CipherStreet: Code Puzzles

Crack real ciphers: Caesar to RSA - inside a cold-war spy thriller. Learn the foundations of modern cryptography by doing, not by being lectured. No ads, no tracking.

CipherStreet is a story-driven puzzle game where every level is a real cryptographic cipher - from Caesar shifts to RSA public keys - wrapped in a cold-war spy thriller.

Intercept encoded messages. Decode them with on-screen tools you discover, not tutorials you sit through. Unlock fragments of a decades-spanning conspiracy with every cipher you crack. By the end of ten chapters you'll have genuinely internalised the foundations of modern cryptography - roughly the first four weeks of a university course — without a single lecture.

THE STORY A defector known only as The Architect has built a private intelligence network hidden inside ever more sophisticated ciphers. Your handler, Agent Kovács, sends each intercept with minimal context and maximum urgency. A mole. A missing codebook. A name that keeps reappearing across fifty years. Crack the codes before dawn.

TEN CHAPTERS, TEN REAL CIPHERS • Caesar cipher: frequency analysis • Vigenère: the pattern inside the pattern • Rail Fence: transposition • Enigma (simplified): the crib attack that broke a war • Playfair: grid geometry • One-Time Pad: the perfect, unbreakable lock • Diffie-Hellman: sharing a secret in public • RSA: math as a lock • Hash functions: integrity, not secrecy • Steganography: messages hidden in plain sight

WHAT MAKES IT DIFFERENT • Learn by doing: tools are discovered through play, never explained at you • Real, historically accurate cryptography, all running offline on your device • A genuine spy narrative with characters, twists, and a finale that recasts everything • No punishing fail states: get a cipher wrong and the story simply waits • Build and share your own encrypted intercepts; challenge friends to crack them

FREE TO START Chapters 1–2 are completely free, no account required. A single one-time purchase unlocks chapters 3–10 and every cipher type in the Builder. No ads. No subscriptions. No tracking.

The cipher is never the weakest link. The human always is.