Article View: sci.crypt
Article #513Re: Crypt should be based on MD5 (was: the Crypt 16 discussion)
From: Dave Hayes
Date: Mon, 27 Jul 1992 17:21
Date: Mon, 27 Jul 1992 17:21
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dhesi@cirrus.com (Rahul Dhesi) writes:
>Suppose T1 is the time it takes for the intruder to determine a password
>by some sort of search (guessing, exchaustive, whatever).
>So what are useful values for T1 and T2?
There are other factors that put different values in T1.
If the intruder is local and physically present...he or she may
snoop over your shoulder for the password. Assuming a login once per
day, the average value of T1 could be on the order of a month.
>CONCLUSION 1: If passwords are well-chosen, password expiration adds
>nothing to security. If passwords are poorly-chosen, password expiration
>must occur too rapidly to be of much use.
Therefore Conclusion 1 is only valid for the case where the intruder's
only access is a passwd file.
--
Dave Hayes - Network & Communications Engineering - JPL / NASA - Pasadena CA
dave@elxr.jpl.nasa.gov dave@jato.jpl.nasa.gov ...usc!elroy!dxh
If you regret your gift - take it back.
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Path: arc1-ca.pugleaf.net!sparky!uunet!darwin.sura.net!mips!swrinde!elroy.jpl.nasa.gov!jato!dave From: dave@jato.jpl.nasa.gov (Dave Hayes) Newsgroups: sci.crypt,comp.security.misc Subject: Re: Crypt should be based on MD5 (was: the Crypt 16 discussion) Message-ID: <1992Jul27.172118.13874@jato.jpl.nasa.gov> Date: 27 Jul 92 17:21:18 GMT References: <2a510a22@babyoil.ftp.com> <709960260@romeo.cs.duke.edu> <62451@cup.portal.com> <16990@ulysses.att.com> <1992Jul23.013037.24195@cirrus.com> Reply-To: dave@jato.jpl.nasa.gov Organization: Jet Propulsion Lab - Pasadena, CA Lines: 23