package elliptic
import "crypto/elliptic"
elliptic包实现了几条覆盖素数有限域的标准椭圆曲线。
Index
- type Curve
- func P224() Curve
- func P256() Curve
- func P384() Curve
- func P521() Curve
- type CurveParams
- func (curve *CurveParams) Add(x1, y1, x2, y2 *big.Int) (*big.Int, *big.Int)
- func (curve *CurveParams) Double(x1, y1 *big.Int) (*big.Int, *big.Int)
- func (curve *CurveParams) IsOnCurve(x, y *big.Int) bool
- func (curve *CurveParams) Params() *CurveParams
- func (curve *CurveParams) ScalarBaseMult(k []byte) (*big.Int, *big.Int)
- func (curve *CurveParams) ScalarMult(Bx, By *big.Int, k []byte) (*big.Int, *big.Int)
- func GenerateKey(curve Curve, rand io.Reader) (priv []byte, x, y *big.Int, err error)
- func Marshal(curve Curve, x, y *big.Int) []byte
- func Unmarshal(curve Curve, data []byte) (x, y *big.Int)
type Curve
type Curve interface {
// Params返回椭圆曲线的参数
Params() *CurveParams
// IsOnCurve判断一个点是否在椭圆曲线上
IsOnCurve(x, y *big.Int) bool
// 返回点(x1,y1)和点(x2,y2)相加的结果
Add(x1, y1, x2, y2 *big.Int) (x, y *big.Int)
// 返回2*(x,y),即(x,y)+(x,y)
Double(x1, y1 *big.Int) (x, y *big.Int)
// k是一个大端在前格式的数字,返回k*(Bx,By)
ScalarMult(x1, y1 *big.Int, k []byte) (x, y *big.Int)
// k是一个大端在前格式的数字,返回k*G,G是本椭圆曲线的基点
ScalarBaseMult(k []byte) (x, y *big.Int)
}
Curve代表一个短格式的Weierstrass椭圆曲线,其中a=-3。
Weierstrass椭圆曲线的格式:y**2 = x**3 + a*x + b
参见http://www.hyperelliptic.org/EFD/g1p/auto-shortw.html
func P224
func P224() Curve
返回一个实现了P-224的曲线。(参见FIPS 186-3, section D.2.2)
func P256
func P256() Curve
返回一个实现了P-256的曲线。(参见FIPS 186-3, section D.2.3)
func P384
func P384() Curve
返回一个实现了P-384的曲线。(参见FIPS 186-3, section D.2.4)
func P521
func P521() Curve
返回一个实现了P-512的曲线。(参见FIPS 186-3, section D.2.5)
type CurveParams
type CurveParams struct {
P *big.Int // 决定有限域的p的值(必须是素数)
N *big.Int // 基点的阶(必须是素数)
B *big.Int // 曲线公式的常量(B!=2)
Gx, Gy *big.Int // 基点的坐标
BitSize int // 决定有限域的p的字位数
}
CurveParams包含一个椭圆曲线的所有参数,也可提供一般的、非常数时间实现的椭圆曲线。
func (*CurveParams) Params
func (curve *CurveParams) Params() *CurveParams
func (*CurveParams) IsOnCurve
func (curve *CurveParams) IsOnCurve(x, y *big.Int) bool
func (*CurveParams) Add
func (curve *CurveParams) Add(x1, y1, x2, y2 *big.Int) (*big.Int, *big.Int)
func (*CurveParams) Double
func (curve *CurveParams) Double(x1, y1 *big.Int) (*big.Int, *big.Int)
func (*CurveParams) ScalarMult
func (curve *CurveParams) ScalarMult(Bx, By *big.Int, k []byte) (*big.Int, *big.Int)
func (*CurveParams) ScalarBaseMult
func (curve *CurveParams) ScalarBaseMult(k []byte) (*big.Int, *big.Int)
func GenerateKey
func GenerateKey(curve Curve, rand io.Reader) (priv []byte, x, y *big.Int, err error)
GenerateKey返回一个公钥/私钥对。priv是私钥,而(x,y)是公钥。密钥对是通过提供的随机数读取器来生成的,该io.Reader接口必须返回随机数据。
func Marshal
func Marshal(curve Curve, x, y *big.Int) []byte
Marshal将一个点编码为ANSI X9.62指定的格式。
func Unmarshal
func Unmarshal(curve Curve, data []byte) (x, y *big.Int)
将一个Marshal编码后的点还原;如果出错,x会被设为nil。