A lookup table doesn't help you if the (MD5) hashing is set up correctly:

my $secret = "Secret Passphrase";
my $password = get_password;
my $salt = get_username;

die unless $password;
die unless $salt;

my $md5 = md5($secret.$password.$salt);

[download]

That way, as long as the $secret remains secret, the hash lookup cannot be reversed to something you would enter in the password entry field, unless all entries in the hash lookup list have the same (secret) prefix.

Of course, if you can create enough users (and passwords), you can try an attack to recover $secret.

In reply to Re: OT: Cracking hashes made easier by Corion
in thread OT: Cracking hashes made easier by zentara

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.