Section: 5.3.1 User-to-USIM authentication
Content: This feature provides the property that access to the USIM is restricted until the USIM has authenticated the user. Thereby, it is ensured that access to the USIM can be restricted to an authorised user or to a number of authorised users. To accomplish this feature, user and USIM must share a secret (e.g. a PIN) that is stored securely in the USIM. The user gets access to the USIM only if he/she proves knowledge of the secret. This security feature is implemented by means of the mechanism described in TS 31.101[ UICC-terminal interface; Physical and logical characteristics ]  [5].