A game theoretic defending model with puzzle controller for distributed dos attack prevention

Distributed denial-of-service is hard to prevent because the attackers could use the authentic IP addresses of the zombies to hide the source of attacks and to increase the computational ability. In this paper, a game theoretic defending model with puzzle controller against this kind of attack is proposed. The malicious attackers can be distinguished from legitimate clients by consuming their computational ability dramatically with the puzzle controller. The proper puzzle difficulty to filter out attackers is also deduced to give an instruction for clients and servers. Meanwhile, the relationships between certain variables are further investigated.