FAQ 8.11 How do I decode encrypted password files?



This message is one of several periodic postings to comp.lang.perl.misc
intended to make it easier for perl programmers to find answers to
common questions. The core of this message represents an excerpt
from the documentation provided with Perl.

--------------------------------------------------------------------

8.11: How do I decode encrypted password files?

You spend lots and lots of money on dedicated hardware, but this is
bound to get you talked about.

Seriously, you can't if they are Unix password files--the Unix password
system employs one-way encryption. It's more like hashing than
encryption. The best you can check is whether something else hashes to
the same string. You can't turn a hash back into the original string.
Programs like Crack can forcibly (and intelligently) try to guess
passwords, but don't (can't) guarantee quick success.

If you're worried about users selecting bad passwords, you should
proactively check when they try to change their password (by modifying
passwd(1), for example).



--------------------------------------------------------------------

Documents such as this have been called "Answers to Frequently
Asked Questions" or FAQ for short. They represent an important
part of the Usenet tradition. They serve to reduce the volume of
redundant traffic on a news group by providing quality answers to
questions that keep coming up.

If you are some how irritated by seeing these postings you are free
to ignore them or add the sender to your killfile. If you find
errors or other problems with these postings please send corrections
or comments to the posting email address or to the maintainers as
directed in the perlfaq manual page.

Note that the FAQ text posted by this server may have been modified
from that distributed in the stable Perl release. It may have been
edited to reflect the additions, changes and corrections provided
by respondents, reviewers, and critics to previous postings of
these FAQ. Complete text of these FAQ are available on request.

The perlfaq manual page contains the following copyright notice.

AUTHOR AND COPYRIGHT

Copyright (c) 1997-2002 Tom Christiansen and Nathan
Torkington, and other contributors as noted. All rights
reserved.

This posting is provided in the hope that it will be useful but
does not represent a commitment or contract of any kind on the part
of the contributers, authors or their agents.
.



Relevant Pages

  • FAQ 3.16 How can I make my Perl program run faster?
    ... This message is one of several periodic postings to comp.lang.perl.misc ... intended to make it easier for perl programmers to find answers to ... from the documentation provided with Perl. ... Asked Questions" or FAQ for short. ...
    (comp.lang.perl.misc)
  • FAQ 8.26 Why doesnt open() return an error when a pipe open fails?
    ... This message is one of several periodic postings to comp.lang.perl.misc ... intended to make it easier for perl programmers to find answers to ... from the documentation provided with Perl. ... Asked Questions" or FAQ for short. ...
    (comp.lang.perl.misc)
  • FAQ 3.19 How can I make my CGI script more efficient?
    ... This message is one of several periodic postings to comp.lang.perl.misc ... intended to make it easier for perl programmers to find answers to ... from the documentation provided with Perl. ... Asked Questions" or FAQ for short. ...
    (comp.lang.perl.misc)
  • FAQ 3.19 How can I make my CGI script more efficient?
    ... This message is one of several periodic postings to comp.lang.perl.misc ... intended to make it easier for perl programmers to find answers to ... from the documentation provided with Perl. ... Asked Questions" or FAQ for short. ...
    (comp.lang.perl.misc)
  • FAQ 3.20 How can I hide the source for my Perl program?
    ... This message is one of several periodic postings to comp.lang.perl.misc ... intended to make it easier for perl programmers to find answers to ... from the documentation provided with Perl. ... Asked Questions" or FAQ for short. ...
    (comp.lang.perl.misc)