What is the principle of dongle? How to achieve communication?

What is the principle of dongle? How to achieve communication?

Principle of dongle: the dongle realizes encryption by exchanging data with the dongle during software execution. The built-in single chip microcomputer circuit (also known as CPU) of the dongle makes the dongle have the processing ability of judgment and analysis, and enhances the active anti decryption ability. This encryption product is called "intelligent" dongle. The built-in MCU of the dongle contains algorithm software dedicated to encryption. After the software is written into the MCU, it can no longer be read out. This ensures that the dongle hardware cannot be copied. At the same time, the encryption algorithm is unpredictable and irreversible.

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Dongle is a software encryption product with a combination of software and hardware inserted into the computer parallel port, which is adopted by most software developers. plus

The secret dog generally has dozens or hundreds of bytes of nonvolatile storage space for reading and writing. The newer secret dog also contains a single chip microcomputer. Software developers can check whether the dongle is inserted into the parallel port through data exchange between the interface function and the dongle (i.e. reading and writing the dongle); Or directly encrypt your own EXE file (commonly known as "shell") with the tool attached to the dongle. In this way, software developers can set multiple software locks in the software and use the dongle as the key to open these locks; If the dongle is not inserted or does not correspond to the dongle, the software will not execute normally.