The UICC (Universal Integrated Circuit Card) is a smart card which was designed to be used as a container for the subscriber identification module (SIM) included in mobile phones, tablets, or other mobile devices. The decisive change compared to the previous traditional SIM cards is that multiple applications (SIM, USIM, ISIM, CSIM, etc.) can be stored on a single UICC. Mobile network operators use subscriber identification modules to store the credentials and encryption keys required for the authentication process.