Symmetric key based 5G AKA authentication protocol satisfying anonymity and unlinkability

The recently standardised 5G AKA protocol, to be used in the next generation of mobile communications, possesses some severe shortcomings. In particular, different types of attacks, leaking parts of the identity, activity pattern and localisation of the user, have been proposed in literature. In this paper, we propose a new version of the 5G AKA protocol, capable of offering resistance to all the known attacks and providing the required security features like anonymity, unlinkability, mutual authentication and confidentiality. The proposed protocol is completely symmetric key based and relies on cryptographic primitives currently available in the hardware of the universal subscriber identity module (USIM). Compared to the original protocol or other recently proposed versions, our protocol does not require the usage of public key encryption for hiding the real identity. Also the number of communication phases in the protocol is optimised and limited to two. The security of the protocol has been demonstrated using RUBIN logic.