What does China Mobile mean by its own online business hall value-added service fee?

1. Self-owned value-added service fees are some additional services handled by operators except SIM cards.

2, in short, besides talking. SMS, MMS, CRBT, mobile banking, mobile securities, mobile email, information on demand, access to Internet GPRS traffic with mobile phones are all value-added services.

3. In order to further improve the service level of telephone charge information, China Mobile has standardized the telephone charge information, and listed such items as call forwarding, GSM, SMS, voice SMS, MMS, GPRS traffic, caller ID, mobile phone newspaper and color ring back tone as "value-added service fees".

Extended data

Main functions of SIM card:

First, store user-related data.

The data stored in the SIM card can be divided into four categories:

1, the first category is permanently stored data. This kind of data is written by SIM card center before ME (mobile equipment) is sold, including international mobile subscriber identification number (IMSI), authentication key (KI) and so on.

2. The second category is temporarily stored network data. Such as location area identification code (LAI), mobile subscriber temporary identification code (TMSI) and public telephone network code without access.

3. The third category is related business codes, such as personal identification number (PIN), unlocking code (PUK), billing rate, etc.

4. The fourth category is the phone book, which is the phone number entered by mobile phone users at any time.

Second, the operation and management of user PIN.

The SIM card itself is protected by a PIN code, which is a 4-to 8-digit personal password. Only when the user enters the correct PIN code can the SIM card be activated, the mobile terminal can access the SIM card, and the user can talk online after the PIN authentication is passed.

Third, user authentication.

1. Confirm whether the user's identity is legal. The authentication process is between the network and the SIM card, and the authentication time is generally when the mobile terminal registers for network access and calling.

2. At the beginning of authentication, the network generates a random number RAND with 128 bits and sends it to the mobile station through the wireless control channel. The SIM card calculates the received response signal SRES of RAND according to the key Ki in the card and the algorithm A3, and sends the result back to the network.

3. The network finds out the user's key Ki in the authentication center, calculates SRES with the same RAND and algorithm A3, and compares it with the received SRES. If they are consistent, the authentication is passed.

Fourthly, the security algorithm and key in SIM card.

The most sensitive data in SIM card are security algorithms A3, A8, keys 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.

Baidu encyclopedia: SIM card