Encrypt / Hash
Watch your own message get encrypted — and see what's going on under the hood.
Type any string and watch it get hashed or encrypted with the algorithms below — every intermediate number on screen, nothing simulated. Each lab starts in step mode: you advance the computation one card at a time with Next, and each card explains what just happened and why before you move on.
Prefer to watch? Press ▶ Play and it runs start to finish, slowed down, with a speed control — plus a scrubber to drag back to anything you missed.
For the full story behind each algorithm — the history, the why, and every step demonstrated on your own values — hit Learn Cryptography at the top.
Hash with SHA-256
Watch your message get padded, sliced into blocks, expanded into a message schedule, and folded through 64 rounds of compression into a unique 256-bit fingerprint.
Open the lab →Encrypt with RSA
Pick two primes and build a real key pair — modulus, totient, public and private exponents — then watch your message get locked by one key and opened by the other.
Open the lab →Cipher with Caesar & Vigenère
Two thousand years in one deck: shift your message like Caesar, watch letter-counting break it, then rotate through a keyword's alphabets — every addition shown, letter by letter.
Open the lab →XOR & the one-time pad
Add bits without carry, build perfect secrecy, then reuse one pad and watch the secret cancel itself.
Open the lab →Enigma
Step three rotors per keypress, trace the electrical path, and expose the reflector's never-self clue.
Open the lab →AES-128
Transform a 4 × 4 byte state through ten real rounds—and derive the S-box instead of trusting a table.
Open the lab →ChaCha20
Follow add–rotate–XOR quarter-rounds through a word grid and turn the mixed state into a keystream.
Open the lab →Diffie–Hellman
Watch Alice and Bob derive one shared secret across a channel where every public value is visible.
Open the lab →Elliptic curves & ECDH
Draw point addition, walk scalar multiplication, and repeat Diffie–Hellman with short curve keys.
Open the lab →Signatures & HMAC
Give SHA-256 a key, turn an RSA digest into a signature, and reject a one-bit tamper.
Open the lab →TLS handshake capstone
Assemble certificates, key exchange, hashing, HMAC, and AES into the browser padlock.
Open the lab →