The journal
Open the journal →The conversation starts in the journal — be the first to post.
About DRYAD
The DRYAD Numeral Cipher/Authentication System is a simple, paper cryptographic system employed by the U.S. military for authentication and for encryption of short, numerical messages. Each unit with a radio is given a set of matching DRYAD code sheets. A single sheet is valid for a limited time, called a cryptoperiod.
Everything about DRYAD →