Dongle?

A dongle has encrypted key blocks that fit on the end, with a terminating block. Each dongle key has a required order.

For example, Xerox products often require three or four key blocks
in a prescribed order.

NB: it's completely illegal.

And when Xerox or whoever nabs you, well, good luck. The companies that do this tend to have high paranoia levels. They will come after your company for the return of the dongle if you don't pay annual support, for example.

I played with dongle that came with my Xerox printer software to see what they did; I was never able to duplicate everything.

The software cost US$18,000 to purchase, was third rate 16 bit code ported over to 32 bit. The annual 'support' fee was $3500.
Needless to say, my company eventually punted on the software -we developed our own.