Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!samsung!munnari.oz.au!uniwa!vax6!crobw
From: crobw@acad.cut.oz
Newsgroups: comp.misc
Subject: Re: Password algorithm
Message-ID: <2021.25e2c48a@acad.cut.oz>
Date: 21 Feb 90 08:40:41 GMT
References: <1019@philmtl.philips.ca> <1231@nixpbe.UUCP>
Organization: Curtin University of Technology
Lines: 22

In article <1231@nixpbe.UUCP>, mollers.pad@nixpbe.uucp (Moellers) writes:
>[...]
> There used to be an algorithm on the PDP-11 which packed 3 characters in
> 2 bytes. The characterset was restricted to UC and digits -> 36
> different chars, 
> 	max. value (35*36+35)*36+35 == 46655
> 

The method was called RADIX50, from 50 (base 8), or 40 (base 10), so that
another 4 special characters can be included. Specifically 6 characters from
the set of 40 can fit into 32 bits thus:-

((((C6*40+C5)*40+C4)*40+C3)*40+C2)*40+C1, where 0.le.Cj.le.39 (base 10)

40^6 = 4096*10^6 = F4240000 (hex)
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Rob Wright               |  psi%050529452300030::CROBW
Curtin University        |  CROBW%acad.curtin.edu.au@uunet.uu.net
Perth, Western Australia |  CROBW%acad.curtin.edu.au%munnari.oz@cunyvm.bitnet
Voice:+61 9 351 7385	 |  munnari!acad.curtin.edu.au!CROBW@uk.ac.ukc 
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