Article View: sci.crypt
Article #1272Re: VCR Plus Codes
From: Peter Trei
Date: Wed, 14 Oct 1992 15:22
Date: Wed, 14 Oct 1992 15:22
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In article <1992Oct12.224852.2170@draco.macsch.com> m_reymond@macsch.com
writes:
>I am new to this newsgroup and I have been trying to figure out how
>the VCR Plus codes are derived?
>Thanx
Gemstar claims all kinds of patents and copyrights on the code
numbers and the software to create them, and has threatened lawsuits
against people who experimented with them, including people on this
newsgroup.
Nevertheless, the algorithm for codes of up to 6 characters (ie,
the vast majority of them) has been decrypted and published:
"Decoding a VCR controller code" by Shirriff, Welch, and Kinsman, in
Cryptologia, Vol XVI, number 3 (July 1992), p227-234.
Includes a detailed description of the process, and example
pseudocode.
Curiously, the channel number is only 5 bits long. Is this device
useful on large cable systems?
Peter Trei
ptrei@Mitre.org
Technical Details
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Newsgroups: sci.crypt Path: arc1-ca.pugleaf.net!sparky!uunet!charon.amdahl.com!pacbell.com!ames!agate!linus!linus.mitre.org!bistromath!ptrei From: ptrei@bistromath.mitre.org (Peter Trei) Subject: Re: VCR Plus Codes Message-ID: <1992Oct14.152230.16549@linus.mitre.org> Sender: news@linus.mitre.org (News Service) Nntp-Posting-Host: bistromath.mitre.org Organization: The MITRE Corporation References: <1992Oct12.154619.17062@draco.macsch.com> <1992Oct12.224852.2170@draco.macsch.com> Date: Wed, 14 Oct 1992 15:22:30 GMT Lines: 27