> Play the PKI Zero to Hero game in your browser: the Royal Exam and Levels 1 and 2 are available now, on desktop and phone. The other 25 levels are in development. Source: https://pkizerotohero.com/play/ The game · early access # Learn PKI by playing Keystone is a pixel-art town you walk through with Ken and Rosa. Every building is one lesson, and in every level you do the real thing: encrypt, sign, verify, build a chain, renew in time. [Play now](https://pkizerotohero.com/play/game/)[Meet the cast](https://pkizerotohero.com/cast/) Plays in your browser, on desktop and phone. No sign-up. Early access ## Available now - [Level 0The Royal ExamRoyal Exam HallPlay now](https://pkizerotohero.com/play/game/) - [Level 1The secret keyHarbour Post OfficePlay now](https://pkizerotohero.com/play/game/) - [Level 2The key-sharing problemCourier StablesPlay now](https://pkizerotohero.com/play/game/) In developmentThe other 25 levels are in development and will be released soon. Where it starts ## The Royal Exam The first thing you play. In the Royal Exam Hall on the town's plaza, Rosa hosts and Ken answers ten short questions drawn from every part of PKI. After every answer you see the right one and one plain sentence of why, so you leave knowing ten true things. - **10 questions**Three options each, plus a practice round that is not scored. - **About 7 to 10 minutes**No timer, and nothing to sign up for. - **A rank**Apprentice, Squire, Knight or Hero, on a card you can share without spoilers. - **A map of what to learn**Each question you missed lights up the building in town that teaches it. [Take the Royal Exam](https://pkizerotohero.com/play/game/) Prefer reading? The [crash course](https://pkizerotohero.com/course/) covers the same ground in ten short lessons, with check questions. How a level works ## Explain, show, then you do it Every level teaches one idea in the same rhythm, with every line advanced by you and nothing on a timer while you learn. 1. ### The idea, in real words A short story moment, then the real names of the parts: secret key, public key, certificate. 2. ### Watch it done Ken or Rosa does the operation step by step, with every step labelled. 3. ### Do it yourself The tempting wrong move is playable too, and you see its real consequence. 4. ### Prove it, then play A short untimed quiz, then an optional arcade challenge with relaxed, normal and no-timer modes. The town of Keystone ## 27 levels in eight districts The districts ring the Royal Plaza in the order you learn. Rosa will be crowned in thirty days, and the kingdom's trust must run on maths, not wax seals. Levels 1 to 26 each match a handbook chapter you can read today. ### Royal Plaza: where it starts The Royal Exam Hall with its gold dome, in the middle of town. - 0The Royal ExamRoyal Exam Hall: ten questions that show what you already know[Play now](https://pkizerotohero.com/play/game/) ### IHarbour Quarter: Secrets Docks, the post office, the stables and the lighthouse. - 1[The secret key](https://pkizerotohero.com/handbook/symmetric-encryption/)Harbour Post Office[Play now](https://pkizerotohero.com/play/game/) - 2[The key-sharing problem](https://pkizerotohero.com/handbook/key-distribution/)Courier Stables[Play now](https://pkizerotohero.com/play/game/) - 3[Two keys: the open padlock](https://pkizerotohero.com/handbook/key-pairs/)The LocksmithIn development - 4[Agreeing a secret in public](https://pkizerotohero.com/handbook/key-exchange/)The LighthouseIn development ### IIMarket Square: Proof The scribes, the signet workshop and the town gate. - 5[Fingerprints](https://pkizerotohero.com/handbook/hashes/)Scribes' HallIn development - 6[The signature](https://pkizerotohero.com/handbook/digital-signatures/)Signet WorkshopIn development - 7[The impostor](https://pkizerotohero.com/handbook/binding-identity/)The Town GateIn development ### IIIChancery Row: Certificates The notary, the registry, the petition office and the surveyors. - 8[The certificate](https://pkizerotohero.com/handbook/x509-certificates/)Royal NotaryIn development - 9[Names and jobs](https://pkizerotohero.com/handbook/names-and-key-usage/)Name RegistryIn development - 