Pals,

I'm rather fond of using long random strings as session ids, something like "Fa4ADX4dhd6f0ss7d6fkjl". These are generated by a mod_perl'd script, and are 20 alphanumeric, mixed capital characters.

I don't MD5 hash them, because they have no value except to identify the user as unique in a cookie I set.

I've heard in the past somewhere that this isn't a good idea. Can someone explain to me why? I'm a perl hacker, not a cryptographer, so please keep that in mind in your explanation.

I generate the session ids infrequently enough (e.g. only when a user logs in) and I'm not opposed to using a more processor intensive method to create them, if there's solid reasons to do so.

Thanks in advance!

-Any sufficiently advanced technology is
indistinguishable from doubletalk.

In reply to Secure Session ID values by Hero Zzyzzx

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.