Why do you think it is so difficult?

All you need is a single secret on the server. Then you can compute a signature as the hash of the secret plus the outgoing state plus a random salt. The signature, salt, and state are emitted in the response. When a request comes in, verify its signature by comparing it to the hash of the server's secret plus the client's salt and state.

Easy as pie.

If you're paranoid, you can add timestamps, rotate secrets, and use public-key signatures, none of which makes the job much more difficult. And, even if you do consider it more difficult, why does it matter for the day-to-day web programmer? This stuff is part of the web-app framework and invisible to end programmers.

Cheers,
Tom

Tom Moertel : Blog / Talks / CPAN / LectroTest / PXSL / Coffee / Movie Rating Decoder

In reply to Re^4: Eliminate server-side state to obviate cookies by tmoertel
in thread "omniscient debugging" for Perl by spurperl

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.