Paper 2021/417

History Binding Signature

Shlomi Dolev and Matan Liber

Abstract

Digital signatures are used to verify the authenticity of digital messages, that is, to know with a high level of certainty, that a digital message was created by a known sender and was not altered in any way. This is usually achieved by using asymmetric cryptography, where a secret key is used by the signer, and the corresponding public key is used by those who wish to verify the signed data. In many use-cases, such as blockchain, the history and order of the signed data, thus the signatures themselves, are important. In blockchains specifically, the threat is forks, where one can double-spend its crypto-currency if one succeeds to publish two valid transactions on two different branches of the chain. We introduce a single private/public key pair signature scheme using verifiable random function, that binds a signer to its signature history. The scheme enforces a single ordered signatures' history using a deterministic verifiable chain of signature functions that also reveals the secret key in case of misbehaviors.