Lux Docs

Scheme

The top-level factory interface. Every threshold implementation must satisfy Scheme.

type Scheme interface {
    ID() SchemeID
    Name() string
    KeyShareSize() int
    SignatureShareSize() int
    SignatureSize() int
    PublicKeySize() int
    NewDKG(config DKGConfig) (DKG, error)
    NewTrustedDealer(config DealerConfig) (TrustedDealer, error)
    NewSigner(share KeyShare) (Signer, error)
    NewAggregator(groupKey PublicKey) (Aggregator, error)
    NewVerifier(groupKey PublicKey) (Verifier, error)
    ParseKeyShare(data []byte) (KeyShare, error)
    ParsePublicKey(data []byte) (PublicKey, error)
    ParseSignatureShare(data []byte) (SignatureShare, error)
    ParseSignature(data []byte) (Signature, error)
}

DKG (Distributed Key Generation)

Multi-round protocol where parties collaboratively generate key shares without any single party knowing the full secret.

type DKG interface {
    Round1(ctx context.Context) (DKGMessage, error)
    Round2(ctx context.Context, round1Messages map[int]DKGMessage) (DKGMessage, error)
    Round3(ctx context.Context, round2Messages map[int]DKGMessage) (KeyShare, error)
    NumRounds() int
    GroupKey() PublicKey
}

KeyShare

A party's portion of the threshold secret key.

type KeyShare interface {
    Index() int
    GroupKey() PublicKey
    PublicShare() []byte
    Threshold() int
    TotalParties() int
    Bytes() []byte
    SchemeID() SchemeID
}

Signer

Creates signature shares. For multi-round schemes, NonceGen must be called before SignShare.

type Signer interface {
    Index() int
    PublicShare() []byte
    NonceGen(ctx context.Context) (NonceCommitment, NonceState, error)
    SignShare(ctx context.Context, message []byte, signers []int, nonce NonceState) (SignatureShare, error)
    KeyShare() KeyShare
}

Aggregator

Combines t+1 signature shares into a single valid signature.

type Aggregator interface {
    Aggregate(ctx context.Context, message []byte, shares []SignatureShare, commitments []NonceCommitment) (Signature, error)
    VerifyShare(message []byte, share SignatureShare, publicShare []byte) error
    GroupKey() PublicKey
}

Verifier

Checks a final threshold signature against the group public key.

type Verifier interface {
    Verify(message []byte, signature Signature) bool
    VerifyBytes(message, signature []byte) bool
    GroupKey() PublicKey
}

Configuration

type DKGConfig struct {
    Threshold    int       // Minimum signers required (t)
    TotalParties int       // Total parties (n)
    PartyIndex   int       // This party's index
    PartyID      []byte    // Optional identifier
    Rand         io.Reader // Defaults to crypto/rand
}

type DealerConfig struct {
    Threshold    int
    TotalParties int
    Rand         io.Reader
}

Both configs validate that 1 <= Threshold < TotalParties and TotalParties >= 2.

Go Interfaces