Compiling & Proving

Interact with the proving service for your Brevis app.

This section applies if your Brevis app uses the "pure-ZK" model. If you want to deploy your Brevis app under the coChain model, you may skip this section.

We recommend to host your circuit as a separate process as it can take up much more computing resource than typical web servers.

Spin Up a Prover for Your AppCircuit

The fastest way to spin up a prover is to use the prover service module in the Go SDK. prover.NewService automatically compiles your circuit and sets up proving/verifying keys if your circuit changes or if it's your first time compiling. Read more about Prover Service.

main.go

proverService, err := prover.NewService(&AppCircuit{}, config)
// listen to port 33247
proverService.Serve(33247)

You can also opt for manually compile & prove with Go

Calling the Prover From Node.js

High-level system diagram

Sending the Proof Request to Your Prover

const proofRes = await prover.prove(proofReq);

Error handling

if (proofRes.has_err) {
    const err = proofRes.err;
    switch (err.code) {
    case ErrCode.ERROR_INVALID_INPUT:
        console.error('invalid receipt/storage/transaction input:', err.msg);
        // handle invalid data input...
        // this error means some of your input
        // data (receipt/storage/transaction) is not found or not supported
        // e.g. you added a transaction of type other than 0 or 2
        break;

    case ErrCode.ERROR_INVALID_CUSTOM_INPUT:
        console.error('invalid custom input:', err.msg);
        // handle invalid custom input assignment...
        break;

    case ErrCode.ERROR_FAILED_TO_PROVE:
        console.error('failed to prove:', err.msg);
        // handle failed to prove. usually marking some record as failed
        break;
    }
}

If you receive ERROR_INVALID_INPUT, check your data against Limits and Performance to see if any data exceeds the limits.

Tip

If you want to reuse the proofs you can do serialize and deserialize ProveResponse by:

import { ProveResponse } from 'brevis-sdk-typescript';
const serialized = proofRes.serialize();
const restored = ProveResponse.deserialize(serialized)

Sending Your Proof to Brevis

import { Brevis } from 'brevis-sdk-typescript';

// A client for interacting with Brevis' systems
const brevis = new Brevis('appsdkv3.brevis.network:443');
// submit() takes 
// the proof request
// proof response
// source chain ID where the data you want to use in your computation is from
// destination chain ID where your want to post the proof to
const brevisRes = await brevis.submit(proofReq, proofRes, 1, 11155111);

const id = brevisRes.id;
const fee = brevisRes.fee;
console.log(id, fee)

Pay for Your Request on the Data Source Chain

Call BrevisRequest.sendRequest() with the id acquired from brevisRes and the fee (in native token). contract addresses

Note that this step is not needed if your application is partnered with a Brevis prover that serves off-chain requests.

Wait for Your App Contract to be Called

Since Brevis calls your app contract's callback function when the final proof is submitted, you can listen to your app contract's event. Or, you could use the built-in function to wait for the final transaction submission.

// wait() takes the request id and a destination chain id
brevis.wait(brevisRes.id, 11155111);