refresh

Documentation

Overview

This file implements the key refresh protocol of [DKLs18](https://eprint.iacr.org/2018/499.pdf). The key refresh protocol is defined as follows:

1. Key Share: 1.1. alice generates k_A <-- F_q; writes it to merlin transcript. sends it to bob. 1.2. bob receives k_A and writes it to merlin transcript. generates k_B <-- F_q and writes it to merlin transcript. reads k out of merlin transcript. overwrites sk_B *= k. sends k_B to Alice. 1.3. alice writes k_B to merlin transcript. reads k from it. overwrites sk_A *= k^{-1}.
2. OT: Redo OT (as it is done in the DKG)

Index

• type Alice
  • func NewAlice(curve *curves.Curve, dkgOutput *dkg.AliceOutput) *Alice
  • func (alice *Alice) Output() *dkg.AliceOutput
  • func (alice *Alice) Round1RefreshGenerateSeed() curves.Scalar
  • func (alice *Alice) Round3RefreshMultiplyRound2Ot(input *RefreshRound2Output) ([]simplest.ReceiversMaskedChoices, error)
  • func (alice *Alice) Round5RefreshRound4Ot(challenge []simplest.OtChallenge) ([]simplest.OtChallengeResponse, error)
  • func (alice *Alice) Round7DkgRound6Ot(challengeOpenings []simplest.ChallengeOpening) error
• type Bob
  • func NewBob(curve *curves.Curve, dkgOutput *dkg.BobOutput) *Bob
  • func (bob *Bob) Output() *dkg.BobOutput
  • func (bob *Bob) Round2RefreshProduceSeedAndMultiplyAndStartOT(aliceSeed curves.Scalar) (*RefreshRound2Output, error)
  • func (bob *Bob) Round4RefreshRound3Ot(compressedReceiversMaskedChoice []simplest.ReceiversMaskedChoices) ([]simplest.OtChallenge, error)
  • func (bob *Bob) Round6RefreshRound5Ot(challengeResponses []simplest.OtChallengeResponse) ([]simplest.ChallengeOpening, error)
• type RefreshRound2Output

Types

type Alice

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

Alice struct encoding Alice's state during one execution of the overall signing algorithm. At the end of the joint computation, Alice will NOT obtain the signature.

func NewAlice

func NewAlice(curve *curves.Curve, dkgOutput *dkg.AliceOutput) *Alice

NewAliceRefresh creates a party that can participate in 2-of-2 key refresh.

func (*Alice) Output

func (alice *Alice) Output() *dkg.AliceOutput

func (*Alice) Round1RefreshGenerateSeed

func (alice *Alice) Round1RefreshGenerateSeed() curves.Scalar

func (*Alice) Round3RefreshMultiplyRound2Ot

func (alice *Alice) Round3RefreshMultiplyRound2Ot(input *RefreshRound2Output) ([]simplest.ReceiversMaskedChoices, error)

func (*Alice) Round5RefreshRound4Ot

func (alice *Alice) Round5RefreshRound4Ot(challenge []simplest.OtChallenge) ([]simplest.OtChallengeResponse, error)

func (*Alice) Round7DkgRound6Ot

func (alice *Alice) Round7DkgRound6Ot(challengeOpenings []simplest.ChallengeOpening) error

type Bob

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

Bob struct encoding Bob's state during one execution of the overall signing algorithm. At the end of the joint computation, Bob will obtain the signature.

func NewBob

func NewBob(curve *curves.Curve, dkgOutput *dkg.BobOutput) *Bob

NewBobRefresh creates a party that can participate in 2-of-2 key refresh.

func (*Bob) Output

func (bob *Bob) Output() *dkg.BobOutput

func (*Bob) Round2RefreshProduceSeedAndMultiplyAndStartOT

func (bob *Bob) Round2RefreshProduceSeedAndMultiplyAndStartOT(aliceSeed curves.Scalar) (*RefreshRound2Output, error)

func (*Bob) Round4RefreshRound3Ot

func (bob *Bob) Round4RefreshRound3Ot(compressedReceiversMaskedChoice []simplest.ReceiversMaskedChoices) ([]simplest.OtChallenge, error)

func (*Bob) Round6RefreshRound5Ot

func (bob *Bob) Round6RefreshRound5Ot(challengeResponses []simplest.OtChallengeResponse) ([]simplest.ChallengeOpening, error)

type RefreshRound2Output

type RefreshRound2Output struct {
	SeedOTRound1Output *schnorr.Proof
	BobMultiplier      curves.Scalar
}