rapidsnark

---

This library is Android Kotlin wrapper for the Rapidsnark. It enables the generation of proofs for specified circuits within an Android environment.

Platform Support

Android: Compatible with any Android device with 64 bit architecture.

Requirements

• Android 7.0 (API level 24) or higher.

Installation

// TODO: Add instructions for installation

Usage

groth16Prove

Function takes path to .zkey file and witness file (as base64 encoded String) and returns proof and public signals.

Reads .zkey file directly from filesystem.

import io.iden3.rapidsnark.*

// ...

val wtns: ByteArray = readFile("path/to/wtns")

val (proof, publicSignals) = groth16Prove("path/to/zkey", wtns)

groth16Verify

Verifies proof and public signals against verification key.

import io.iden3.rapidsnark.*

// ...

val zkey: ByteArray = readFile("path/to/zkey")
val wtns: ByteArray = readFile("path/to/zkey")
val verificationKey: ByteArray = readFile("path/to/zkey")

val (proof, publicSignals) = groth16Prove(zkey, wtns)

val proofValid = groth16Verify(proof, publicSignals, verificationKey)

groth16PublicBufferSize

Calculates public buffer size for specified zkey.

import io.iden3.rapidsnark.*

// ...

val publicBufferSize = groth16PublicBufferSize("path/to/zkey")

Public buffer size

groth16Prove has an optional proofBufferSize, publicBufferSize and errorBufferSize parameters. If publicBufferSize is too small it will be calculated automatically by library.

These parameters are used to set the size of the buffers used to store the proof, public signals and error.

If you have embedded circuit in the app, it is recommended to calculate the size of the public buffer once and reuse it. To calculate the size of public buffer call groth16PublicBufferSize.

Example

To run the example project, clone the repo, and run app module application.

License

The project is licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE)
• MIT license (LICENSE-MIT)

at your option.

• Rapidsnark is licensed under the LGPL-3