jgd@Dixie.Com (John G. DeArmond) (01/10/91)
shiva@pro-smof.cts.com (System Smof) writes: >>Although the people in sci.crypt probably have a better handle on it >>than he did, Bamford claims that the NSA convinced IBM to shorten the >>key from 128 bits to 56. Apparently in exchanged the NSA helped IBM >>strengthen the S-box structures before DES was released as a standard. >>Also, this was brought up in Senate Intelligence Committee hearings in >>1977. >That the crux of what I had heard (about the unreliability of the DES). God, we beat this one to death. One could just as easily hypothesize that the NSA proved to IBM that a 56 bit key is as functionally secure as a 128 bit key but at a tremendous computational saving. In the absence of evidence pointing either way, one hypothesis is as good as the conspiracy theory. The rumor of DES's insecurity propagates despite the fact that there has been not one substantiated rumor to my knowledge of anyone breaking the algorithm or discovering a trap door. It is simply incredible that if the NSA had broken DES, that someone would not have leaked something sometime. If they really have kept the lid on a DES trapdoor, it would be the ONLY secret the government has managed to keep since D-day. Which of course, has nothing to do with the use of DES or other algorithm as an aid to the commission of a crime. The government has more than adequate ways of getting a password out of you if that is all that is impeding their investigation. -- John De Armond, WD4OQC | "Purveyors of speed to the Trade" (tm) Rapid Deployment System, Inc. | Home of the Nidgets (tm) Marietta, Ga | "To be engaged in opposing wrong offers but {emory,uunet}!rsiatl!jgd | a slender guarantee of being right."
greg@ogre.cica.indiana.edu (Gregory TRAVIS) (01/10/91)
In <5729@rsiatl.Dixie.Com> jgd@Dixie.Com (John G. DeArmond) writes: >shiva@pro-smof.cts.com (System Smof) writes: >>>Although the people in sci.crypt probably have a better handle on it >>>than he did, Bamford claims that the NSA convinced IBM to shorten the >>>key from 128 bits to 56. Apparently in exchanged the NSA helped IBM >>>strengthen the S-box structures before DES was released as a standard. >>>Also, this was brought up in Senate Intelligence Committee hearings in >>>1977. >>That the crux of what I had heard (about the unreliability of the DES). >God, we beat this one to death. One could just as easily hypothesize >that the NSA proved to IBM that a 56 bit key is as functionally secure >as a 128 bit key but at a tremendous computational saving. In the >absence of evidence pointing either way, one hypothesis is as good >as the conspiracy theory. I apologize if this point has been hashed over, as I've not seen the previous discussions about DES and the NSA. But, I thought the whole point WAS indeed that the 56-bit key offered "tremendous computational savings" over the 128-bit key. The NSA may have concluded that using brute-force methodes to break the DES would be impossible for the 128-bit codes (given existing and projected advances in computational hardware). Bamford's _Puzzle Palace_ suggests that the NSA felt that it could break DES by brute force in a reasonable amount of time on its own hardware if a 56-bit key were the standard. And the supposition is, of course, that the NSA will always have access to bigger and better hardware than the average Joe. Bamford gives several other examples where the NSA has acted very aggressively when it comes to maintaining a monopoly of coding systems, so this type of behavior on their part is not unknown or unusual. What IS left unexplained is why the NSA would believe that anyone seriously interested in escaping detection would nonetheless implement DES as defined by the standard! -- Gregory R. Travis Indiana University, Bloomington IN 47405 greg@cica.cica.indiana.edu Center for Innovative Computer Applications Disclaimer: Everything I say is true and I never lie.