New Construction of Blind Signatures from Braid Groups

A new construction of a blind signature scheme based on braid groups is proposed. In the random oracle model, the proposed scheme is provably unforgeable against chosen message attacks, assuming that the one-more matching conjugate problem in braid groups is intractable. Furthermore, in the infinite group model, the scheme is proved to be perfectly blind. Our construction represents a technique to lift a braid group to its conjugate subgroups for particular applications. The proposed scheme is very fast in signing but relatively slow in verifying and is thus suitable for scenarios that require signing as soon as possible but permit a slight delay in verifying. In addition, our proposal is invulnerable to known quantum attacks and therefore would be a good alternative to RSA-based and DLP-based blind signatures in the post-quantum era.