

+};

+

+CRYPTOPP_DLL_TEMPLATE_CLASS AbstractGroup<ECPPoint>;

+

+//! \class EC2NPoint

+//! \brief Elliptical Curve Point over GF(2^n)

+//! \since Crypto++ 2.0

+struct CRYPTOPP_DLL EC2NPoint

+{

+	virtual ~EC2NPoint() {}

+

+	//! \brief Construct an EC2NPoint

+	//! \details identity is set to <tt>true</tt>

+	EC2NPoint() : identity(true) {}

+

+	//! \brief Construct an EC2NPoint from coordinates

+	//! \details identity is set to <tt>false</tt>

+	EC2NPoint(const PolynomialMod2 &x, const PolynomialMod2 &y)

+		: x(x), y(y), identity(false) {}

+

+	//! \brief Tests points for equality

+	//! \param t the other point

+	//! \returns true if the points are equal, false otherwise

+	bool operator==(const EC2NPoint &t) const

+		{return (identity && t.identity) || (!identity && !t.identity && x==t.x && y==t.y);}

+

+	//! \brief Tests points for ordering

+	//! \param t the other point

+	//! \returns true if this point is less than other, false otherwise

+	bool operator< (const EC2NPoint &t) const

+		{return identity ? !t.identity : (!t.identity && (x<t.x || (x==t.x && y<t.y)));}

+

+	PolynomialMod2 x, y;

+	bool identity;

+};

+

+CRYPTOPP_DLL_TEMPLATE_CLASS AbstractGroup<EC2NPoint>;

+

+//! \class EncodedPoint

+//! \brief Abstract class for encoding and decoding ellicptic curve points

+//! \tparam Point ellicptic curve point

+//! \details EncodedPoint is an interface for encoding and decoding elliptic curve points.

+//!   The template parameter <tt>Point</tt> should be a class like ECP or EC2N.

+//! \since Crypto++ 5.7

+template <class Point>

+class EncodedPoint

+{

+public:

+	virtual ~EncodedPoint() {}

+

+	//! \brief Decodes an elliptic curve point

+	//! \param P point which is decoded

+	//! \param bt source BufferedTransformation

+	//! \param len number of bytes to read from the BufferedTransformation

+	//! \returns true if a point was decoded, false otherwise

+	virtual bool DecodePoint(Point &P, BufferedTransformation &bt, size_t len) const =0;

+

+	//! \brief Decodes an elliptic curve point

+	//! \param P point which is decoded

+	//! \param encodedPoint byte array with the encoded point

+	//! \param len the size of the array

+	//! \returns true if a point was decoded, false otherwise

+	virtual bool DecodePoint(Point &P, const byte *encodedPoint, size_t len) const =0;

+

+	//! \brief Verifies points on elliptic curve

+	//! \param P point to verify

+	//! \returns true if the point is valid, false otherwise

+	virtual bool VerifyPoint(const Point &P) const =0;

+

+	//! \brief Determines encoded point size

+	//! \param compressed flag indicating if the point is compressed

+	//! \returns the minimum number of bytes required to encode the point

+	virtual unsigned int EncodedPointSize(bool compressed = false) const =0;

+

+	//! \brief Encodes an elliptic curve point

+	//! \param P point which is decoded

+	//! \param encodedPoint byte array for the encoded point

+	//! \param compressed flag indicating if the point is compressed

+	//! \details <tt>encodedPoint</tt> must be at least EncodedPointSize() in length

+	virtual void EncodePoint(byte *encodedPoint, const Point &P, bool compressed) const =0;

+

+	//! \brief Encodes an elliptic curve point

+	//! \param bt target BufferedTransformation

+	//! \param P point which is encoded

+	//! \param compressed flag indicating if the point is compressed

+	virtual void EncodePoint(BufferedTransformation &bt, const Point &P, bool compressed) const =0;

+

+	//! \brief BER Decodes an elliptic curve point

+	//! \param bt source BufferedTransformation

+	//! \returns the decoded elliptic curve point

+	virtual Point BERDecodePoint(BufferedTransformation &bt) const =0;

+

+	//! \brief DER Encodes an elliptic curve point

+	//! \param bt target BufferedTransformation

+	//! \param P point which is encoded

+	//! \param compressed flag indicating if the point is compressed

+	virtual void DEREncodePoint(BufferedTransformation &bt, const Point &P, bool compressed) const =0;

+};

+

+NAMESPACE_END

+

+#endif  // CRYPTOPP_ECPOINT_H