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bitcoin-bitcoin-core/group.h
2013-03-31 03:06:16 +02:00

113 lines
2.6 KiB
C++

#ifndef _SECP256K1_GROUP_
#define _SECP256K1_GROUP_
#include <string>
#include "num.h"
#include "field.h"
namespace secp256k1 {
class GroupElemJac;
/** Defines a point on the secp256k1 curve (y^2 = x^3 + 7) */
class GroupElem {
protected:
bool fInfinity;
secp256k1_fe_t x;
secp256k1_fe_t y;
public:
/** Creates the point at infinity */
GroupElem();
/** Creates the point with given affine coordinates */
GroupElem(const secp256k1_fe_t &xin, const secp256k1_fe_t &yin);
/** Checks whether this is the point at infinity */
bool IsInfinity() const;
void SetNeg(const GroupElem &p);
void GetX(secp256k1_fe_t &xout);
void GetY(secp256k1_fe_t &yout);
std::string ToString() const;
void SetJac(GroupElemJac &jac);
friend class GroupElemJac;
};
/** Represents a point on the secp256k1 curve, with jacobian coordinates */
class GroupElemJac : private GroupElem {
protected:
secp256k1_fe_t z;
public:
/** Creates the point at infinity */
GroupElemJac();
/** Creates the point with given affine coordinates */
GroupElemJac(const secp256k1_fe_t &xin, const secp256k1_fe_t &yin);
GroupElemJac(const GroupElem &in);
void SetJac(const GroupElemJac &jac);
void SetAffine(const GroupElem &aff);
/** Checks whether this is a non-infinite point on the curve */
bool IsValid() const;
/** Returns the affine coordinates of this point */
void GetAffine(GroupElem &aff);
void GetX(secp256k1_fe_t &xout);
void GetY(secp256k1_fe_t &yout);
bool IsInfinity() const;
void SetNeg(const GroupElemJac &p);
/** Sets this point to have a given X coordinate & given Y oddness */
void SetCompressed(const secp256k1_fe_t &xin, bool fOdd);
/** Sets this point to be the EC double of another */
void SetDouble(const GroupElemJac &p);
/** Sets this point to be the EC addition of two others */
void SetAdd(const GroupElemJac &p, const GroupElemJac &q);
/** Sets this point to be the EC addition of two others (one of which is in affine coordinates) */
void SetAdd(const GroupElemJac &p, const GroupElem &q);
std::string ToString() const;
void SetMulLambda(const GroupElemJac &p);
};
class GroupConstants {
private:
secp256k1_fe_t g_x;
secp256k1_fe_t g_y;
public:
secp256k1_num_t order;
GroupElem g;
secp256k1_fe_t beta;
secp256k1_num_t lambda, a1b2, b1, a2;
GroupConstants();
~GroupConstants();
};
const GroupConstants &GetGroupConst();
void SplitExp(const secp256k1_num_t &exp, secp256k1_num_t &exp1, secp256k1_num_t &exp2);
}
#endif