Generate group wallets offline using Python, Java or C++

In this article, we will explore three possible ways to generate bulk wallets (100,000 key pairs) offline in Python, Java, and C++. We will also look at using command line tools.

Method 1: Using OpenSSL

OpenSSL is a popular open source library used for cryptographic operations. We can use it to generate key pairs offline.

Python code

import subprocess
def generate_walletoffline():

Specify OpenSSL configuration file (e.g. openssl.conf)
config_file = "opensl.conf"

Specify wallet format (e.g. WHERE, WHERE)
wallet_format = "there"

Generate key pairs offline with 100,000 wallets
for i in range (100000):
command = f"openssl genrsa -out {config_file}_i{i}_{wallet_format}.der"
subprocess . run ( command , shell = True )

Extract private keys from generated wallets
wallet_dir = "wallets_{}_{wallet_format}".format(i + 1)
for filename in us.listdir(wallet_dir):
if filename.endwith(".there"):
s open ( os . path . join ( wallet_dir , filename ) , " rb " ) as f :

                key = f.read()

            private_key = key


            
Save the private key to a file (eg private_key_{}_{wallet_format}.pem.pyw)

            save_private_key(private_key)


if __name__ == "__main__":

    generate_walletoffline()

Java code

Java

import java.io.BufferedReader;

import java.io.File;

import java.io.FileWriter;

import java.io.IOException;

public class GenerateWalletOffline {

public static void main ( String [] args ) { ;

// Specify the OpenSSL configuration file (eg openssl.conf)

String configFile = "opensl.conf";

// Specify the wallet format (eg DER)

String walletFormat = "there";

// Generate key pairs offline with 100,000 wallets

for ( int i = 0 ; i < 100000 ; i ++ ) {

System.out.println("Generating private key " + (i + 1) + ...);

// Execute the OpenSSL command to generate the wallet

String command = "openssl genrsa -out " + configFile + "_i" + (i + 1) + "_" + walletFormat + ".der";

Process process = Runtime.getRuntime().exec(command);

BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));

String inputLine;

while ((inputLine = reader.readLine()) != null) {

// Extract the private key from the output

System.out.println("Private key " + (i + 1) + ... = " + inputLine);

} }

} }

// Save generated private keys to files (egprivate_key_100000_i0.derandprivate_key_100000_i0.pwpk`)

for ( int i = 0 ; i < 100000 ; i ++ ) {

System.out.println("Saving private key " + (i + 1) + ... to file");

// Execute the OpenSSL command to save the private key

String filename = configFile + "_" + (i + 1) + "_" + walletFormat + ".pwpk";

try ( FileWriter writer = new FileWriter ( filename )) { ;

writer.write("private_key_" + (i + 1) + ...);

} }

} }

} }

} }

C++ code

cpp

#include

#include

#include

#include

// Function to generate private key

std :: string generatePrivateKey ( size_t n , size_t p ) { ;

unsigned char * key = new unsigned char [ n + 1 ] ;

RAND_bytes ( key , n );

std :: stringstream ss ;

for (size_t i = 0; i < n; i++) {

ss << static_cast(key[i]) | 0x80;

} }

// Save the private key to a file

std::ofstream file("private_key_" + std::to_string(n) + "_" + std::to_string(p) + ".pwpk");

if ( file .