# libzkg

**Repository Path**: FISCO-BCOS/libzkg

## Basic Information

- **Project Name**: libzkg
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: MIT
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2019-05-22
- **Last Updated**: 2024-06-08

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# Libzkg Development Guide

FISCO-BCOS use libzkg to generate zero-knowledge proof for user and only governer can oversee it!

Notice: This is an experimental prototype. Do not use it in product.

## Introductions

### Background

Security is a basic deveping purpose of FISCO-BCOS.

- For users, they need sheild transactions and anyone else couldn't know their transaction information running on blockchain.
- For verifiers(FISCO-BCOS nodes), they need to verify all sheild transacitons, without knowing something of the shield transactions.
- For goverments, they need to oversee everything happen on blockchain even the shield transactions!

### Ideas

Libzkg is a zero-knowledge proof library based on FISCO-BCOS project.-  

- For users, they use libzkg to generate shield transactions, nobody else can know what's inside the transactions.
- For verifiers, they can verify every shield transactions generated by libzkg without knowing something of the transactions.
- For goverments, they can decode the shield transactions on blockchain and know what's happend.

### Design

Libzkg is deveped for supporting zero-knowldge proof senarios of FISCO-BCOS.

Every senario supported by libzkg is based on this 3 principle:

- User can generate a shield transaction according with the certain senario.
- Verifier can verify the shield transaction without knowing the information of the transaction.
- Goverment can decode every shield transaction on blockchain.

### Supporting Senarios

- Tx1to1: Shield money transfer from one to one.
- Anonymous donation(developing)

waiting for more..



## Compile Option

To import libzkg in your project. Cmake is recommended.

**Prepare**

``` shell
sudo yum install -y procps-ng procps-ng-devel libgomp
```

**Download**

> Download cmake file

``` shell
wget https://github.com/FISCO-BCOS/FISCO-BCOS/blob/master/cmake/ProjectLibZkg.cmake
cp ProjectLibZkg.cmake your_project_dir/cmake/
```

**CMakeLists.txt**

> Import in your CMakeLists.txt

``` shell
vim  your_project_dir/CMakeLists.txt
```

> like

``` cmake
cmake_minimum_required (VERSION 3.0.0)

set(ZKG_CLIENT_CMAKE_DIR "${CMAKE_CURRENT_LIST_DIR}/cmake" CACHE PATH "The path to the cmake directory")
list(APPEND CMAKE_MODULE_PATH ${ZKG_CLIENT_CMAKE_DIR})

include(ProjectLibZkg)

find_package(OpenMP)
if(OPENMP_FOUND)
    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${OpenMP_C_FLAGS}")
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${OpenMP_EXE_LINKER_FLAGS}")
endif()

include_directories(${LIBZKG_INCLUDE_DIR})

add_compile_options(-DMULTICORE)
add_compile_options(-std=c++11)
add_compile_options(-DCURVE_ALT_BN128)
add_compile_options(-DNO_PROCPS)
add_compile_options(-DBINARY_OUTPUT=OFF)

#aux_source_directory(. DIR_SRCS)

set(DEMO "demo")
add_executable(${DEMO} demo.cpp)

target_link_libraries(${DEMO} Zkg)
target_link_libraries(${DEMO} Zkg::circuit)
target_link_libraries(${DEMO} Zkg::snark)
target_link_libraries(${DEMO} Zkg::ff)
target_link_libraries(${DEMO} Zkg::zm)
target_link_libraries(${DEMO} gmp)
target_link_libraries(${DEMO} stdc++)
target_link_libraries(${DEMO} procps)
target_link_libraries(${DEMO} gmpxx)
target_link_libraries(${DEMO} gomp)

```

**cpp files**

>  Include zkg.hpp in your cpp file

``` cpp
#include <circuit/zkg.hpp>
```

**Compile**

``` shell
mkdir build
cd build
cmake3 ..
make
#If success, libzkg.a is generated
```

 

## Senario 1: tx1to1 

consult with [zkg.hpp](circuit/zkg.hpp) and [zkg-tx1to1](https://github.com/FISCO-BCOS/zkg-tx1to1)