Solitaire is a top-notch pencil-and-paper encryption system developed by Bruce Schneier. Here is the description in Schneier's own words: "Solitaire gets its security from the inherent randomness in a shuffled deck of cards. By manipulating this deck, a communicant can create a string of "random" letters that he then combines with his message. Of course Solitaire can be simulated on a computer, but it is designed to be implemented by hand. "Solitaire may be low-tech, but its security is intended to be high-tech. I designed Solitaire to be secure even against the most well-funded military adversaries with the biggest computers and the smartest cryptanalysts. Of course, there is no guarantee that someone won't find a clever attack against Solitaire, but the algorithm is certainly better than any other pencil-and-paper cipher I've ever seen." Simple system, easy to use, and relatively fast. WWW: https://metacpan.org/release/Crypt-Solitaire Seamus Venasse