The two-dimensional code access control is a new product that has emerged in the past few years, and has been well developed and popularized in the last one or two years. Compared with the traditional access control, the two-dimensional code access control mainly increases the opening method of the two-dimensional code verification, and enhances the security. For the working principle of two-dimensional code access control, but not many people understand, this article will come with everyone to understand, the working principle of two-dimensional code access control.
Read QR code
When the user scans the QR code, the QR code reader will read the relevant information of the QR code, and will use the hardware decoding method to interpret the QR code into a string type value. The interpreted value is Encrypted. After the data is interpreted, it will be transmitted to the access controller via Wiegand or RS232 or RS485 protocol.
Access controller decrypts data
After the data is transmitted to the access controller, since the data is still encrypted, the first step of the access controller is to decrypt the data. The decrypted data includes the user ID, area ID, QR code effective date, and customer self. Define the field. If the received data cannot be decrypted by the secret key, it is proved that the QR code is not generated by using the relevant program, and is an illegal two-dimensional code, so that the result is directly returned to the two-dimensional code card reader, and the card reader passes the indication. The lamp and the buzzer inform that it is an illegal card.
Online judgment and offline judgment
After the access controller decrypts the data, there will be two cases due to the setting. If the online judgment is set, the access controller will send the data to the access control server, and let the access controller determine whether the data is legal. If the offline judgment is set, the access controller will directly use the data in the built-in space to judge whether the data is legal.
process result
In the online judgment, the data is transmitted to the access control server, and the access control server will judge whether the data has the permission of the passage. After the judgment is completed, the result will be returned to the access controller, and the permission will open the access control and return the result to the two-dimensional code reading card. The two-dimensional code reader informs the legal card through the indicator light and the buzzer. If there is no permission, the access control is not opened, and the result is returned to the card reader, and the card reader informs the illegal card through the indicator light and the buzzer. The same is true for offline judgment. However, if the data is judged to be legal or illegal, it is handled by the access controller, and the processing result is the same as the online judgment.
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