Introducing Mosaic: Glock's final piece
Mosaic realizes the Glock paper's vision at a low onchain cost.
Today we’re releasing Mosaic, a practical fault-proof verifier with production Rust code and security strong enough to host financial markets on Bitcoin.
Mosaic allows Alpen to verify arbitrary computation on Bitcoin securely and elegantly. It realizes the Glock paper vision at a low onchain cost, making the path from research primitive to production protocol much more concrete.
Read the preprint: Mosaic: Practical Malicious Security for Garbled Circuits on Bitcoin
Explore the codebase: github.com/alpenlabs/mosaic
Why Mosaic matters
Garbled circuits enable optimistic verification on Bitcoin. A prover commits to a circuit offchain. If the prover submits an invalid proof, the verifier can evaluate the circuit to recover a signature that serves as an onchain fault proof.
The challenge is proving that the garbled circuit was built honestly. The standard cryptographic answer is cut-and-choose: generate many garbled copies, open some at random, and keep the rest for evaluation.
On Bitcoin, that approach is expensive because each saved copy normally needs its own set of signatures posted onchain. Mosaic removes that scaling penalty by generating the copies in a structured way, so one set of onchain signatures can support evaluation across many copies.
More security costs more offchain work for the prover, but it does not require proportionally more permanent Bitcoin blockspace.
From Glock to production
Glock introduced the core idea. Mosaic fills in the production system around it: a protocol specification, security analysis, and a Rust implementation for the cryptography, networking, storage, and state management needed to operate the verifier.
With Mosaic, Alpen Mainnet can bring verifiable financial markets to Bitcoin with the security model that made Glock compelling in the first place.