README
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Share Refresh
Proactive share refresh protocol following “Proactive Secret Sharing”. arties derive a zero-sum sharing and add it to their existing Feldman shares, obtaining fresh shares of the same secret.
Protocol Overview
- Zero Sharing: Run the HjKY zero-sharing subprotocol to generate a shared random value that sums to zero.
- Apply Offset: Each party adds its zero share to its current share and adds the corresponding verification vector to the existing one.
- Output: Refreshed shares and verification material represent the same secret under fresh randomness.
Implementation Notes
- Refreshing does not alter the underlying secret or access structure.
- The transcript domain separator binds the refresh session to the caller’s context.
ParticipantexposesRound1andRound2; use anetwork.Routerto exchange messages.
Usage
- Create a refresher with
NewParticipant(sessionID, shard, tape, prng). - Run
Round1and exchangeRound1Broadcast/Round1P2Pmessages. - Run
Round2with collected inputs to obtain the refreshed share and verification vector.
Documentation
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Overview ¶
Package refresh provides proactive share refresh protocol following “Proactive Secret Sharing”. arties derive a zero-sum sharing and add it to their existing Feldman shares, obtaining fresh shares of the same secret.
See README.md for details.
Index ¶
Constants ¶
This section is empty.
Variables ¶
var ( // ErrInvalidArgument indicates missing or inconsistent inputs. ErrInvalidArgument = errs.New("invalid argument") )
Functions ¶
This section is empty.
Types ¶
type Participant ¶
type Participant[G algebra.PrimeGroupElement[G, S], S algebra.PrimeFieldElement[S]] struct { // contains filtered or unexported fields }
Participant orchestrates share refresh using a zero-sum offset.
func NewParticipant ¶
func NewParticipant[G algebra.PrimeGroupElement[G, S], S algebra.PrimeFieldElement[S]](sid network.SID, shard *tsig.BaseShard[G, S], tape transcripts.Transcript, prng io.Reader) (*Participant[G, S], error)
NewParticipant constructs a shard refresher using the HjKy zero-sharing subprotocol.
func (*Participant[G, S]) Round1 ¶
func (p *Participant[G, S]) Round1() (broadcast *Round1Broadcast[G, S], unicasts network.OutgoingUnicasts[*Round1P2P[G, S]], err error)
Round1 runs the zero-sharing subprotocol to derive a refresh offset.
func (*Participant[G, S]) Round2 ¶
func (p *Participant[G, S]) Round2(r2b network.RoundMessages[*Round1Broadcast[G, S]], r2u network.RoundMessages[*Round1P2P[G, S]]) (share *feldman.Share[S], verification feldman.VerificationVector[G, S], err error)
Round2 finishes the refresh by adding the zero-share to the existing shard.
func (*Participant[G, S]) SharingID ¶
func (p *Participant[G, S]) SharingID() sharing.ID
SharingID returns the identifier of the refreshed shard.
type Round1Broadcast ¶
type Round1Broadcast[G algebra.PrimeGroupElement[G, S], S algebra.PrimeFieldElement[S]] = hjky.Round1Broadcast[G, S]
Round1Broadcast carries the public commitments for the zero-share offset.
type Round1P2P ¶
type Round1P2P[G algebra.PrimeGroupElement[G, S], S algebra.PrimeFieldElement[S]] = hjky.Round1P2P[G, S]
Round1P2P delivers the private zero-share offsets to each participant.
Source Files