Supported Schemes

Scheme Registry

Each scheme registers itself via init() and is identified by a SchemeID constant.

const (
    SchemeFROST    SchemeID = 1  // Schnorr threshold (Ed25519)
    SchemeCMP      SchemeID = 2  // CGGMP21 threshold ECDSA
    SchemeBLS      SchemeID = 3  // BLS threshold (non-interactive)
    SchemeRingtail SchemeID = 4  // Lattice-based (post-quantum)
)

Comparison

Property	CGGMP21	FROST	BLS	Ringtail
Signature type	ECDSA	Schnorr	BLS12-381	Lattice
Post-quantum	No	No	No	Yes
Signing rounds	Multi	2	1 (non-interactive)	2
DKG rounds	Multi	2	2	Trusted dealer
Aggregatable	No	No	Yes	No
Chain compatibility	Bitcoin, Ethereum	Solana, Sui	Lux consensus	All (PQ bundles)
Implementation	`mpc/pkg/threshold`	`mpc/pkg/threshold`	`crypto/threshold/bls`	`ringtail/threshold`

Threshold ECDSA signing based on the Canetti-Gennaro-Goldfeder-Makriyannis-Peled protocol. Produces standard ECDSA signatures compatible with Bitcoin and Ethereum. Implemented in the mpc repository.

FROST (SchemeFROST)

Flexible Round-Optimized Schnorr Threshold signatures. 2-round protocol producing Schnorr signatures compatible with Ed25519/EdDSA. Implemented in the mpc repository.

BLS (SchemeBLS)

BLS12-381 threshold signatures with non-interactive aggregation. Shares can be combined without additional communication rounds. Built into crypto/threshold/bls. Used for Lux consensus block signing.

Ringtail (SchemeRingtail)

Lattice-based threshold signatures using Module-LWE. The only post-quantum scheme. 2-round signing protocol with trusted dealer key generation. Implemented natively in the ringtail repository.

Selecting a Scheme

func schemeForChain(chain string) (threshold.Scheme, error) {
    switch chain {
    case "ethereum", "bitcoin":
        return threshold.GetScheme(threshold.SchemeCMP)
    case "solana", "sui":
        return threshold.GetScheme(threshold.SchemeFROST)
    case "lux":
        return threshold.GetScheme(threshold.SchemeBLS)
    default:
        return nil, fmt.Errorf("unsupported chain: %s", chain)
    }
}

Ringtail is used alongside BLS in Lux Quasar consensus for post-quantum security bundles, not as a standalone chain signing scheme.