Bip39 mnemonic C++ implementation. Contains java bindings.

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

• Generate random mnemonic (PCG generator)
• Create root and extended bip* standard keys using some derivation path

Supported distributions:

• centos 7, 8
• fedora 32-34

Steps:

• Create edwardstock.repo file inside /etc/yum.repos.d
• Add below to this file

[edwardstock]
name=edwardstock
baseurl=https://edwardstock.jfrog.io/artifactory/rhel/[centos or fedora]/\$releasever/\$basearch
enabled=1
gpgcheck=0
gpgkey=https://edwardstock.jfrog.io/artifactory/rhel/[centos or fedora]/\$releasever/\$basearch/repodata/repomd.xml.key
repo_gpgcheck=1

• Update repository yum -y update or dnf update
• Install lib yum install bip3x-devel

Supported distributions:

• debian: stretch, buster
• ubuntu: xenial, bionic, focal, groovy

echo "deb https://edwardstock.jfrog.io/artifactory/debian {distribution} main" | sudo tee -a /etc/apt/sources.list
curl -s https://edwardstock.jfrog.io/artifactory/api/gpg/key/public | sudo apt-key add -
apt update && apt install libbip3x-dev

After installing package from repository, you can use cmake-find module to find library:

find_package(bip3x 2.2.1 REQUIRED)
target_link_libraries(MY_PROJECT bip3x::bip39)

• Install cmake (if not installed yet)
• Install Oracle JDK or OpenJDK (not tested yet)
• Set environment variable: JAVA_HOME=/path/to/jdk
• Build

mkdir build && cd build
cmake ../ -DCMAKE_BUILD_TYPE=Release -DENABLE_SHARED=On -DENABLE_BIP39_JNI=On -DENABLE_BIP39_C=Off -DENABLE_TEST=Off

make -j 4

• Pickup lib files:
  • libbip39.[a | so | dylib]
  • libbip39_jni.[so | dylib]

• 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 -DUSE_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:
  • libbip39.dll
  • libbip39.dll.a
  • libbip39_jni.dll
  • libbip39_jni.dll.a

Requirements

• CMake for Windows
• Visual Studio (at least community edition), tested only version 2019
• Visual Studio C++ compiler
• To build tests, you could install Conan OR just set configure-time flag -DENABLE_CONAN=Off and resolve submodules: git submodule update --init --recursive

Step-by-step:

cmake .. -DCMAKE_BUILD_TYPE=Debug -DCMAKE_INSTALL_PREFIX="D:\path\you\want\to\install\libs"
cmake --build .
cmake --build . --target install

Then pick-up lib files and headers from D:\path\you\want\to\install\libs

#include <bip3x/utils.h>
#include <bip3x/Bip39Mnemonic.h>
#include <bip3x/HDKeyEncoder.h>
#include <iostream>

using namespace bip3x;

int main(int argc, char** argv) {
    // create random words
    Bip39Mnemonic::MnemonicResult encodedMnemonic = Bip39Mnemonic::generate();
    std::cout << encodedMnemonic.words << std::endl;
    
    // create mnemonic seed
    bytes_64 seed = HDKeyEncoder::makeBip39Seed(encodedMnemonic.words);
    
    // create root key from mnemonic seed
    HDKey bip32RootKey = HDKeyEncoder::makeBip32RootKey(seed);
    
    // and, finally derive keys
    // copy key to leave root key
    HDKey ethereumKey = bip32RootKey;
    // makeExtendedKey modifies source key
    HDKeyEncoder::makeExtendedKey(ethereumKey, "m/44'/60'/0'/0");

    // extended private key
    std::cout << ethereumKey.extPrivateKey.toString() << std::endl;
    
    // private key
    std::cout << ethereumKey.privateKey.toString() << std::endl;
    
    // extended public key
    std::cout << ethereumKey.extPublicKey.toString() << std::endl;
    
    // public key
    std::cout << ethereumKey.publicKey.toString() << std::endl;
    
    // et cetera..

    // the end.
    return 0;
}

tbd

• 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-bindings)
cmake_minimum_required(VERSION 3.4)
    
# 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.NativeBip39

class Main {
    public static int main(String[] args) {
        NativeBip39.init();
        
        if(!NativeBip39.isEnabled()) {
            throw new RuntimeException(NativeBip39.getError());
        }
    }
}

• Done!

• Just add it

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

and

target_link_libraries(bip39)

• Done!

TBD (see src/main.cpp for simple examples)