An efficient and secure event signature (EASES) protocol for peer-to-peer massively multiplayer online games

In recent years, massively multiplayer online games (MMOGs) have become very popular by providing more entertainment and sociability than single-player games. In order to prevent cheaters to gain unfair advantages in peer-to-peer (P2P)-based MMOGs, several cheat-proof schemes have been proposed by using digital signatures. However, digital signatures generally require a large amount of computations and thus may not be practical for interactive real-time applications such as games. Based on the concept of one-time signature, we propose an efficient and secure event signature (EASES) protocol to efficiently sign discrete event messages with hash-chain keys. As most messages need only two hash operations to achieve non-repudiation and event commitment, usage of digital signatures is greatly reduced. We also describe a dynamic version of EASES that does not require the pre-production of hash-chain keys to reduce key preparation time and memory usage at the expense of a slight delay of message commitment. As shown by both analysis and experiments, the computation, memory, and bandwidth footprints of EASES are low, making it readily applicable to P2P-based MMOGs.