Introduction

An example repo to verify Noir circuits (with bb backend) using a Solidity verifier.

• /circuits - contains the Noir circuits.
• /contract - Foundry project with a Solidity verifier and a Test contract that reads proof from a file and verifies it.
• /js - JS code to generate proof and save as a file.

Tested with Noir 1.0.0-beta.3 and bb 0.82.2

Installation / Setup

# Foundry
git submodule update

# Build circuits, generate verifier contract
(cd circuits && ./build.sh)

# Install JS dependencies
(cd js && yarn)

Proof generation in JS

# Use bb.js to generate proof and save to a file
(cd js && yarn generate-proof)

# Run foundry test to read generated proof and verify
(cd contract && forge test --optimize --optimizer-runs 5000 --gas-report -vvv)

Proof generation with bb cli

cd circuits

# Generate witness
nargo execute

# Generate proof
bb prove -b ./target/noir_solidity.json -w target/noir_solidity.gz -o ./target --oracle_hash keccak

# Split this proof and public inputs into two files

# Convert proof to hex, and slice first 4 bytes of metadata
PROOF_HEX=$(cat ./target/proof | od -An -v -t x1 | tr -d $' \n' | sed 's/^.\{8\}//')

NUM_PUBLIC_INPUTS=1
HEX_PUBLIC_INPUTS=${PROOF_HEX:0:$((32 * $NUM_PUBLIC_INPUTS * 2))}
SPLIT_HEX_PUBLIC_INPUTS=$(sed -e 's/.\{64\}/0x&,/g' <<<$HEX_PUBLIC_INPUTS)
PROOF_WITHOUT_PUBLIC_INPUTS="${PROOF_HEX:$((NUM_PUBLIC_INPUTS * 32 * 2))}"

# Save proof and public inputs to files
echo $PROOF_WITHOUT_PUBLIC_INPUTS | xxd -r -p > ./target/proof
echo "[\"$SPLIT_HEX_PUBLIC_INPUTS\"]" > ./target/public-inputs

# Run foundry test to read generated proof and verify
cd ..
(cd contract && forge test --optimize --optimizer-runs 5000 --gas-report -vvv)

Deployment

Deploying to base Sepolia:

forge script script/Deploy.s.sol:DeployScript --rpc-url https://mainnet.base.org --broadcast --legacy

Deployment output:

Verifier deployed at: 0x519845DF3Ead9be1B1217d422f5b40a4d43e737D
Starter deployed at: 0xaf78eFEf8B958eBa80D64e78fdBE655DC58e133b
Total Paid: 0.00000522658568628 ETH (5224287 gas * avg 0.00100044 gwei)

Verifying Proof onchain

Verify proof on base Sepolia:

forge script script/VerifyProof.s.sol:VerifyProofScript --rpc-url https://mainnet.base.org --broadcast --legacy

Here is a sample tx - Transaction Fee: 0.000011818559069182 ETH ($0.02)

Get number of verified proofs on-chain

forge script script/VerifyProof.s.sol:GetVerifiedCount --rpc-url https://mainnet.base.org --broadcast --legacy

Cost on Base Mainnet

Verifier deployed at: 0x519845DF3Ead9be1B1217d422f5b40a4d43e737D Starter deployed at: 0xaf78eFEf8B958eBa80D64e78fdBE655DC58e133b

Deployment cost of verifier contract: 0.000028411358047473 ETH ($0.11 when ETH = ~3800 USD) - Sample TX

Proof verification cost : 0.000009590438665493 ETH ($0.04 when ETH = ~3800 USD) - Sample Tx