Learn cryptography by breaking real ciphers, step by step.
New to ciphers? Start with the classics and work your way up — every cipher comes with guided learning and a breaking tool.
Already know your stuff? Jump straight to the tool — every cipher in the collection, no tracking, no accounts.
Never encrypted anything? Begin with the Caesar shift — the classic first cipher — and learn by breaking messages.
Climb from the trivial to Enigma. Every rung: a tool and a guided course.
✓ What's built
Ten cipher pages with guided learning tabs — tool, learn, history, practiceGuided cryptoanalysis wizards for Vigenère, ADFGVX, Affine, Playfair and AlbertiPractice challenges with difficulty-matched hint presets — in three languages→ What's next
More substitution ciphers — homophonic and keyword substitutionTransposition ciphers — rail fence and columnarThe Nihilist cipher — substitution meets transpositionPop-culture easter eggs — the Arne Saknussemm cipher