Semantic Integrity in Large-Scale Online Simulations

摘要

As large-scale online simulations such as Second Life and World of Warcraft are gaining economic significance, there is a growing incentive for attacks against such simulation software. We focus on attacks against the semantic integrity of the simulation. This class of attacks exploits the client-server architecture and is specific to online simulations which, for performance reasons, have to delegate the detailed rendering of the simulated world to the clients. Attacks against semantic integrity often compromise the physical laws of the simulated world - enabling the user's simulation persona to fly, walk through walls, or to run faster than anybody else. We introduce the Secure Semantic Integrity Protocol (SSIP), which enables the simulation provider to audit the client computations. Then we analyze the security and scalability of SSIP. First, we show that under standard cryptographic assumptions SSIP will detect semantic integrity attacks. Second, we analyze the network overhead, and determine the optimum tradeoff between cost of bandwidth and audit frequency for our protocol.