groth16-solana

Reusable Groth16 verifier template for Solana. One deployed program verifies any Circom circuit — verifying keys live in content-addressed PDAs, no redeploy per circuit.

Walkthrough →

Contents

• Anchor program with initialize_vk and verify_proof
• ts/src/reshape.ts — snarkjs JSON → canonical on-chain bytes
• CLIs: upload-vk.ts, verify.ts
• Example circuits: preimage (1 input), range (2 inputs)
• 10 unit + 10 integration + 3 measurement tests

Prerequisites

# Rust 1.89+
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

# Solana CLI 3.x
sh -c "$(curl -sSfL https://release.anza.xyz/stable/install)"

# Anchor 1.0
cargo install --git https://github.com/coral-xyz/anchor avm --locked
avm install latest && avm use latest

# Circom 2.2
cargo install --git https://github.com/iden3/circom.git circom

# pnpm + snarkjs (Node 24+ from nodejs.org)
npm install -g pnpm snarkjs

Local validator: surfpool (or solana-test-validator).

Quick start

git clone <repo-url> && cd groth16-solana
pnpm install
bash scripts/setup.sh
anchor build && anchor keys sync && anchor build
anchor test
bash scripts/example.sh

Expected output from example.sh:

[preimage] circuit_id=<64 hex chars>
verified: true
[range] circuit_id=<64 hex chars>
verified: true

Bring your own circuit

Assume your circuit lives at circuits/mycircuit/circuit.circom.

1. Compile and run Phase-2 ceremony.

cd circuits/mycircuit
circom circuit.circom --r1cs --wasm --sym -l ../../node_modules/circomlib/circuits
snarkjs groth16 setup circuit.r1cs ~/.cache/ptau/powersOfTau28_hez_final_17.ptau circuit_0.zkey
echo "entropy" | snarkjs zkey contribute circuit_0.zkey circuit_final.zkey
snarkjs zkey export verificationkey circuit_final.zkey verification_key.json

2. Generate witness and proof.

node circuit_js/generate_witness.js circuit_js/circuit.wasm input.json witness.wtns
snarkjs groth16 prove circuit_final.zkey witness.wtns proof.json public.json
cd ../..

3. Start a local validator and deploy.

surfpool start &
until solana cluster-version >/dev/null 2>&1; do sleep 1; done
solana airdrop 100 && anchor deploy

4. Upload the VK. Returns the content-addressed circuit_id.

CID=$(pnpm -s exec tsx ts/src/upload-vk.ts --vk circuits/mycircuit/verification_key.json)

5. Verify the proof on-chain.

pnpm -s exec tsx ts/src/verify.ts --circuit-id "$CID" --proof circuits/mycircuit/proof.json --public circuits/mycircuit/public.json

One-shot upload ceiling is 4 public inputs (see artifacts/measurements.json). Larger circuits require chunked upload (not implemented).

Measurements

Metric	Value
verify_proof CU (preimage)	90,650
verify_proof CU (range)	95,979
One-shot initialize_vk max public inputs	4

Attribution

programs/verifier/src/vendor/ is vendored from Lightprotocol/groth16-solana@54f2cfc3, modified only to remove the NR_INPUTS const generic. Upstream license at LICENSE-UPSTREAM.

License

MIT