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gnark is a fast zk-SNARK library that offers a high-level API to design circuits. The library is open source and developed under the Apache 2.0 license

Home Page: https://hackmd.io/@gnark

License: Apache License 2.0

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gnark's Introduction

`gnark` zk-SNARK library

gnark is a fast zk-SNARK library that offers a high-level API to design circuits. The library is open source and developed under the Apache 2.0 license

Useful Links

gnark User Documentation
gnark Playground
gnark Issues
gnark Benchmarks 🏁
gnark-announce - Announcement list for new releases and security patches

`gnark` Users

To get started with gnark and write your first circuit, follow these instructions.

Checkout the online playground to compile circuits and visualize constraint systems.

Warning

gnark has been partially audited and is provided as-is, we make no guarantees or warranties to its safety and reliability. In particular, gnark makes no security guarantees such as constant time implementation or side-channel attack resistance.

gnark and gnark-crypto packages are optimized for 64bits architectures (x86 amd64) and tested on Unix (Linux / macOS).

Issues

gnark issues are tracked in the GitHub issues tab.

To report a security bug, please refer to gnark Security Policy.

If you have any questions, queries or comments, GitHub discussions is the place to find us.

You can also get in touch directly: [email protected]

Release Notes

Proving schemes and curves

Refer to Proving schemes and curves for more details.

gnark support the following zk-SNARKs:

which can be instantiated with the following curves

Example

Refer to the gnark User Documentation

Here is what x**3 + x + 5 = y looks like

package main

import (
	"github.com/consensys/gnark-crypto/ecc"
	"github.com/consensys/gnark/backend/groth16"
	"github.com/consensys/gnark/frontend"
	"github.com/consensys/gnark/frontend/cs/r1cs"
)

// CubicCircuit defines a simple circuit
// x**3 + x + 5 == y
type CubicCircuit struct {
	// struct tags on a variable is optional
	// default uses variable name and secret visibility.
	X frontend.Variable `gnark:"x"`
	Y frontend.Variable `gnark:",public"`
}

// Define declares the circuit constraints
// x**3 + x + 5 == y
func (circuit *CubicCircuit) Define(api frontend.API) error {
	x3 := api.Mul(circuit.X, circuit.X, circuit.X)
	api.AssertIsEqual(circuit.Y, api.Add(x3, circuit.X, 5))
	return nil
}

func main() {
	// compiles our circuit into a R1CS
	var circuit CubicCircuit
	ccs, _ := frontend.Compile(ecc.BN254.ScalarField(), r1cs.NewBuilder, &circuit)

	// groth16 zkSNARK: Setup
	pk, vk, _ := groth16.Setup(ccs)

	// witness definition
	assignment := CubicCircuit{X: 3, Y: 35}
	witness, _ := frontend.NewWitness(&assignment, ecc.BN254.ScalarField())
	publicWitness, _ := witness.Public()

	// groth16: Prove & Verify
	proof, _ := groth16.Prove(ccs, pk, witness)
	groth16.Verify(proof, vk, publicWitness)
}

GPU Support

Icicle Library

The following schemes and curves support experimental use of Ingomyama's Icicle GPU library for low level zk-SNARK primitives such as MSM, NTT, and polynomial operations:

Groth16

instantiated with the following curve(s)

BN254

To use GPUs, add the icicle buildtag to your build/run commands, e.g. go run -tags=icicle main.go.

You can then toggle on or off icicle acceleration by providing the WithIcicleAcceleration backend ProverOption:

    // toggle on
    proofIci, err := groth16.Prove(ccs, pk, secretWitness, backend.WithIcicleAcceleration())
    
    // toggle off
    proof, err := groth16.Prove(ccs, pk, secretWitness)

For more information about prerequisites see the Icicle repo.

Citing

If you use gnark in your research a citation would be appreciated. Please use the following BibTeX to cite the most recent release.

@software{gnark-v0.9.0,
  author       = {Gautam Botrel and
                  Thomas Piellard and
                  Youssef El Housni and
                  Ivo Kubjas and
                  Arya Tabaie},
  title        = {ConsenSys/gnark: v0.9.0},
  month        = feb,
  year         = 2023,
  publisher    = {Zenodo},
  version      = {v0.9.0},
  doi          = {10.5281/zenodo.5819104},
  url          = {https://doi.org/10.5281/zenodo.5819104}
}