Important note

This is a new implementation of rapidsnark. The original (and now obsoleted) implementation is available here: rapidsnark-old.

rapidsnark

Rapidsnark is a fast zkSnark proof generator written in C++ and Intel/ARM assembly. It generates proofs for circuits created with circom and snarkjs.

Dependencies

Install gcc, cmake, libsodium, and gmp (development libraries).

On Ubuntu:

sudo apt-get install build-essential cmake libgmp-dev libsodium-dev nasm curl m4

On MacOS:

brew install cmake gmp libsodium nasm

Compile prover in standalone mode

Compile prover for x86_64 host machine

git submodule update --init --recursive
./build_gmp.sh host
make host

Compile prover for macOS arm64 host machine

git submodule update --init --recursive
./build_gmp.sh macos_arm64
make macos_arm64

Compile prover for linux arm64 machine

git submodule update --init --recursive
./build_gmp.sh aarch64
make host_arm64

Compile prover for Android

Install Android NDK from https://developer.android.com/ndk or using the SDK Manager in Android Studio.

Set the value of ANDROID_NDK environment variable to the absolute path of Android NDK root directory.

Examples:

export ANDROID_NDK=/home/test/Android/Sdk/ndk/23.1.7779620  # NDK is installed by "SDK Manager" in Android Studio.
export ANDROID_NDK=/home/test/android-ndk-r23b              # NDK is installed as a stand-alone package.

Prerequisites for building on Ubuntu:

apt-get install curl xz-utils build-essential cmake m4 nasm

Compilation:

git submodule update --init --recursive
./build_gmp.sh android
make android

Compile prover for iOS

Install Xcode.

git submodule update --init --recursive
./build_gmp.sh ios
make ios

Open the generated Xcode project and compile the prover.

Build for iOS emulator

Install Xcode.

git submodule update --init --recursive
./build_gmp.sh ios_simulator
make ios_simulator

Files that you need to copy to your XCode project to link against Rapidsnark:

• build_prover_ios_simulator/src/Debug-iphonesimulator/librapidsnark.a
• build_prover_ios_simulator/src/Debug-iphonesimulator/libfq.a
• build_prover_ios_simulator/src/Debug-iphonesimulator/libfr.a
• depends/gmp/package_iphone_simulator/lib/libgmp.a

Building proof

After compilation, the prover is available in the build directory.

You can replace the snarkjs command:

snarkjs groth16 prove <circuit.zkey> <witness.wtns> <proof.json> <public.json>

with:

./package/bin/prover <circuit.zkey> <witness.wtns> <proof.json> <public.json>

Compile prover in server mode

npm install
git submodule update --init --recursive
npx task buildPistache
npx task buildProverServer

Launch prover in server mode

./build/proverServer  <port> <circuit1_zkey> <circuit2_zkey> ... <circuitN_zkey>

For each circuit, compile it with circom --c to generate the C++ witness generator. Copy the compiled executable to the build folder so the server can generate witnesses and proofs.

See /tools/request.js for an example of calling the server endpoints with Node.js.

To test a request, pass an input.json as a parameter:

node tools/request.js <input.json> <circuit>

Wrappers

Rapidsnark can be used with several programming languages and environments through wrappers that provide integration with the original library. Below is a list of available wrappers:

Wrapper	Repository Link
Go	https://github.com/iden3/go-rapidsnark
iOS	https://github.com/iden3/ios-rapidsnark
Android	https://github.com/iden3/android-rapidsnark
React Native	https://github.com/iden3/react-native-rapidsnark
Flutter	https://github.com/iden3/flutter-rapidsnark

Benchmark

The prover parallelizes proof generation as much as possible.

The prover is much faster than snarkjs and faster than bellman.

[TODO] Some comparative tests should be done.

Run tests

You need to perform all the steps from the Compile prover in standalone mode section. After that you can run tests with the following command from the build directory:

# Make sure you are in the build directory
# ./build_prover for linux, ./build_prover_macos_arm64 for macOS.
cmake --build . --parallel && ctest --rerun-failed --output-on-failure

To run just the test_public_size test for custom zkey to measure the performance, you can run the following command from the build directory:

src/test_public_size ../testdata/circuit_final.zkey 86

License

rapidsnark is part of the iden3 project copyright 2021 0KIMS association and published with LGPL-3 license. Please check the COPYING file for more details.