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# Groth16

This library implements a verifier for the Groth16 protocol over the BN_254 elliptic curve.

## Example

```rust
use risc0_groth16::{ProofJson, PublicInputsJson, Verifier, VerifyingKeyJson};

const TEST_VERIFICATION_KEY: &str = test_data!("verification_key.json");
const TEST_PROOF: &str = test_data!("proof.json");
const TEST_PUBLIC_INPUTS: &str = test_data!("public.json");

fn verify() {
    let verifying_key: VerifyingKeyJson = serde_json::from_str(TEST_VERIFICATION_KEY).unwrap();
    let proof: ProofJson = serde_json::from_str(TEST_PROOF).unwrap();
    let public_inputs = PublicInputsJson {
        values: serde_json::from_str(TEST_PUBLIC_INPUTS).unwrap(),
    };
    let verifier = Verifier::from_json(proof, public_inputs, verifying_key).unwrap();
    verifier.verify().unwrap();
}
```

## STARK to SNARK

It also provides the [stark_to_snark][docker::stark_to_snark] function to run a prover Groth16
recursion prover via Docker. After generating a RISC Zero STARK proof, this function can be
used to transform it into a Groth16 proof. This function becomes available when the `prove`
feature flag is enabled.

> IMPORTANT: This feature requires an x86 architecture and Docker installed.
> Additionally, specific [installation steps](https://github.com/risc0/risc0/tree/main/groth16_proof) must be followed to use this functionality.

The recommended way to get a Groth16 proof is to use the `Prover` trait in the [risc0-zkvm]
crate. With `ProverOpts::groth16()` it will produce a Groth16 proof.

[risc0-zkvm]: https://docs.rs/risc0-zkvm/latest/risc0_zkvm/

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