Proving: Circuit building
Corset is part of the LinethLineth (Formerly the Linea Stack) The open-source ZK-rollup stack, codebase, and technical protocol that's the foundation of Linea Mainnet. Operators can deploy this stack to launch their own Ethereum-compatible L2 or L3 networks. prover. It performs the first stage of the proving system: it compiles Lineth's zkEVMzkEVM A virtual machine that executes smart contracts and proves the correctness of execution using zero-knowledge proofs. zkEVMs recreate aspects of Ethereum's design, which provides an "Ethereum-like" experience for developers and users. rules into a constraint system, and prepares each batch's execution traces so the prover can check them against that system.
A constraint system is a set of rules that a computation must satisfy. Proving in zero knowledge means showing that some data satisfies every rule in the system, without revealing the data itself.
How it works
Corset runs at two different times.
At build time, it compiles Lineth's arithmetization: the constraint definitions, written in a Lisp domain-specific language, that describe what correct zkEVM execution looks like. The compiled constraint system is bundled into the prover, so a change to the arithmetization reaches the prover as a new build rather than at runtime.
At runtime, it expands the conflated traces that the tracer produced for a batch. Trace expansion derives the columns the constraint system checks from the columns the tracer recorded, producing the complete data set, or witness, that the prover proves against.
See also
- See Circuit execution and runtime for the second stage of the proving system, where gnarkgnark A software library that offers users the ability to design and run computational circuits in zk-SNARKs through a high-level API. turns the witness into a proof.
- See Module limits for the per-module trace line limits that keep an expanded trace within what the prover can handle.
- See the
go-corsetsource code, and Lineth's constraint definitions in thelineth-monorepo.