SIM CARD .... DO you ever try to know about this?

               Subscriber identity module

SIM CARD

A subscriber identity module or subscriber identification module (SIM) is an integrated circuit that securely stores the international mobile subscriber identity (IMSI) and the related key used to identify and authenticate subscribers on mobile telephonydevices (such as mobile phones and computers).

A SIM circuit is embedded into a removable plastic card. This plastic card is called a "SIM card" and can be transferred between different mobile devices. A SIM card follows certain smart cardstandards. SIM cards were first made the same size as a credit card (85.60 mm × 53.98 mm × 0.76 mm). The development of physically smaller mobile devices prompted the development of smaller SIM cards where the quantity of card surrounding the integrated circuit is reduced.

A SIM card contains its unique serial number (ICCID), international mobile subscriber identity (IMSI), security authentication and ciphering information, temporary information related to the local network, a list of the services the user has access to and two passwords: a personal identification number (PIN) for ordinary use and a personal unblocking code(PUK) for PIN unlocking.

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