Skip to Main Content
To overcome the congenital defects of the UMTS's Authentication and Key Agreement (AKA) protocol standard, Ou et al. proposed an improved protocol called the cocktail-AKA protocol recently. In this paper, we first show that it has some security weaknesses, which can be exploited by an adversary to mount a denial of service attack and an impersonation attack. Finally, an effective countermeasure is suggested.