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ACIR — Abstract Circuit Intermediate Representation

Description

The intermediate representation used by Noir. ACIR is a backend-agnostic circuit representation that sits between Noir's frontend (Rust-like language) and the backend prover (e.g., Barretenberg). It supports both arithmetic constraints and "blackbox" functions (SHA-256, ECDSA, etc.) that are handled natively by the backend. This separation lets Noir target multiple proving backends.

Used by Proof Systems

UltraHonk (via Barretenberg)

Supported by Tools

Noir, Barretenberg

Resources

• Spec: noir-lang-noir
• Explainer: