What's the use of a dongle? Where is it used?
It is an encryption product with the combination of software and hardware inserted into the computer parallel port. Generally, there are dozens or hundreds of bytes of nonvolatile storage space for reading and writing. Now the newer dog also includes a single chip microcomputer. Software developers can check whether the dongle is plugged 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 "package") with the tool attached to the dongle.
In short, it is the anti-theft version of software, protecting intellectual property rights, preventing software from being copied and illegally used. For example, the codemeter produced by WIBU in Germany is a hardware dongle.