4 ms·

See also http://en.wikipedia.org/wiki/Solitaire_(cipher) http://en.wikipedia.org/wiki/Solitaire_(cipher) which uses a deck as an innocent-looking keystream havi

• eddington 15y ago
  It should be noted Solitaire is not secure for long messages. http://www.ciphergoth.org/crypto/solitaire/ http://www.ciphergoth.org/crypto/solitaire/
• Cushman 15y ago
  What's really cool about Solitaire is not so much that it uses the deck as a RNG and keystream, but that it uses the deck as a computational tool. You can easily sit down and securely encrypt a (relatively) long message without writing down anything but the cipher text. The algorithm is also pretty straightforward. I learned to do it a couple years ago-- if you're interested in crypto and get invited to parties, it makes a neat party trick. It took a couple of hours, maybe, before I could do a couple characters a minute. I'm sure I've forgotten the specifics by now, though; it's not something that comes up a lot in day-to-day life :)