In this paper we present a fully functional RSA/DSA-based e-voting protocol for online elections that corrects and improves a scheme previously proposed by Lin-Hwang-Chang [I. Lin, M. Hwang, C. Chang, Security enhancement for anonymous secure e-voting over a network, Comput. Stand. Interfaces 25 (2) (2003) 131-139.]. We found that Lin-Hwang-Chang's scheme and a recent modification of it by Hwang-Wen-Hwang [S. Hwang, H. Wen, T. Hwang, On the security enhancement for anonymous secure e-voting over computer network, Comput. Stand. Interfaces 27 (2) (2005) 163-168.] have an important weakness. Moreover, the scheme proposed by Yang-Lin-Yang [C. Yang, C. Lin, H. Yang, Improved anonymous secure e-voting over a network, Information and Security 15 (2) (2004) 185-191.] also suffers from this same problem. We describe in detail our findings and propose a new scheme to overcome the weakness we found in these schemes effectively. Finally, we describe the implementation details of our protocol and present its preliminary performance evaluation.

Abstract-Recent advances in communication networks and cryptographic techniques have made possible to consider online voting systems as a feasible alternative to conventional elections. Until today several protocols for electronic voting have been proposed, unfortunately only a few of them have been implemented in an end-to-end fully functional system. In this paper we present a secure electronic voting system for medium scale on-line elections (SELES). Our system efficiently implements a security communication protocol offering protection against double voting and others frauds while avoiding any private voting channel. SELES accomplishes all the standard properties of conventional voting systems, namely, accuracy, democracy, privacy, verifiability, simplicity, flexibility and double voting detection. Our system has been tested in a distributed and heterogeneous Internet network comprised by workstations, laptops and PDA nodes interacting through wired and wireless connections. Additionally, SELES has been designed to deal with communication failures, thus achieving a certain degree of robustness.