Securing USIM-based Mobile Communications from Interoperation of SIM-based Communications

Mobile networks security is constantly evolving and adapting to meet the needs of users and network operators. It is a requirement that there be interoperation of legacy security frameworks into modern mobile networks. Mobile networks originally had no real security which proved to be a deployment that was attacked constantly and the providers were defrauded of millions of dollars. To address the issues the SIM authentication protocols were developed to secure the resources of the network providers. The original SIM security framework developed in GSM networks had weaknesses brought about by the one way authentication protocol as well as weaknesses in the algorithms used to secure the communication. The evolution of authentication in mobile networks to address the problems in the SIM framework brought about the creation of the USIM protocols used in UMTS, LTE and WiMAX to secure the network from the SIM framework security issues. The integration of those two SIM and USIM frameworks brought forward the major weaknesses first found in the SIM framework. This paper proposes simple and effective solutions to reduce the possible attacks on the USIM protocols due to the above integration. First we propose a subtle modification to the SIM based GSM security protocols as a stand-alone solution, and then a modification to the USIM based UMTS security protocols is proposed as a second solution.