title: Creative uses for cryptography beyond the usual encryption/authentication
body: <p>Lately I've been intrigued by some of the less traditional uses of cryptography. Things like:</p>
  
  <ul>
  <li><a href="http://blog.notdot.net/2007/9/Damn-Cool-Algorithms-Part-2-Secure-permutations-with-block-ciphers" rel="nofollow noreferrer">making invoice numbers unpredictable</a></li>
  <li><a href="http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?tp=&amp;arnumber=4447820" rel="nofollow noreferrer">rolling dice in a p2p game</a></li>
  <li><a href="http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=4755250" rel="nofollow noreferrer">shuffling a deck of cards in a p2p game</a></li>
  </ul>
  
  <p>What other applications of cryptography can you think of outside the usual realm of message authentication and confidentiality?</p>