Beginner
Cryptography
Hash visualizer
Type any text and see its SHA-256 fingerprint. Change one character and watch every bit change.
Interactive lab
Hands-on experiments for every core idea. Everything runs in your browser.
Beginner
Cryptography
Caesar cipher lab
Encrypt a message by shifting letters and see why this ancient cipher is trivial to break today.
Intermediate
Cryptography
Symmetric encryption
Encrypt and decrypt a message with AES-GCM and a passphrase, and see why the key matters.
Intermediate
Cryptography
Public-key cryptography
Generate a key pair and encrypt a message with the public key so only the private key can open it.
Advanced
Cryptography
Digital signature lab
Sign a message and verify it. Change the message and watch verification fail.
Beginner
Blockchain
Blockchain simulator
Build a chain of blocks, edit one, and see the whole chain become invalid.
Intermediate
Blockchain
Mining simulator
Find a nonce that makes the block hash meet a difficulty target — the essence of Proof of Work.
Intermediate
Blockchain
Merkle tree visualizer
Hash transactions into a tree and see how editing one leaf changes the root.
Beginner
Blockchain
Transaction visualizer
Follow a transaction from wallet to block and inspect each field.
Advanced
Blockchain
Consensus lab
Compare Proof of Work and Proof of Stake as networks agree on one history.