Learn Cryptography
Read how it works. Then watch it work on your values.
Each write-up below tells the whole story of an algorithm — the problem it solves, where it came from, how the machinery turns, and where it guards the world today.
And these aren't textbook pages: at the top of each one you enter your own message (and, for RSA, your own primes). Every section then pairs its explanation with a live demo of your values being manipulated at exactly that step — advance each one card by card, or press play and watch it run.
Ready to drive the full computation yourself? That's the Encrypt / Hash section.
The story of SHA-256
Fingerprints for data: what a hash promises, the rise and fall of MD5 and SHA-1, nothing-up-my-sleeve numbers, 64 rounds of mixing, and the avalanche effect — demonstrated on your message.
Read & explore →The story of RSA
The padlock anyone can close: the key-distribution problem, the 1970s race that solved it, why factoring is the wall, and the road to a quantum-resistant future — demonstrated on your primes.
Read & explore →The story of Caesar & Vigenère
Where it all began: Caesar's shift, al-Kindi's letter-counting attack, the keyword cipher that held for three centuries, and the break that taught cryptography its oldest lesson — on your message.
Read & explore →XOR & perfect secrecy
Why one bit operation can build an unbreakable cipher—and why one reused pad destroys it.
Read & explore →Inside Enigma
Changing substitution alphabets, rotor stepping, cribs, procedures, and the reflector's structural leak.
Read & explore →How AES-128 works
The modern symmetric workhorse, its derived S-box, finite-field mixing, key schedule, and ten rounds.
Read & explore →How ChaCha20 works
A modern stream cipher built from simple ARX operations—and the nonce rule inherited from one-time pads.
Read & explore →The Diffie–Hellman exchange
How two parties create the same secret publicly, why discrete logs matter, and why identity is still missing.
Read & explore →Elliptic curves & ECDH
From line-and-reflect geometry to finite fields, scalar multiplication, short keys, and a shared point.
Read & explore →Hashes, HMAC & signatures
Fair treatment for each promise: fingerprints, shared-key authenticity, public verification, and tamper failure.
Read & explore →The TLS handshake
The capstone: watch every earlier machine cooperate to authenticate, agree, derive, encrypt, and verify.
Read & explore →