Privacy and Anonymity Protection with Blind Threshold Signatures

Abstract

A set of group-oriented blind (t, n) threshold signature schemes is proposed based on the discrete logarithm problem. Using these schemes, any t out of n signers in a group can represent the group in signing blind threshold signatures. A threshold signature in the proposed schemes is the same size as an individual signature, and the signature verification process is simplified by means of a group public key. The schemes are suitable for single-authority applications in privacy protection, secure voting systems, and anonymous payment systems for distributing the power of a single authority. The assistance of a mutually trusted authority is not required. In addition, individual signers can choose their own private keys, and all the members together decide on the group public key.