Practical Zero-Trust Threshold Signatures in Large-Scale Dynamic Asynchronous Networks

Abstract

We present novel protocols for ECDSA and EdDSA/Schnorr signatures distributing the signing process between a client and a permissionless decentralized blockchain. This approach addresses the honeypot problem where custodians holding more assets face greater compromise risks.

Key contributions include:

• Implementation over asynchronous reliable broadcast channels with identifiable abort, public verifiability, and guaranteed output delivery
• Support for post-determined dynamic quorum in each communication round
• Network reconfiguration with complexity independent of client numbers
• Weighted threshold access structures with costs depending on individual weight
• Removal of zero-knowledge proofs toward the client
• Non-interactive presigns for clients

The protocol achieves UC-security for parallel client execution and introduces Slightly-Enhanced ECDSA Unforgeability for concrete security on 256-bit elliptic curves. Applications span cryptocurrency wallets, decentralized bridges, future transactions, and cross-chain interoperability.