Abikoye, Oluwakemi ChristianaOluwade, Dele2018-03-212018-03-212008Abikoye, O.C. & Oluwade, Dele. (2008): Computational Analysis of GSM Security Algorithm. African Journal of Computing & ICT (IEEE Nigeria Computer Chapter). 1 (3); 27-33http://www.ajocict.net/uploads/V1N2P2_-_2008_-_AJOCICT_-COMPUTATIONAL_ANALYSIS_OF_GSM_SECURITY.pdfhttp://hdl.handle.net/123456789/157The security and authentication mechanisms incorporated in the Global System of Mobile Network (GSM) make it the most secure mobile communication standard currently available, particularly in comparison to the analog systems. GSM security and encryption algorithm are used to provide authentication and radio link privacy to users on GSM network. Security in GSM consists of the following aspects: subscriber identity authentication, subscriber identity confidentiality, signaling data confidentiality, and user data confidentiality. These various security aspects are addressed by the user authentication algorithm(called A3), the signal encryption algorithm(A5) and the encryption key generation algorithm(A8). Both A3 and A8 algorithms are similar in functionality and are commonly implemented as a single algorithm called COMP128. In this paper, a computational time complexity analysis of COMP 128 is performed. It is shown that the running time of user authentication algorithm COMP128 is constant, meaning that the number of executions of basic operations in COMP128 algorithm is fixed and so the total time is bounded by a constantenComputational complexityCOMP128GSMSecurityAlgorithmA3A8Article