A Proxy E-Raffle Protocol Based on Proxy Signatures

In 2009, Chang and Cheng proposed an efficient proxy raffle protocol. In their scheme, the raffle tickets are known by participants as well as raffle organizers. Hence, unless we implicitly add the unrealistic assumption that the organizer is trustworthy, this may cause problems and threaten the security of the e-raffle from the viewpoint of participants. In this paper, we use the concept of proxy signatures and symmetric cryptography to propose an efficient proxy raffle scheme which overcomes this weakness. We show that the proposed scheme achieves all other security requirements mentioned in the literature. The proposed scheme is shown to outperform the scheme of Chang and Cheng in terms of communication load and computational complexity.