Performance Analysis of Security in GSM Networks

Abstract

This thesis is about analysis of a passive GSM monitoring system for 2.SG, 3G and 4G networks, of different mobile operators, that intercepts Voice and SMS communication and protocol information. The system will analyze and decipher the communication sessions and service information in a cellular GSM network. The system will be capable of passive deciphering of AS/I encryption. AS/I is a stream cipher and used in most of European countries to ensure privacy of the conversation in GSM mobile phone. To achieve the target I used the daughter boards of Universal Software Radio Peripheral (USRP) and airprobe (for air-interface analysis) and other tools available. The RF front end being used for signal acquisition is USRP-2920. GSM frames are captured using the USRP2 on a specific downlink frequency in linux. The data is then digitized and the digital data is sent for bit stream extraction. Airprobe is used for data analysis of bit stream. The gsm-receiver application is used to read the captured data file and the unencrypted messages are sent to Wireshark for data analysis. All the results extracted from the decryption of different networks show that the performance of presented sytem varies with the parameters of particular network. After deep analysis of the results it is figured out that the performance of the system and time it takes to capture, acquiring of Kc and decoding of the message is greater in Ufone. While Mobilink and Warid takes lesser time and Telenor takes even less time to be cracked. This work can further be enhanced for the performance analysis of the next generations.