bip3x (with java bindings)

Bip39 mnemonic C++ implementation. Contains java bindings.

Description

Logic almost completely taken from bitcoin-js library for generating mnemonic phrases. Site and github

Features

• Generate random mnemonic (PCG generator)
• Create root and extended bip* standard keys using derivation path
• Get ETH-like address from private key (requires exactly private key, because it requires to get uncompressed public key)
• Simple message signing with private key (verify method is not implemented yet)

Build native JNI libs

• Install cmake (if not installed yet)
• Install Oracle JDK or OpenJDK (not tested yet)
• Set environment variable: JAVA_HOME=/path/to/jdk OR cmake prefix path like this: -DCMAKE_PREFIX_PATH="/Users/JohnDoe/.sdkman/candidates/java/17.0.6-amzn"
• Build

mkdir build && cd build
cmake ../ -DCMAKE_BUILD_TYPE=Release -Dbip3x_BUILD_SHARED_LIBS=On -Dbip3x_BUILD_JNI_BINDINGS=On -Dbip3x_BUILD_C_BINDINGS=Off -Dbip3x_BUILD_TESTS=Off

make -j 4

• Pickup lib files:
  • libbip3x.[a | so | dylib]
  • libbip3x_jni.[so | dylib]

Cross-compile for Windows under mingw64

• Setup mingw64 for linux or macOS
• Setup Windows JDK (or just copy from windows machine to somewhere path)
• IMPORTANT: using c++ (mt19937, and PCGRand not works properly too) random generator is not secure. Use -Dbip3x_USE_OPENSSL_RANDOM=On while configuring to use OpenSSL random generator.
• Build

mkdir build && cd build
cmake ../ -DCMAKE_BUILD_TYPE=Release \
-DCMAKE_TOOLCHAIN_FILE=../cmake/mingw-w64.cmake \
-DCMAKE_SYSROOT=/path/to/mingw \
-DCROSS_ARCH=[choose i686 or x86_64] \
-DJAVA_HOME=/path/to/extracted/windows/jdk

make

• Pickup lib files:
  • libbip3x.dll
  • libbip3x.dll.a
  • libbip3x_jni.dll
  • libbip3x_jni.dll.a

Examples

see exmaple.cpp file

Java

tbd

Android and java bindings (todo: separate android library with included java bindings)

• Add this project as submodule (or just copy as sources) to your android module:

cd /path/to/project/app/src/main
mkdir cpp && cd cpp
git submodule add https://github.com/edwardstock/bip3x.git bip39

• Create root cmake project in /path/to/project/[moduleName]/src/main/cpp

project(moduleName-cbip3x)
cmake_minimum_required(VERSION 3.24)
    
# include bip39
include_directories(bip39)
    
# add library
add_subdirectory(bip39)

• Configure gradle

android {
    ...
    sourceSets {
        main {
            jni.srcDirs = ['src/main/cpp/bip39/src/java']
            java.srcDirs = ['src/main/cpp/bip39/src/java']
        }
    }
    
    externalNativeBuild {
        cmake {
            path 'src/main/cpp/CMakeLists.txt'
        }
    }
    ...
}

• Initialize it

import com.edwardstock.bip3x.BIP3X

class Main {
    public static int main(String[] args) {
        BIP3X.init();

        if (!BIP3X.isEnabled()) {
            throw new RuntimeException(BIP3X.getError());
        }
    }
}

• Done!

Add to CMake project

• Just add it

# include bip39
include_directories(bip39)
    
# add library
add_subdirectory(bip39)

and

target_link_libraries(bip39)

• Done!