Software protection dongle

A software protection dongle (commonly known as a dongle or key) is an electronic copy protection and content protection device which, when attached to a computer or other electronic appliance, unlocks software functionality or decodes content. The hardware key is programmed with a product key or other cryptographic protection mechanism; it attaches via electrical connector to an external bus of the computer or appliance.

When used as a software protection device, dongles mostly appear as two-interface security tokens with transient data flow that does not interfere with other dongle functions and a pull communication that reads security data from the dongle. Without the dongle, the software may run only in a restricted mode, or not at all. When used as a device attached to a computer or TV or gaming console, dongles can enable functions that would not be present without it. For example, a dongle attached to a TV may receive an encoded video stream, decode it in the dongle, and then present this audio and video information to the TV.

In late 1970s/early 1980s, Wordcraft became the earliest program to use a software protection dongle. The dongle was passive using a 74LS165 8-bit shift register connected to one of the two tape cassette ports on the Commodore PET microcomputer. The tape cassette port supplied both power and bi-directional data I/O.

The requirements for security were identified by the author of the Wordcraft word processor, Pete Dowson, and his colleague Mike Lake. Through the network of PET users in the UK they made contact with Graham Heggie in Coventry and Graham's knowledge of electronics meant that they quickly arrived at the idea of a 74LS165 shift register connected to the tape cassette port which provided 5V power and lines to shift the bits into the software. The shift register contained only 8 bits but with lines tied to ground or 5V at random it could provide a random number between 0 and 255 which was sufficient security for the software. The prototype was on Veroboard which dangled from the tape port edge connector on wires - so "dangle" became "dongle". Pete Dowson wrote special self-modifying 6502 machine code to drive the port directly and to obfuscate the code when not in use.

The first device used a commercial potting box with black or blue epoxy resin. Wordcraft's distributor at the time, Dataview Ltd., then based in Colchester, UK, went on to produce dongles for other software developers. When Wordcraft International was formed in Derby, UK, responsibility for manufacture was transferred to Brian Edmundson who also produced the plastic moulding for the enclosure. One of the greatest regrets of Graham, Pete and Mike was that they did not patent the idea when they came up with it.

...
Wikipedia