Article View: sci.crypt
Article #4288Re: Yet Another useful paper
From: David L. Jobusch
Date: Tue, 03 Jan 1989 16:12
Date: Tue, 03 Jan 1989 16:12
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2059 bytes
In article <1273@altger.UUCP> vyrus@altger.UUCP (vyrus) writes: >I have heard about a paper presenting a mathematical formulation of a fast >implementation of the DES in software able of speding up UNIX crypt() >password encryption routine by roughtly 20 times. (@ulysses.homer.nj.att.com) > >I wonder if someone would mind telling more about the matter or, (even better!) >sending me an high language (C? great!) implementation of such algorithm. > >Thanks in advance. > >=David= Well, I suspect one way you might be able to "speed up" UNIX crypt() is to remove the following two lines from the code in 4.3BSD crpyt.c/crypt(): for(i=0; i<25; i++) encrypt(block,0); Looking at the code, each 64-bit block is encrypted 25 times. ( encrypt() takes "block", encrypts it, and returns it in "block".) Besides the intention of making crypt slow in the first place, does anyone have comments on the usefullness of multiple encryption of blocks? I have heard some arguments that doubt multiple encryption increases protection against the bad guy. Also, I have what seems to be a very quick implementation of DES written in 'C' that was posted to UseNet some time ago. Interested individuals can contact me email at: Dave Jobusch Iowa State University Telecommunications Ames, IA jobusch@atanasoff.cs.iastate.edu
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!sharkey!atanasoff!jobusch From: jobusch@atanasoff.cs.iastate.edu (David L. Jobusch) Newsgroups: sci.crypt,comp.unix.wizards Subject: Re: Yet Another useful paper Summary: Why da heck is crypt() so sloooow? Keywords: crypt(),DES,YAUP Message-ID: <581@atanasoff.cs.iastate.edu> Date: 3 Jan 89 16:12:32 GMT References: <11013@ulysses.homer.nj.att.com> <2308@cuuxb.ATT.COM> <4420@xenna.Encore.COM> <2743@epimass.EPI.COM> <110@microsoft.UUCP> <1273@altger.UUCP> Reply-To: jobusch@atanasoff.cs.iastate.edu (David L. Jobusch) Followup-To: sci.crypt Organization: Iowa State U. Computer Science Department, Ames, IA Lines: 34