Today we are pleased to announce that RISC Zero’s zkVM has joined the pantheon of systems that can run DOOM. You can checkout the source code here.

Here’s how it works: the user runs our DOOM port in the zkVM and provides a “demo” file (a transcript of their game inputs) as input. DOOM then replays the demo file, and as it does so, renders the in-game graphics to the zkVM’s journal (a cryptographically signed and verifiable output log) which can then be displayed onscreen. The GIF shown above was generated by capturing these frames.

Because DOOM is running in the zkVM, we obtain a ZK proof that the frames contained in the journalreally did come from DOOM. And because it’s a zero knowledge proof, no information about the demo file gets revealed (beyond that which can be seen onscreen).