Pay to find someone to do a similar function through the module microcontroller

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ThreeFat
 
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Pay to find someone to do a similar function through the module microcontroller

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Using the SIM card slot to realize the principle of virtual SIM card. 2.1; The working principle of mobile phone and SIM card booting
As we all know, every mobile phone has a SIM card, and the SIM card is a smart card that complies with the ISO 7816 international standard protocol. When the mobile phone is turned on, it will load voltage to the SIM card, and then send a reset pulse to the RESET pin of the SIM card. After the pulse is sent, the SIM card will return ATR information. According to the information of ATR, the basic information of the SIM card can be judged. Afterwards, a series of data exchanges between the SIM card, the mobile phone and the base station can be approved by the authentication center, allowing the user to use various agreed services.
2.2; The process of SIM card logging into the base station for authentication
    SIM card user identity authentication: To confirm whether the user identity is legal, the authentication process is carried out between the network and the SIM card, and the authentication time is generally when the mobile terminal registers to the network and calls. At the beginning of the authentication, the network generates a 128-bit random number RAND and transmits it to the mobile station through the radio control channel. The SIM card calculates the response signal SRES to the received RAND according to the key Ki in the card and the algorithm A3, and sends The result is sent back to the network side. And the network end finds out the key Ki of the user at the authentication center, uses the same RAND and algorithm A3 to calculate the SRES, and compares it with the received SRES, if they are consistent, the authentication passes.
               2.3; Authentication process of virtual SIM card
 Because the local SIM card is locally connected to the mobile phone, the mobile phone can directly read and write data to the IO port of the SIM card holder. To use the SIM card in the card pool, after the mobile phone is turned on, it is no longer possible to read information from the local SIM card holder, but to change the startup program so that after the phone is turned on or reset, it first communicates with the card pool (or with the server and then through the server and the card) Pool) to establish a data connection channel. The establishment of this channel is generally through a WiFi connection or similar to a dual-card mobile phone first activating one of the SIM cards for network connection. Then send a startup command to the SIM card you want to get ATR. The subsequent process is no different from the local SIM card operation, the only difference is that the delay may be slightly longer due to network communication, so the SIM card pool is placed in the fastest possible network environment. In addition, the card pool is transparently transmitted when forwarding commands, and does not decode the data in the process.
  Assume that a 2G module is used as the authentication channel for the terminal to communicate with the card pool server. The startup process is shown in Figure 1.
(1) Turn on the 2G module, establish a GPRS channel to communicate with the base station and connect to the Internet.
(2) An APP on the 2G module obtains the current location information to the card pool server and requests SIM information.
(3) After the card pool server obtains the location of the terminal, it finds the SIM card matching the local network in the card pool, reads the basic information of the SIM card and returns it to the APP of the 2G module.
(4) After the APP on the 2G module receives the basic information of the SIM card, it passes it to the protocol stack of the 4G module, and the 4G module initiates the registration information to the 4G base station.
(5) The 4G base station first sends the authentication information to the 4G module from the 4G module, and the 4G module transparently transmits the authentication request to the card pool authentication server through the 2G module.
(6) The card pool authentication server passes the authentication information to the selected SIM for authentication operation, and returns the result to the 4G module in the original way.
(7) The 4G module sends the result of the authentication operation to the base station, thus completing a network-based authentication process.
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ThreeFat
 
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Re: Pay to find someone to do a similar function through the module microcontroller

Post by ThreeFat »

Or the function of connecting the sim card and the terminal through the network as shown in the picture, and I only need one card slot. Please contact me.

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ThreeFat
 
Posts: 3
Joined: Mon Apr 10, 2023 12:49 am

Re: Pay to find someone to do a similar function through the module microcontroller

Post by ThreeFat »

Or the function of connecting the sim card and the terminal through the network as shown in the picture, and I only need one card slot. Please contact me.

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