A Secure Event Agreement (SEA) protocol for peer-to-peer games

Abstract

Secure updates in a peer-to-peer game where all of the players are untrusted offers a unique challenge. We analyse the NEO protocol [5] which was designed to accomplish the exchange of update information among players in a fair and authenticated manner. We show that of the five forms of cheating it was designed to prevent, it prevents only three. We then propose an improved protocol which we call Secure Event Agreement (SEA) which prevents all five types of cheating as well as meeting some additional security criteria. We also show that the performance of SEA is at worst equal to NEO and in some cases better.

An Efficient and Secure Event Signature (EASES) Protocol for Peer-to-Peer Massively Multiplayer Online Games

“…NEO claims to prevent common protocol-level cheats with low latency, such that the adversaries cannot gain any advantages by modifying messages between players. Corman et al [14] later show that NEO cannot prevent all cheats as claimed, and present an improvement called Secure Event Agreement (SEA). However, both protocols are not practical due to the excessive use of cryptographic signatures.…”

“…Corman et al [14] present an improvement of NEO as described in Formula (2), where H() is a hash function, U r A is the update from player A for round r, n r is a random value for round r, SessID is the session ID to prevent replaying this message in a different session or with a different group of players, ID A is the unique identity of player A, and V h r−1 A is the update from player A for round r − 1 that includes a hash of the update.…”

“…an attacker can replay updates for another player, or send different updates to different opponents [14]) and present an improvement called SEA.…”

“…We briefly compare EASES against NEO [11] and SEA [14], both of which adopt traditional digital signatures. There are two signature operators in NEO and one signature operator in SEA.…”

“…As digital signature is necessary to achieve non-repudiation (i.e. undeniableness of user actions) due to its unforgeability and verifiability, some event update protocols [11,14] have been proposed to use digital signatures to sign every event messages to avoid cheating in P2P-based MMOGs. A player cannot repudiate his/her signature after signing a message under these two properties.…”