circom-learning

A simple circom demo

From writing to proving circuits.

Generate and compute the circuit.

• Generate the rank 1 constraint system (r1cs). circom multiplier2.circom --r1cs --wasm

• Compute the witness. node generate_witness.js multiplier2.wasm input.json witness.wtns

Prove the circuit.

Using snarkjs we'll prove the circuit through the Groth16 zk-SNARK protocol.

Powers of Tau ceremony.

• Circuit independent. snarkjs powersoftau new bn128 12 pot12_0000.ptau -v snarkjs powersoftau contribute pot12_0000.ptau pot12_0001.ptau --name="First contribution" -v

• Circuit dependent. snarkjs powersoftau prepare phase2 pot12_0001.ptau pot12_final.ptau -v

• Generate zkey. snarkjs groth16 setup multiplier2.r1cs pot12_final.ptau multiplier2_0000.zkey snarkjs zkey contribute multiplier2_0000.zkey multiplier2_0001.zkey --name="1st Contributor Name" -v

• Export zkey. snarkjs zkey export verificationkey multiplier2_0001.zkey verification_key.json

• Generate the proof. snarkjs groth16 prove multiplier2_0001.zkey witness.wtns proof.json public.json