What makes the SIM and USIM special?
In addition to being an important part of the network, the U/SIM is tied to the subscriber – unlike any device or handset. Since the operator controls the U/SIM, they own the identification of the end-user and have a billing relationship and superior access to other information such as customer location, etc. The identification of the end-user can be used for many applications, such as payments, VPN logins, digital identity, etc.
