Cryptography is the art and science of securing communication. For millennia, humans have devised clever ways to hide messages from prying eyes — from Caesar's simple letter shifts to the Enigma machine of World War II. Today, cryptography underpins the entire digital economy: every HTTPS connection, every cryptocurrency transaction, every encrypted message relies on mathematical problems that are easy to compute but practically impossible to reverse.
These simulations let you explore cryptographic concepts hands-on. Shift letters with the Caesar cipher, watch how RSA uses prime numbers to create public-key encryption, understand why hash functions are one-way streets, and see how Diffie-Hellman lets strangers agree on a secret over a public channel.