group

Documentation

Overview

Package group provides prime-order groups based on elliptic curves.

Index

• Variables
• func HashToField(u []big.Int, b []byte, e expander.Expander, p *big.Int, L uint)
• type Element
• type Group
• type Params
• type Scalar

Variables

var (
	ErrType      = errors.New("type mismatch")
	ErrUnmarshal = errors.New("error unmarshaling")
)

Functions

func HashToField

func HashToField(u []big.Int, b []byte, e expander.Expander, p *big.Int, L uint)

HashToField generates a set of elements {u1,..., uN} = Hash(b) where each u in GF(p) and L is the security parameter.

Types

type Element

type Element interface {
	IsIdentity() bool
	IsEqual(Element) bool
	Add(Element, Element) Element
	Dbl(Element) Element
	Neg(Element) Element
	Mul(Element, Scalar) Element
	MulGen(Scalar) Element
	encoding.BinaryMarshaler
	encoding.BinaryUnmarshaler
	MarshalBinaryCompress() ([]byte, error)
}

Element represents an abstract element of a prime-order group.

type Group

type Group interface {
	Params() *Params // Params returns parameters for the group
	NewElement() Element
	NewScalar() Scalar
	Identity() Element
	Generator() Element
	Order() Scalar
	RandomElement(io.Reader) Element
	RandomScalar(io.Reader) Scalar
	RandomNonZeroScalar(io.Reader) Scalar
	HashToElement(data, dst []byte) Element
	HashToElementNonUniform(b, dst []byte) Element
	HashToScalar(data, dst []byte) Scalar
}

Group represents a prime-order group based on elliptic curves.

var (
	// P256 is the group generated by P-256 elliptic curve.
	P256 Group = wG{elliptic.P256()}
	// P384 is the group generated by P-384 elliptic curve.
	P384 Group = wG{p384.P384()}
	// P521 is the group generated by P-521 elliptic curve.
	P521 Group = wG{elliptic.P521()}
)

var (
	// Ristretto255 is a quotient group generated from edwards25519 curve.
	Ristretto255 Group = ristrettoGroup{}
)

type Params

type Params struct {
	ElementLength           uint // Length in bytes of an element.
	CompressedElementLength uint // Length in bytes of a compressed element.
	ScalarLength            uint // Length in bytes of a scalar.
}

type Scalar

type Scalar interface {
	IsEqual(Scalar) bool
	SetUint64(uint64)
	Add(Scalar, Scalar) Scalar
	Sub(Scalar, Scalar) Scalar
	Mul(Scalar, Scalar) Scalar
	Neg(Scalar) Scalar
	Inv(Scalar) Scalar
	encoding.BinaryMarshaler
	encoding.BinaryUnmarshaler
}

Scalar represents an integer scalar.