How do the television program codes for VCR Plus work? VCR Plus is a handheld device similar to a TV remote control that tells the VCR to record a target program at a specific time, channel, and duration based on a numeric code listed in TV Guide and many newspapers. I see no pattern to these codes, which have a different meaning each month. One month “12345” may indicate a Friday night news show on Channel 2, the next month something entirely different. How can this be? There must be some sort of algorithm. Any ideas? –Frederick C. Lee, Honolulu, Hawaii
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Yes, there is an algorithm. If we had any sense we would leave it at that. But no, I can see you want to know what the algorithm is. Maybe you’d also like to know how to perform brain surgery with a can opener. Either way we are stretching the limit of what human ingenuity can accomplish in a 600-word column. But hey, your wish is my command.
But Gemstar didn’t reckon with the nation’s tireless computer geniuses. Three of them, Ken Shirriff, Curt Welch, and Andrew Kinsman, got together via the Internet computer network, broke the code (most of it, anyway), and published the result in the journal Cryptologia last July. Somebody else used this as the basis for a VCR Plus encoding/decoding program that is now posted on computer bulletin boards and such (e.g., CompuServe, Zenith forum, VCRPLS.ZIP). You want to decrypt VCR Plus codes the E-Z way, get the program. For the silicon-adverse, however, here’s an example of how the algorithm works, taken from the Cryptologia article:
