SIM card: It is a physical card and needs to be installed by users themselves.

Sim card

I. Introduction:

SIM card is (subscriber identity module? Customer identification module), also known as user identification card, Smart cards and GSM digital mobile phones can only use this card. The information of digital mobile phone customers, encryption keys and user's phone book are all stored on the computer chip, which can be used for? GSM network? Identify customers and encrypt voice messages when customers call.

Second, the role:

1. stores user-related data, including fixed storage data (IMSI, authentication key KI, etc.). ); Network related data (location area identification code LAI, mobile subscriber temporary identification code TMSI, no access to public telephone network code, etc.). ); Related business codes (PIN, PUK, billing rate, etc. ); Phone book and other user information.

2. User PIN code (SIM card password) operation and management.

3, user identity authentication, to confirm whether the user identity is legal, the authentication process is between the network and the SIM card.

4. Security algorithm and key in SIM card (the most sensitive data in SIM card are security algorithm A3, A8, key Ki, PIN, PUK and Kc. The A3 and A8 algorithms were written during the production of SIM cards and cannot be read. The PIN code can be set by the user on the mobile phone, the PUK code is held by the operator, and Kc is derived from Ki in the encryption process).