@circom:verifier

Compile circom source (inline text or a http/ipfs URL), run an in-place setup, and return the Solidity verifier source with the verification key embedded, ready to pipe into @contracts:solidity to deploy. groth16 setups are DEV-ONLY (no ceremony); plonk/fflonk setups are deterministic and production-grade given a real powers-of-tau.

⚗️ Experimental — available at next.evmcrispr.com.

Returns: string

Syntax

@circom:verifier(source ptau:<value> system:<value>)

Arguments

Name	Type	Description
`source`	`string`	circom source code, or a http(s)/ipfs URL to fetch it from
`ptau:`	`string`	Powers-of-tau: `ptau:dev` or `ptau:<url>` (default: auto-download a hez file sized to the circuit)
`system:`	`string`	Proof system: `system:groth16

Trusted setup

groth16 (default) setups are generated on the spot with no multi-party ceremony: anyone who reproduces the setup can forge proofs that the verifier accepts. Prototyping only.
system:plonk / system:fflonk setups are deterministic — no circuit-specific ceremony exists, and security reduces to the powers-of-tau alone. With a real ptau (the auto-downloaded Hermez ceremony files) the exported verifier is production-grade, at a higher verification gas cost than groth16. With ptau:dev any system is dev-only, since a local ptau is itself unceremonied.

Powers of tau

Option	Effect
(none)	Auto-download `powersOfTau28_hez_final_<p>.ptau` from the public Hermez ceremony, with `2^p` sized to the circuit (min `2^8`, cap `2^16`)
`ptau:dev`	Generate a local powers-of-tau (fast for small circuits; cap `2^12`)
`ptau:<url>`	Fetch a specific ptau file (http(s) or ipfs)

Setups are cached per (circuit, ptau option) for the session, and circom:prove --circom resolves through the same cache — so the verifier you deploy and the proofs you generate in one script always match.

Examples

load circom
load contracts

set $src <<<CIRCOM
pragma circom 2.0.0;
template Multiplier2() {
    signal input a;
    signal input b;
    signal output c;
    c <== a * b;
}
component main = Multiplier2();
CIRCOM

contracts:deploy $verifier @contracts:solidity(@circom:verifier($src ptau:dev))
circom:prove $proof --circom $src --ptau dev --inputs [[a 3] [b 11]]
set [$a $b $c $signals] @circom:proof($proof)
print "Valid:" @get($verifier "verifyProof(uint256[2],uint256[2][2],uint256[2],uint256[1])(bool)" $a $b $c $signals)

Includes

include statements are prefetched before compiling: absolute URLs as written, version-pinned npm paths (e.g. circomlib@2.0.5/circuits/poseidon.circom) from npm-registry tarballs verified against their published integrity hash, and relative includes when the including file lives at a URL. Unpinned npm paths throw (mutable content has no stable hash to verify), as do relative includes in inline source. The circom compiler wasm itself is verified against a repo-pinned hash before it runs.