A stick figure guide to the Advanced Encryption Standard. [via Bruce Schneier]
posted by Electric Dragon on Sep 26, 2009 - 21 comments

XKCD author Randall Munroe appears to have left a neat little cryptographic puzzle for Reddit users in his new book. They're trying to decipher it.
posted by zarq on Sep 21, 2009 - 44 comments

Thomas Jefferson's cipher message from Robert Patterson For more than 200 years, buried deep within Thomas Jefferson's correspondence and papers, there lay a mysterious cipher -- a coded message that appears to have remained unsolved. Until now.... To Mr. Patterson's view, a perfect code had four properties: It should be adaptable to all languages; it should be simple to learn and memorize; it should be easy to write and to read; and most important of all, "it should be absolutely inscrutable to all unacquainted with the particular key or secret for decyphering." [more inside]
posted by caddis on Jul 2, 2009 - 22 comments

In March 2007, the FermiLab Office of Public Affairs in Batavia, IL "received a curious message in code" via USPS. In May 2008, scientists posted a facsimile image of the letter to their blog in the hopes of soliciting cryptologists to decipher the letter. [more inside]
posted by subbes on Jul 16, 2008 - 45 comments

If you work at Langley and you need a break from actual intelligence gathering, you can always try to crack the code to the sculpture right outside the cafeteria window. Kryptos is a sculpture by James Sanborn located on the CIA grounds which contains a four-part coded message: sections 1-3 have been solved (with Sanborn admitting he made a typo in section 2). Perhaps you'd like to join Elonka (and the hive mind) in having a go at section 4.
posted by goodnewsfortheinsane on Dec 3, 2006 - 14 comments

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posted by Plutor on Jul 5, 2005 - 69 comments