10[Asking for a certificate](https://pkizerotohero.com/handbook/csr/)Petition OfficeIn development - 11[Proving you own the name](https://pkizerotohero.com/handbook/domain-validation/)Surveyors' OfficeIn development ### IVCastle Approach: Trust and HTTPS The registry of roots, the chain bridge, the crossroads inn and the barbican. - 12[Who do we trust?](https://pkizerotohero.com/handbook/trust-stores/)Registry of RootsIn development - 13[The chain](https://pkizerotohero.com/handbook/certificate-chains/)Chain BridgeIn development - 14[Two roads to the same root](https://pkizerotohero.com/handbook/cross-signing/)Crossroads InnIn development - 15[The handshake](https://pkizerotohero.com/handbook/tls-handshake/)The BarbicanIn development ### VWatchtower Hill: When trust breaks The watchtower, the public ledger hall and the old archive. - 16[Taking it back](https://pkizerotohero.com/handbook/revocation/)WatchtowerIn development - 17[Everyone can see](https://pkizerotohero.com/handbook/certificate-transparency/)Public Ledger HallIn development - 18[Famous failures](https://pkizerotohero.com/handbook/famous-failures/)Old ArchiveIn development ### VIClockwork Works: Running PKI The clocktower, the robot workshop, the royal vault and the chancery. - 19[Expiry day](https://pkizerotohero.com/handbook/certificate-lifecycle/)ClocktowerIn development - 20[Robots that renew](https://pkizerotohero.com/handbook/acme/)Robot WorkshopIn development - 21[Guarding the crown jewels](https://pkizerotohero.com/handbook/hsm-and-key-ceremonies/)Royal VaultIn development - 22[A CA of your own](https://pkizerotohero.com/handbook/private-ca/)The ChanceryIn development ### VIIGuild Quarter: Beyond the browser The guild hall, the printing press and the clockmaker's factory. - 23[Both sides show ID](https://pkizerotohero.com/handbook/mutual-tls/)Guild HallIn development - 24[Signed and sealed](https://pkizerotohero.com/handbook/code-signing/)Printing PressIn development - 25[Machines with passports](https://pkizerotohero.com/handbook/device-identity/)Clockmaker's FactoryIn development ### VIIICastle Heights: The future The observatory and the Throne Hall. - 26[The quantum storm](https://pkizerotohero.com/handbook/post-quantum/)ObservatoryIn development - 27The coronationThrone Hall: make your own key pair and request a real certificateIn development Before you play ## Keyboard, touch or gamepad The game runs in your web browser, on a desktop or laptop and on a phone or tablet. There is nothing to install. - **Keyboard**The arrow keys or WASD walk, Space or Enter chooses, and Esc opens the menu. - **Touch**Hold an on-screen arrow to walk and tap the buttons. Phones work upright and sideways. - **Gamepad**A standard gamepad works too: the left stick walks and the buttons choose. - **Your progress**Saved in this browser. Settings has larger text, up to 200%. ## Watch the teaser [Download the 30-second teaser (MP4)](https://pkizerotohero.com/media/pkizth-teaser-30s.mp4) 30 seconds, music and sound effects only; every word appears on screen. Rosa seals an order with her ring, which stands for her private key. Ken checks the seal with her public key. Smudge changes one word, and the check fails. Your browser makes the same kind of check for every website. ## Learn the real thing, in the same order Everything the game teaches, including the levels still in development, is already here in plain words. About 90 minutes ### [Take the crash course](https://pkizerotohero.com/course/) Ten short lessons for the big picture, with check questions. Start lesson 1 One chapter per level ### [Read the handbook](https://pkizerotohero.com/handbook/) From a single shared secret to post-quantum cryptography, in 26 chapters. Start reading In your browser ### [Try the tools](https://pkizerotohero.com/tools/) Decode a certificate, check a chain, match a hostname or paste your error. Open the tools ## Get notified about new levels The kingdom is still being built. Send us an email and we will let you know when new levels are released. [Notify me about new levels](mailto:info@pkizerotohero.com?subject=Notify%20me%20about%20new%20levels%20of%20PKI%20Zero%20to%20Hero)