README.md

This repository contains my own implementation of the solutions for the ZKP-MOOC-Lab 2023 project. All solutions within this fork are crafted, ensuring soundness and optimization for the majority.

I welcome fellow coders, learners, and enthusiasts to utilize this repository as a reference for their learning journey. Moreover, fostering a community-driven learning process is at the heart of this initiative. So, let's engage in discussions and send pull request for more efficient solutions.

My implementation on Task 2: Generate a zk-SNARK proof using snarkjs

The first 9 steps are skipped by leveraging existed powersOfTau28_hez_final_08.ptau file. I followed the step in snarkjs README

10. Compile the circuit

circom circuits/example.circom --r1cs --wasm --sym

11. View information about the circuit

snarkjs r1cs info example.r1cs

12. Print the circuit

snarkjs r1cs print example.r1cs example.sym

13. Export r1cs to json

snarkjs r1cs export json example.r1cs example.r1cs.json
cat example.r1cs.json

14. Calculate the witness

cd example_js
node generate_witness.js example.wasm ../input.json ../witness.wtns

// input.json

{"product":2261, "factors": [7, 17, 19]}

15. Setup using Groth16

snarkjs groth16 setup example.r1cs powersOfTau28_hez_final_08.ptau circuit_0000.zkey

16. Contribute to the phase 2 ceremony

snarkjs zkey contribute circuit_0000.zkey circuit_0001.zkey --name="1st Contributor Name" -v

17. Provide a second contribution

snarkjs zkey contribute circuit_0001.zkey circuit_0002.zkey --name="Second contribution Name" -v

18. Provide a third contribution using third party software

snarkjs zkey export bellman circuit_0002.zkey challenge_phase2_0003
snarkjs zkey bellman contribute bn128 challenge_phase2_0003 response_phase2_0003 -e="zkpmooc"
snarkjs zkey import bellman circuit_0002.zkey response_phase2_0003 circuit_0003.zkey -n="Third contribution name"

19. Verify the latest zkey

snarkjs zkey verify example.r1cs powersOfTau28_hez_final_08.ptau circuit_0003.zkey

20. Apply a random beacon & Generate the final zkey

snarkjs zkey beacon circuit_0003.zkey circuit_final.zkey 0102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f 10 -n="Final Beacon phase2"

21. Verify the final zkey

snarkjs zkey verify example.r1cs powersOfTau28_hez_final_08.ptau circuit_final.zkey

22. Export the verification key

snarkjs zkey export verificationkey circuit_final.zkey verification_key.json

23. Create the proof using Groth16

snarkjs groth16 prove circuit_final.zkey witness.wtns proof.json public.json

24. Verify the proof

snarkjs groth16 verify verification_key.json public.json proof.json

[Additional] Convert Verifier into a smart contract

Leveraging ZKP on blockchain ecosystem

# export the verifier as a Solidity smart-contract
snarkjs zkey export solidityverifier circuit_final.zkey verifier.sol

# use soliditycalldata to simulate a verification call
snarkjs zkey export soliditycalldata public.json proof.json