Re: Password Security Policy Question

From: Nate Lawson (nateat_private)
Date: Tue Sep 17 2002 - 10:06:56 PDT

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    At 11:36 AM 9/10/2002 -0500, L. Adrian Griffis wrote:
     > I am aware of a company that has instituted a policy that limits a
     > specific character in people's passwords to being a numeric character.
     > Personally, I am confused at this policy.  It seems to me that
     > placing such a specific limit on a specific position in a password
     > simply reduces the number of guesses that someone would have to try
     > in a brute force attack.
     >
     > Does anyone out there know if there is any theoretical basis for
     > believing that a policy to limit a specific character position
     > in passwords to a numeric character will enhance security.  If not,
     > does anyone know how such a misunderstanding might have occurred?
     >
     > Adrian
    
    This is a bad idea.  Ross Anderson's group did a good study on different
    password selection approaches:
    http://www.cl.cam.ac.uk/ftp/users/rja14/tr500.pdf
    http://www.cl.cam.ac.uk/~jy212/pro-check.pdf
    
    -Nate
    



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