Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!rutgers!mit-eddie!cybvax0!frog!john From: john@frog.UUCP (John Woods, Software) Newsgroups: sci.crypt Subject: Re: VC2000 "Update" Message-ID: <1207@frog.UUCP> Date: Tue, 23-Dec-86 21:42:00 EST Article-I.D.: frog.1207 Posted: Tue Dec 23 21:42:00 1986 Date-Received: Wed, 24-Dec-86 06:45:46 EST References: <3806@utcsri.UUCP> Organization: Superfrog Heaven [ CRDS, Framingham MA ] Lines: 37 Two comments on all this: > From the January 1987 issue of >Home Satellite TV<, "A "CHIP" That Unlocks > Scrambling" by Bob Cooper, Jr. (pp. 51-55, 67): > "The Videocipher has been broken through the U30 device > found inside of the M/A Com descrambler and pictured on > our front cover. It holds the key to a "quick decoding" > fix discovered by many Videocipher hackers. The chip is > re-programmed with user instructions which essentially > unlock the descrambler for transmissions which were > previously secure." > >The basic question still remains: Did they break DES or short-cut the keying? I am told that they keys are transmitted encrypted with keys that are shorter than 56 bits (i.e., some of the bits are constant), such that cracking by exhaustive search is practical. > the author doesn't know encryption or the law very well. At one point he > quotes an otherwise unreferenced announcement by NSA: > "Effective 1 January 1986 ... the U.S. government will no longer > sanction the DES code for encryption systems. The DES code has > become vulnerable to code breakers." > Uhh, somehow I don't think that's quite their style... > That doesn't sound like the NSA either, but I know they've said the beaurocratic equivalent. Some time ago, Shamir (I think) demonstrated that DES was untrustworthy by concocting a similar encryption scheme, showing it to people who examined it and decided that it was as secure as DES itself -- then he showed them the trapdoor hidden in the tables. Thus, the belief that DES _can_ have no trapdoor is undermined. -- John Woods, Charles River Data Systems, Framingham MA, (617) 626-1101 ...!decvax!frog!john, ...!mit-eddie!jfw, jfw%mit-ccc@MIT-XX.ARPA Ceci nes pas un .signature. -- Not Quite Magritte