How to Effectively Use BCrypt for Password Hashing in Java

What are the best practices for using BCrypt for password hashing in Java?

import org.mindrot.jbcrypt.BCrypt;

public class PasswordUtil {
    // Method to hash a password using BCrypt
    public static String hashPassword(String plainPassword) {
        return BCrypt.hashpw(plainPassword, BCrypt.gensalt());
    }

    // Method to verify a password against a stored hash
    public static boolean verifyPassword(String plainPassword, String hashedPassword) {
        return BCrypt.checkpw(plainPassword, hashedPassword);
    }
}

BCrypt is a robust hashing function that provides secure password storage by utilizing a salt to protect against rainbow table attacks and is inherently resistant to brute-force attacks. When integrating BCrypt in Java, following best practices enhances security and effectiveness.

String plainPassword = "securePassword123";
String hashedPassword = PasswordUtil.hashPassword(plainPassword);
if (PasswordUtil.verifyPassword(plainPassword, hashedPassword)) {
    System.out.println("Password is valid.");
} else {
    System.out.println("Invalid password.");
}

Causes

• Not using a unique salt for each password hash.
• Using BCrypt for non-password storage (e.g., general data).
• Failing to update hash factors when computational power increases.

Solutions

• Always use BCrypt's built-in salt generation: BCrypt.gensalt().
• Use BCrypt for passwords only, not for other data types.
• Adjust the work factor regularly to maintain security over time.

Mistake: Directly storing plain passwords in the database

Solution: Always hash passwords before storing them using BCrypt.

Mistake: Using a fixed salt instead of a unique one for each password

Solution: Utilize BCrypt's gensalt method to automatically generate a unique salt.