Botan::CurveGFp Class Reference

#include <curve_gfp.h>

Public Member Functions
	CurveGFp ()
	CurveGFp (const BigInt &p, const BigInt &a, const BigInt &b)
const BigInt &	get_a () const
const BigInt &	get_a_r () const
const BigInt &	get_b () const
const BigInt &	get_b_r () const
const BigInt &	get_p () const
word	get_p_dash () const
size_t	get_p_words () const
const BigInt &	get_r2 () const
bool	operator== (const CurveGFp &other) const
void	swap (CurveGFp &other)

Detailed Description

This class represents an elliptic curve over GF(p)

Definition at line 20 of file curve_gfp.h.

Constructor & Destructor Documentation

CurveGFp() [1/2]

Botan::CurveGFp::CurveGFp ( )

inline

Create an uninitialized CurveGFp

Definition at line 27 of file curve_gfp.h.

: p_words(0), p_dash(0) {}

Referenced by Botan::EC_Group::EC_Group(), operator==(), and swap().

CurveGFp() [2/2]

Botan::CurveGFp::CurveGFp ( const BigInt & p, const BigInt & a, const BigInt & b )

inline

Construct the elliptic curve E: y^2 = x^3 + ax + b over GF(p)

Parameters

p	prime number of the field
a	first coefficient
b	second coefficient

Definition at line 35 of file curve_gfp.h.

                                                                  :
         p(p), a(a), b(b), p_words(p.sig_words())
         {
         BigInt r(BigInt::Power2, p_words * BOTAN_MP_WORD_BITS);
 
         p_dash = (((r * inverse_mod(r, p)) - 1) / p).word_at(0);
 
         r2  = (r * r) % p;
         a_r = (a * r) % p;
         b_r = (b * r) % p;
         }

References Botan::inverse_mod(), and Botan::BigInt::Power2.

Member Function Documentation

get_a()

const BigInt & Botan::CurveGFp::get_a ( ) const

inline

Returns

curve coefficient a

Definition at line 53 of file curve_gfp.h.

{ return a; }

get_a_r()

const BigInt & Botan::CurveGFp::get_a_r ( ) const

inline

Returns

a * r mod p

Definition at line 74 of file curve_gfp.h.

{ return a_r; }

get_b()

const BigInt & Botan::CurveGFp::get_b ( ) const

inline

Returns

curve coefficient b

Definition at line 58 of file curve_gfp.h.

{ return b; }

get_b_r()

const BigInt & Botan::CurveGFp::get_b_r ( ) const

inline

Returns

b * r mod p

Definition at line 79 of file curve_gfp.h.

{ return b_r; }

get_p()

const BigInt & Botan::CurveGFp::get_p ( ) const

inline

Get prime modulus of the field of the curve

Returns

prime modulus of the field of the curve

Definition at line 64 of file curve_gfp.h.

{ return p; }

Referenced by Botan::EC2OSP().

get_p_dash()

word Botan::CurveGFp::get_p_dash ( ) const

inline

Returns

Montgomery parameter p-dash

Definition at line 84 of file curve_gfp.h.

{ return p_dash; }

get_p_words()

size_t Botan::CurveGFp::get_p_words ( ) const

inline

Returns

p.sig_words()

Definition at line 89 of file curve_gfp.h.

{ return p_words; }

get_r2()

const BigInt & Botan::CurveGFp::get_r2 ( ) const

inline

Returns

Montgomery parameter r^2 % p

Definition at line 69 of file curve_gfp.h.

{ return r2; }

operator==()

bool Botan::CurveGFp::operator== ( const CurveGFp & other ) const

inline

Equality operator

Parameters

other

curve to compare with

Returns

true iff this is the same curve as other

Definition at line 116 of file curve_gfp.h.

         {
         /*
         Relies on choice of R, but that is fixed by constructor based
         on size of p
         */
         return (p == other.p && a_r == other.a_r && b_r == other.b_r);
         }

References CurveGFp().

swap()

void Botan::CurveGFp::swap ( CurveGFp & other )

inline

swaps the states of *this and other, does not throw

Parameters

other

curve to swap values with

Definition at line 95 of file curve_gfp.h.

         {
         std::swap(p, other.p);
 
         std::swap(a, other.a);
         std::swap(b, other.b);
 
         std::swap(a_r, other.a_r);
         std::swap(b_r, other.b_r);
 
         std::swap(p_words, other.p_words);
 
         std::swap(r2, other.r2);
         std::swap(p_dash, other.p_dash);
         }

References CurveGFp(), and std::swap().

Referenced by std::swap< Botan::CurveGFp >().

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The documentation for this class was generated from the following file:

• src/math/ec_gfp/curve_gfp.h