Analysis and countermeasure on vulnerability of WPA key exchange mechanism

In this paper, we analyze some weaknesses in WPA authenticator key management state machine and propose the countermeasures to overcome these problems. Our researches on IEEE 802.11i authenticator state machine that is WPA authenticator key management state machine reveal that the state machine cannot support the stable group key setting and is vulnerable to the replay attack and DoS attack. We describe 3 problems related to these vulnerabilities, propose the respective solutions and reconstruct WPA authenticator key management state machine to which the alternative solutions are applied.