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noir:prove

Generate an UltraHonk proof with Barretenberg and bind the result (proof + public inputs, as JSON) to . Compile Noir source in-place (--noir) or prove from a pre-built compiled-program artifact (--artifact). Defaults to the keccak transcript so proofs verify on-chain against the @noir:verifier contract; read the verifier-call arguments back with @noir:proof.

⚗️ Experimental — available at next.evmcrispr.com.

Syntax

Section titled “Syntax”
noir:prove <variable>

Arguments

Section titled “Arguments”
NameTypeDescription
variablevariableVariable to bind the proof JSON string to

Options

Section titled “Options”
NameTypeDescription
--noirstringNoir source (or a http(s)/ipfs URL) to compile in-place instead of --artifact — single-file circuits with the stdlib only
--artifactstringURL (http(s):// or ipfs://) of a compiled Noir program artifact (nargo target/*.json or @noir:compile output); supports a #sha256=0x… integrity pin
--oraclestringProof transcript: keccak (default; verifiable on-chain by the @noir:verifier contract) or poseidon (bb's native transcript, off-chain use only)
--inputsanyCircuit inputs: an entries array like [[x 3] [y 11]] (nest values for array inputs), or a JSON object string (required for struct inputs)

Examples

Section titled “Examples”
# Prove a statement about a secret and check the proof off-chain — here: I know an x that differs from the public y
set $src <<<NOIR
fn main(x: Field, y: pub Field) {
    assert(x != y);
}
NOIR
noir:prove $proof --noir $src --inputs [[x 3] [y 5]]
print "Valid:" @noir:verify($proof @noir:vkey($src))

Inputs

Section titled “Inputs”

--inputs takes the circuit's main() parameters by name, as a record: [x:3 y:5] — sugar for the equivalent entries array [[x 3] [y 5]], which is accepted too. Values may be numbers, decimal or hex strings, booleans, or nested arrays for array parameters. A JSON object string is also accepted (quote it with single quotes), and is the only way to pass struct-typed inputs — the shape follows a Prover.toml converted to JSON.

Compiling in-place (--noir)

Section titled “Compiling in-place (--noir)”

--noir compiles the given source (inline heredoc or URL) with the bundled Noir compiler. Circuits are single-file with the stdlib (std::…) available; external Nargo [dependencies] are git-fetched by nargo itself and cannot be resolved here — inline the code instead. Compiles are cached per source for the session and shared with the @noir:* helpers, so the verifier a script deploys always matches the proofs it generates.

--artifact proves from a pre-built compiled-program JSON instead (a nargo target/*.json or hosted @noir:compile output). Append #sha256=0x… to the URL to pin the artifact's hash; ipfs:// content is already verified against its CID.

Oracles

Section titled “Oracles”

UltraHonk proofs commit to a transcript hash:

  • keccak (default): what the @noir:verifier Solidity contract expects — proofs verify both on-chain and off-chain.
  • poseidon: bb's native transcript — cheaper to prove, off-chain (@noir:verify) use only.

The bound proof JSON records its oracle, so @noir:verify always checks against the right transcript. Unlike groth16, UltraHonk needs no circuit-specific trusted setup — there is no ceremony to fake and no dev-only caveat.

Barretenberg downloads its SRS points (Aztec's ignition ceremony) from crs.aztec-labs.com on the first proof of a session and caches them.

See Also

Section titled “See Also”