A Secure and Efficient Multi-authority Proactive Election Scheme

Abstract

In this paper we present a new secret-ballot multi-authority election scheme that is proactive and guarantees privacy, universal verifiability and robustness. In our scheme, a voter posts a single encrypted message as the ballot, accompanied by a non-interactive proof that it contains a valid vote. Our scheme is an efficient modification of the result by [CGS97]. The process of key recovery for decryption of votes in our scheme requires only O(r) steps, where r is the number of authorities required to decrypt the key, and the number of messages required for initial setup of the scheme is O(n), where n is the total number of authorities. The time complexity of key recovery in [CGS97] is O(r$\mbox{log}^2$r) and the complexity of number of messages is O($\mbox{n}^2$). Thus the proposed scheme is more efficient in terms of time complexity and number of messages required to be sent. We also outline a simple and elegant technique to make our scheme proactive. Our implementation results demonstrate the improved time complexity of the proposed scheme.