Documentation
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Overview ¶
Package refresh implements the key-share refresh protocol for DKLS19.
The refresh protocol lets Alice and Bob rotate their additive key shares and re-seed the correlated OT material without changing the joint public key.
Protocol outline (additive refresh, Silent OT variant):
- Alice samples k_A ← F_q, writes it to the transcript, and sends it to Bob.
- Bob appends k_A, samples k_B, derives the common addend k, updates sk_B ← sk_B + k. Generates new silent-OT DH key + Schnorr proof. Sends k_B + OTProof.
- Alice appends k_B, derives k, updates sk_A ← sk_A − k, verifies OTProof, and stores her new ReceiverOutput. No further rounds.
Invariant: sk_A' + sk_B' = (sk_A − k) + (sk_B + k) = sk_A + sk_B = x, so the joint public key Q = (sk_A + sk_B)·G is unchanged.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Alice ¶
type Alice struct {
// contains filtered or unexported fields
}
Alice holds Alice's mutable state during one refresh execution.
func NewAlice ¶
func NewAlice(curve *curves.Curve, dkgOutput *dkg.AliceOutput) *Alice
NewAlice creates an Alice refresh instance from existing DKG output. Returns nil if curve or dkgOutput is nil.
func (*Alice) Output ¶
func (alice *Alice) Output() *dkg.AliceOutput
Output returns Alice's refreshed DKG output. Returns nil if the refresh protocol has not yet finished.
func (*Alice) Round1AliceAddend ¶ added in v1.0.1
Round1AliceAddend is Alice's opening move. She samples k_A ← F_q, appends it to the transcript, and sends it to Bob.
func (*Alice) Round3AliceUpdateAndOT ¶
func (alice *Alice) Round3AliceUpdateAndOT(r2 *RefreshRound2Output) error
Round3AliceUpdateAndOT is Alice's final step. She appends k_B, derives k, updates her key share as sk_A ← sk_A − k, verifies Bob's Silent OT Schnorr proof, and stores her new ReceiverOutput.
type Bob ¶
type Bob struct {
// contains filtered or unexported fields
}
Bob holds Bob's mutable state during one refresh execution.
func NewBob ¶
NewBob creates a Bob refresh instance from existing DKG output. Returns nil if curve or dkgOutput is nil.
func (*Bob) Output ¶
Output returns Bob's refreshed DKG output. Returns nil if the refresh protocol has not yet finished.
func (*Bob) Round2BobAddendAndOT ¶ added in v1.0.1
func (bob *Bob) Round2BobAddendAndOT(kA curves.Scalar) (*RefreshRound2Output, error)
Round2BobAddendAndOT is Bob's response. Bob appends k_A, samples k_B, derives the common addend k, updates his key share as sk_B ← sk_B + k, and generates the new silent-OT DH key pair.
type RefreshRound2Output ¶
type RefreshRound2Output struct {
// OTProof is the Schnorr proof of Bob's silent-OT DH secret b.
OTProof *schnorr.Proof
// BobAddend is k_B, Bob's random contribution to the refresh transcript.
BobAddend curves.Scalar
}
RefreshRound2Output is Bob's message to Alice in the refresh protocol.
Source Files