Minimization of Latency in Cheat-Proof Real-Time Gaming by Trusting Time-Stamp Servers

Communication latency with the lockstep protocol is minimized under the assumptions that (1) time-stamp servers are available near each player that issue serially numbered time stamps and that (2) there is no communication break down between the player and the time-stamp server. Those assumptions are relatively moderate since the time-stamping service is becoming the fundamental infrastructure of the cyberworlds. Each player sends its own action to the other player and also sends its hash to the nearest time-stamp server. The time-stamp server sends back to the player the signed hash with time and a serial number involved. The signature is an undeniable evidence of the action. The actions are checked if they are compatible with the hashes and the signed hashes are checked if they have the correct time and the serial numbers are contiguous. This verification can be done as a batch after the game is finished. While the original lockstep protocol suffers from the latency as much as the round-trip time of packets and the other existing improved protocols alleviate the latency at the cost of lower security, the proposed protocol has the latency as little as the packet travelling time from one player to another and has the same security as the original under the assumption that we trust the time-stamp servers.