ark-groth16-zkv-example

A simple example of submission of Groth16 proofs generated with ark-groth16 library to zkVerify chain in two possible ways:

• directly, via subxt library (requires having test tVFY tokens)
• indirectly, via the Relayer service (doesn't require tVFY tokens)

Overview

The example demonstrates how to:

1. Generate a Groth16 proof with ark-groth16 library.
2. Convert the generated artifacts into subxt datatypes.
3. Send a submit_proof extrinsic to zkVerify pallet_settlement_groth16 to have the proof verified on zkVerify.

Prerequisites

The program can be used to submit proof both to a local development zkVerify node, and to the actual zkVerify testnet. In the first case, instructions to locally run a node in development mode can be found inside zkVerify documentation. In the second case, you need to acquire some testnet tVFY tokens (e.g. using this faucet).

Downloading zkVerify SCALE metadata

subxt library uses SCALE metadata of the target chain to build a typed interface to interact with that chain. ZkVerify metadata are already committed in the repo here. They can be downloaded by installing subxt-cli and running the command

subxt metadata \
  --pallets="SettlementGroth16Pallet" \
  --runtime-apis="" \
  --format="bytes" \
  --url="https://volta-rpc.zkverify.io" \
  --output-file="zkverify-metadata.scale"

Build instructions

1. Clone the repository:

   git clone https://github.com/lgiussan/ark-groth16-zkv-example.git
   cd ark-groth16-zkv-example

2. Build the project:

   cargo build --release

Usage

There are three options for submitting proofs to zkVerify. All the following commands allow to specify the number of inputs (from 0 to 64) via the optional parameter --num-inputs (default is 1), and the curve (bn254, or bls12-381) via the optional parameter --curve (default is bn254).

Submitting proofs to local development zkVerify node

By default, the send-to-zkv command connects to a local instance of zkVerify running at 127.0.0.1:9944 and uses the pre-funded development alice account

./target/release/ark-groth16-zkv-example send-to-zkv

Submitting proofs to actual zkVerify testnet

Otherwise, if you want to send proofs to the real zkVerify testnet, you should set the ZKV_SERET_PHRASE to the secret phrase of your zkVerify testnet account, and specify the rpc endpoint url, like this:

ZKV_SECRET_PHRASE="bottom drive obey lake curtain smoke basket hold race lonely fit walk" \
    ./target/release/ark-groth16-zkv-example send-to-zkv --url="wss://volta-rpc.zkverify.io"

Submitting proofs via the relayer

A third option is to send proofs via the relayer service

RELAYER_API_KEY=<your-api-key> ./target/release/ark-groth16-zkv-example send-to-relayer