share

Documentation

Overview

Package share implements Shamir secret sharing and polynomial commitments. Shamir's scheme allows you to split a secret value into multiple parts, so called shares, by evaluating a secret sharing polynomial at certain indices. The shared secret can only be reconstructed (via Lagrange interpolation) if a threshold of the participants provide their shares. A polynomial commitment scheme allows a committer to commit to a secret sharing polynomial so that a verifier can check the claimed evaluations of the committed polynomial. Both schemes of this package are core building blocks for more advanced secret sharing techniques.

Index

• func RecoverCommit(g group.Group, shares []*PubShare, t, n int) (group.Point, error)
• type PriPoly
  • func NewPriPoly(grp group.Group, t int, s group.Scalar, rand cipher.Stream) *PriPoly
  • func (p *PriPoly) Eval(i int) *PriShare
  • func (p *PriPoly) Secret() group.Scalar
  • func (p *PriPoly) Shares(n int) []*PriShare
  • func (p *PriPoly) String() string
• type PriShare
  • func (p *PriShare) String() string
• type PubShare

Functions

func RecoverCommit

func RecoverCommit(g group.Group, shares []*PubShare, t, n int) (group.Point, error)

RecoverCommit reconstructs the secret commitment p(0) from a list of public shares using Lagrange interpolation.

Types

type PriPoly

type PriPoly struct {
	// contains filtered or unexported fields
}

PriPoly represents a secret sharing polynomial.

func NewPriPoly

func NewPriPoly(grp group.Group, t int, s group.Scalar, rand cipher.Stream) *PriPoly

NewPriPoly creates a new secret sharing polynomial using the provided cryptographic group, the secret sharing threshold t, and the secret to be shared s. If s is nil, a new s is chosen using the provided randomness stream rand.

func (*PriPoly) Eval

func (p *PriPoly) Eval(i int) *PriShare

Eval computes the private share v = p(i).

func (*PriPoly) Secret

func (p *PriPoly) Secret() group.Scalar

Secret returns the shared secret p(0), i.e., the constant term of the polynomial.

func (*PriPoly) Shares

func (p *PriPoly) Shares(n int) []*PriShare

Shares creates a list of n private shares p(1),...,p(n).

func (*PriPoly) String

func (p *PriPoly) String() string

type PriShare

type PriShare struct {
	I int          // Index of the private share
	V group.Scalar // Value of the private share
}

PriShare represents a private share.

func (*PriShare) String

func (p *PriShare) String() string

type PubShare

type PubShare struct {
	I int         // Index of the public share
	V group.Point // Value of the public share
}

PubShare represents a public share.