BAHS: A Blockchain-Aided Hash-Based Signature Scheme

Hash-based one-time signatures are becoming increasingly important as they are post-quantum safe and have been used in multicast communication and other applications. However, managing the state of such signatures can present a significant challenge, as signers are typically responsible for ensuring that the state cannot be reused. Recently, blockchain, as a public platform, is used to design revocation management and status verification systems. While blockchain revocation is attractive, many well-known blockchains make use of ECDSA as their underlying signature scheme, and this is not post-quantum safe. Researchers have been working on replacing ECDSA with post-quantum signature schemes but they are much more costly. In this paper, we introduce a new one-time signature scheme, called Blockchain-Aided Hashbased Signature (BAHS), in which a hash-based commitment scheme acts as the building block, and signers' commitments and opened commitments are publicly accessible via a distributed blockchain. A signature is formed from the commitment/opened commitment and blockchain. Unlike existing blockchain systems, the commitment in BAHS is simpler than that in most existing hash-based one-time signature schemes or other post-quantum signature schemes. We provide a formal security model for the BAHS scheme and give the security proof. Finally, we have implemented our BAHS scheme and the result shows its practicality.