In 2005, Chen et al. implemented a proxy raffle scheme for the Internet. Unfortunately, their scheme is unable to withstand Denial of Service (DoS) and impersonation attacks. We consequently propose a novel version of this scheme, in this paper, which can resist these malicious attacks. The security of our scheme is based on symmetric and asymmetric cryptosystems. A timestamp mechanism is also applied to prevent suffering the replay attack. Specifically, the communication load of our scheme is less than that of Chen et al.'s scheme. Thus, we can implement our method for the Internet as well as mobile devices.
