\select@language {english} \addvspace {10\p@ } \addvspace {10\p@ } \contentsline {figure}{\numberline {2.1}{\ignorespaces Growth of mobile GSM subscriptions. Compiled from \cite {GSM2009,GSM_history2011,GSM_stats2011}}}{4} \contentsline {figure}{\numberline {2.2}{\ignorespaces The 3GPP Logo}}{5} \contentsline {figure}{\numberline {2.3}{\ignorespaces The main components of a GSM network.}}{6} \contentsline {figure}{\numberline {2.4}{\ignorespaces Evolution of mobile phones over the last decades.}}{7} \contentsline {figure}{\numberline {2.5}{\ignorespaces Structure of the IMSI.}}{8} \contentsline {figure}{\numberline {2.6}{\ignorespaces Authentication procedure}}{12}