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/*
* Elliptic curves over GF(p)
*
* (C) 2007 Martin Doering, Christoph Ludwig, Falko Strenzke
* 2010 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/
#ifndef BOTAN_GFP_CURVE_H__
#define BOTAN_GFP_CURVE_H__
#include <botan/bigint.h>
#include <botan/gfp_element.h>
#include <iosfwd>
namespace Botan {
/**
* This class represents an elliptic curve over GF(p)
*/
class BOTAN_DLL CurveGFp
{
public:
/**
* Construct the elliptic curve E: y^2 = x^3 + ax + b over GF(p)
* @param a first coefficient
* @param b second coefficient
* @param p prime number of the field
*/
CurveGFp(const GFpElement& a, const GFpElement& b,
const BigInt& p);
// CurveGFp(const CurveGFp& other) = default;
// CurveGFp& operator=(const CurveGFp& other) = default;
// getters
/**
* Get coefficient a
* @result coefficient a
*/
const GFpElement& get_a() const { return mA; }
/**
* Get coefficient b
* @result coefficient b
*/
const GFpElement& get_b() const { return mB; }
/**
* Get the GFpElement coefficient a transformed
* to its m-residue. This can be used for efficency reasons: the curve
* stores the transformed version after the first invocation of this
* function.
* @result the coefficient a, transformed to its m-residue
*/
const GFpElement& get_mres_a() const { return mres_a; }
/**
* Get the GFpElement coefficient b transformed
* to its m-residue. This can be used for efficency reasons: the curve
* stores the transformed version after the first invocation of this
* function.
* @result the coefficient b, transformed to its m-residue
*/
const GFpElement& get_mres_b() const { return mres_b; }
/**
* Get the GFpElement 1 transformed
* to its m-residue. This can be used for efficency reasons: the curve
* stores the transformed version after the first invocation of this
* function.
* @result the GFpElement 1, transformed to its m-residue
*/
const GFpElement& get_mres_one() { return mres_one; }
/**
* Get prime modulus of the field of the curve
* @result prime modulus of the field of the curve
*/
const BigInt& get_p() const { return modulus.get_p(); }
/**
* swaps the states of *this and other, does not throw
* @param other The curve to swap values with
*/
void swap(CurveGFp& other);
private:
GFpModulus modulus;
GFpElement mA;
GFpElement mB;
GFpElement mres_a, mres_b, mres_one;
};
// relational operators
bool operator==(const CurveGFp& lhs, const CurveGFp& rhs);
inline bool operator!=(const CurveGFp& lhs, const CurveGFp& rhs)
{
return !(lhs == rhs);
}
// io operators
std::ostream& operator<<(std::ostream& output, const CurveGFp& elem);
// swaps the states of curve1 and curve2, does not throw!
// cf. Meyers, Item 25
inline
void swap(CurveGFp& curve1, CurveGFp& curve2)
{
curve1.swap(curve2);
}
} // namespace Botan
namespace std {
// swaps the states of curve1 and curve2, does not throw!
// cf. Meyers, Item 25
template<> inline
void swap<Botan::CurveGFp>(Botan::CurveGFp& curve1,
Botan::CurveGFp& curve2)
{
curve1.swap(curve2);
}
} // namespace std
#endif
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