elliptic

Documentation

Overview

Package elliptic implements several standard elliptic curves over prime fields.

Index

• type Curve
  • func P224() *Curve
  • func P256() *Curve
  • func P384() *Curve
  • func P521() *Curve
  • func (curve *Curve) Add(x1, y1, x2, y2 *big.Int) (*big.Int, *big.Int)
  • func (curve *Curve) Double(x1, y1 *big.Int) (*big.Int, *big.Int)
  • func (curve *Curve) GenerateKey(rand io.Reader) (priv []byte, x, y *big.Int, err os.Error)
  • func (curve *Curve) IsOnCurve(x, y *big.Int) bool
  • func (curve *Curve) Marshal(x, y *big.Int) []byte
  • func (curve *Curve) ScalarBaseMult(k []byte) (*big.Int, *big.Int)
  • func (curve *Curve) ScalarMult(Bx, By *big.Int, k []byte) (*big.Int, *big.Int)
  • func (curve *Curve) Unmarshal(data []byte) (x, y *big.Int)

Types

type Curve

type Curve struct {
	P       *big.Int // the order of the underlying field
	N       *big.Int // the order of the base point
	B       *big.Int // the constant of the curve equation
	Gx, Gy  *big.Int // (x,y) of the base point
	BitSize int      // the size of the underlying field
}

A Curve represents a short-form Weierstrass curve with a=-3. See http://www.hyperelliptic.org/EFD/g1p/auto-shortw.html

func P224

func P224() *Curve

P224 returns a Curve which implements P-224 (see FIPS 186-3, section D.2.2)

func P256

func P256() *Curve

P256 returns a Curve which implements P-256 (see FIPS 186-3, section D.2.3)

func P384

func P384() *Curve

P384 returns a Curve which implements P-384 (see FIPS 186-3, section D.2.4)

func P521

func P521() *Curve

P256 returns a Curve which implements P-521 (see FIPS 186-3, section D.2.5)

func (*Curve) Add

func (curve *Curve) Add(x1, y1, x2, y2 *big.Int) (*big.Int, *big.Int)

Add returns the sum of (x1,y1) and (x2,y2)

func (*Curve) Double

func (curve *Curve) Double(x1, y1 *big.Int) (*big.Int, *big.Int)

Double returns 2*(x,y)

func (*Curve) GenerateKey

func (curve *Curve) GenerateKey(rand io.Reader) (priv []byte, x, y *big.Int, err os.Error)

GenerateKey returns a public/private key pair. The private key is generated using the given reader, which must return random data.

func (*Curve) IsOnCurve

func (curve *Curve) IsOnCurve(x, y *big.Int) bool

IsOnCurve returns true if the given (x,y) lies on the curve.

func (*Curve) Marshal

func (curve *Curve) Marshal(x, y *big.Int) []byte

Marshal converts a point into the form specified in section 4.3.6 of ANSI X9.62.

func (*Curve) ScalarBaseMult

func (curve *Curve) ScalarBaseMult(k []byte) (*big.Int, *big.Int)

ScalarBaseMult returns k*G, where G is the base point of the group and k is an integer in big-endian form.

func (*Curve) ScalarMult

func (curve *Curve) ScalarMult(Bx, By *big.Int, k []byte) (*big.Int, *big.Int)

ScalarMult returns k*(Bx,By) where k is a number in big-endian form.

func (*Curve) Unmarshal

func (curve *Curve) Unmarshal(data []byte) (x, y *big.Int)

Unmarshal converts a point, serialized by Marshal, into an x, y pair. On error, x = nil.