Generate Random One Time Password(OTP) using Java

October 08, 2023

import java.util.Random;

public class OtpGenerator {

public static String generateRandomOtp(int length) {
        // Define the characters that can be used in the OTP
        String validChars = "0123456789"; // You can add more characters if needed

// Initialize a random number generator
        Random random = new Random();

// Create a StringBuilder to build the OTP
        StringBuilder otpBuilder = new StringBuilder(length);

// Generate random characters for the OTP
        for (int i = 0; i < length; i++) {
            int randomIndex = random.nextInt(validChars.length());
            char randomChar = validChars.charAt(randomIndex);
            otpBuilder.append(randomChar);
        }

// Convert the StringBuilder to a String and return the OTP
        return otpBuilder.toString();
    }

public static void main(String[] args) {
        int otpLength = 6; // You can specify the desired OTP length
        String randomOtp = generateRandomOtp(otpLength);
        System.out.println("Generated OTP: " + randomOtp);
    }
}