A dongle or hardware key is a security module or key for unlocking a software program or for copy protection. A dongle is plugged into the parallel port of a personal computer( PC) as an intermediate connector and includes encryption electronics through which the data stream passes.
When the program is started or during program operation, the program checks for the presence of the dongle. The copy-protected software only works if the correct dongle is plugged in. Due to the high unit cost, dongles are typically used to authenticate proprietary applications such as business-to-business( B2B) or business-to-government( B2G).
In addition to the hardware-based dongle solution, there are software dongles. These are codes that are assigned by the manufacturer of the software and without which the program cannot be installed.
The technology of the dongles has developed further and is operated in USB interfaces as USB stick or on the interfaces of memory cards. There are also dongles that are built into components as microchips.