|
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. ==History== 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 shift register connected to the tape cassette port. 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. 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. Versions of the Wordcraft dongle were later produced for Centronics parallel ports, 25 pin serial ports and 9 pin serial ports. Among the computers supported, before the arrival of the IBM PC, were Chuck Peddle's Sirius Systems Technology Victor 9000, the ACT Apricot Computers and the DEC Rainbow 100. An early example of the term was in 1984, when early production Sinclair QLs were shipped with part of the QL firmware held on an external 16 KB ROM cartridge (infamously known as the "kludge" or "dongle"), until the QL was redesigned to increase the internal ROM capacity from 32 to 48 KB. Dongles rapidly evolved into active devices that contained a serial transceiver (UART) and even a microprocessor to handle transactions with the host. Later versions adopted the USB interface in preference to the serial or parallel interface. The USB interface is gradually becoming dominant. A 1992 advertisement for Rainbow Technologies claimed the word dongle was derived from the name "Don Gall". Though untrue, this has given rise to an urban myth.〔See advertisement in Byte Magazine, August 1992, p. 133〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Software protection dongle」の詳細全文を読む スポンサード リンク
|