Secret Colors is a gentle introduction to cryptography. With hand-drawn imagery and gentle explanations of cryptography concepts, this book will captivate beginners of all ages and backgrounds. The annual autumn dance is being held in the forest, and two bunnies are deciding who they will ask to the dance. As they pass notes between each other in class, they realize they need a way of keeping their messages secret. They develop a technique that allows them to securely talk to each other without any chance of other bunnies listening in on their conversation. In doing so, the bunnies give us a memorable example of symmetric-key encryption and key exchange protocols that readers will find fascinating and useful.