sai-c / zkpy

A Python library that allows for easy compiling/proving/verifying of zk circuits.

zkpy

A Python library that allows for easy compiling/proving/verifying of zk circuits.

Overview

ZKPy is a Python library that allows for easy compiling/proving/verifying of zk circuits. It is implemented as a wrapper of Circom or SnarkJS, allowing developers to incorporate zero knowledge proofs into Python projects.

Features:

• Can perform trusted setup (Powers of Tau and Phase 2)
• Can generate proofs for circuits written in Circom
• Can verify proofs given witness file and verification key
• Implements both Groth16 and PLONK proving schemes

Dependencies

zkpy requires Circom and snarkjs. You can find installation instructions here.

Installation

The recommended way to install zkpy is through pip.

pip install zkpy

Usage

Powers of Tau

Start by importing PTau:

from zkpy.ptau import PTau

Here is an example use case walking through a powers of tau ceremony: First, create PTau object:

ptau = PTau()

Initialize powers of tau ceremony:

ptau.start() 

Make first contribution:

ptau.contribute()

Make second contribution with a name and specified entropy:

ptau.contribute(name="second", entropy="random text") 

Apply beacon to finalize powers of tau ceremony:

ptau.beacon()

Prepare for phase 2:

ptau.prep_phase2()

The PTau object maintains an underlying powers of tau file throughout these operations. You can also import an existing ptau file:

ptau = PTau(ptau_file="ptau_file.ptau")

At any stage, we can verify the powers of tau file is valid:

ptau.verify()

Circuit

Start by importing Circuit:

from zkpy.circuit import Circuit, PLONK

This class uses a circuit defined in a circom file to generate and verify zk proofs.

Here is an example scenario walking through compiling a circuit, generating witnesses, generating a proof, and verifying the proof: First, create the circuit object:

circuit = Circuit("./circuit.circom")

Compile the circuit:

circuit.compile()

Get info about the circuit and print constraints:

circuit.get_info()
circuit.print_constraints()

Generate witness from an input file:

circuit.gen_witness("./example_circuits/input.json")

Setup proof (this requires a previous powers of tau ceremony):

circuit.setup(PLONK, ptau)

Generate the proof:

circuit.prove(PLONK)

Export verification key:

circuit.export_vkey()

Verify proof:

circuit.verify(PLONK, vkey_file="vkey.json", public_file="public.json", proof_file="proof.json")

Contributing

Help is always appreciated! Feel free to open an issue if you find a problem, or open a pull request if you've solved an issue.

See more at CONTRIBUTING.md