Dive into the secret history of . . . secrets! Cryptology is the art and science of secret communication, and its purpose is to protect precious information and keep people safe. Learn about its building blocks: ciphers, codes, and keys. People have wanted to hide messages and important information for millennia. Read how history's coolest codes and ciphers have progressed from belts and sticks to rotating disks and supercomputers. Use your cryptology skills to design your own secret cipher. And learn about the smart people who built and broke the strongest secret systems.