Week 7 Final Project: Password Manager

Managing passwords effectively in today's digital landscape is crucial for securing your online identity and sensitive information. A robust password manager can be your best defense against cyber threats, helping you generate, store, and manage strong, unique passwords for all your accounts. This article delves into the intricacies of creating a password manager as a final project, covering everything from the initial design considerations to the implementation and security aspects.

Why Build Your Own Password Manager?

While numerous commercial password managers exist, building your own provides several advantages:

• Customization: Tailor the application to your specific needs and preferences.
• Control: Gain complete control over your data and how it's stored.
• Learning Experience: Develop valuable skills in software development, security, and cryptography.
• Cost Savings: Avoid subscription fees associated with commercial products.
• Security Audit: Implement security measures that you understand and trust.

Project Scope and Requirements

Before diving into the code, define the scope of your password manager project. Consider these essential features:

• Password Generation: Generate strong, random passwords based on user-defined criteria (length, character types).
• Password Storage: Securely store passwords using encryption.
• Password Retrieval: Easily retrieve stored passwords.
• User Authentication: Protect access to the password manager itself.
• User Interface (UI): Create a user-friendly interface for managing passwords.
• Search Functionality: Allow users to quickly search for specific passwords.
• Password Organization: Enable users to categorize and organize their passwords.

Optional but beneficial features include:

• Auto-fill: Automatically fill in passwords on websites and applications.
• Password Strength Meter: Evaluate the strength of existing and generated passwords.
• Two-Factor Authentication (2FA): Add an extra layer of security to user authentication.
• Password History: Track password changes over time.
• Cross-Platform Compatibility: Support multiple operating systems (Windows, macOS, Linux) and devices (desktop, mobile).

Technology Stack

Choosing the right technology stack is crucial for the success of your password manager project. Here are some popular options:

• Programming Languages:
  • Python: Known for its simplicity, readability, and extensive libraries, making it ideal for rapid development.
  • Java: Offers platform independence and strong security features, suitable for enterprise-grade applications.
  • C#: A powerful language for developing Windows applications with robust security capabilities.
  • JavaScript: Primarily used for web-based password managers, offering cross-platform compatibility.
• Databases:
  • SQLite: A lightweight, file-based database perfect for storing encrypted password data locally.
  • MySQL: A robust, open-source database suitable for larger-scale applications with multiple users.
  • PostgreSQL: Another powerful, open-source database known for its reliability and advanced features.
• Encryption Libraries:
  • Cryptography (Python): Provides cryptographic primitives for secure encryption and decryption.
  • Bouncy Castle (Java, C#): A widely used cryptographic library with a comprehensive set of algorithms and protocols.
  • Libsodium: A modern, easy-to-use cryptographic library focusing on security and performance.
• UI Frameworks:
  • Tkinter (Python): A simple, cross-platform GUI toolkit for creating basic desktop applications.
  • PyQt (Python): A more advanced GUI framework with a rich set of widgets and features.
  • JavaFX (Java): A modern UI toolkit for building rich client applications in Java.
  • .NET Framework (C#): Provides a comprehensive set of tools and libraries for developing Windows applications with graphical user interfaces.
  • React, Angular, Vue.js (JavaScript): Popular JavaScript frameworks for building dynamic web applications with user-friendly interfaces.

Implementation Steps

Here's a step-by-step guide to building your password manager:

1. Project Setup

• Choose your technology stack: Select the programming language, database, and UI framework that best suit your needs and skills.
• Set up your development environment: Install the necessary software and libraries.
• Create a new project: Initialize a new project in your chosen IDE or editor.

2. User Authentication

• Implement a secure login system: Allow users to create accounts and log in using a username and password.
• Hash passwords: Store user passwords as salted hashes instead of plain text to protect against unauthorized access. Use strong hashing algorithms like Argon2, bcrypt, or scrypt.
• Consider two-factor authentication: Add an extra layer of security by requiring users to enter a code from their mobile device in addition to their password.

3. Password Generation

• Create a password generator function: Generate strong, random passwords based on user-defined criteria.
• Allow customization: Let users specify the length of the password and the types of characters to include (uppercase letters, lowercase letters, numbers, symbols).
• Use a cryptographically secure random number generator: Ensure that the generated passwords are truly random and unpredictable.

4. Password Storage

• Choose an encryption algorithm: Select a strong encryption algorithm like AES (Advanced Encryption Standard) or ChaCha20 to encrypt passwords before storing them in the database.
• Generate a unique encryption key: Create a unique encryption key for each user to further protect their data. Store this key securely, preferably using a key derivation function (KDF) like PBKDF2 or Argon2 to derive it from the user's master password.
• Encrypt passwords: Encrypt each password using the encryption key before storing it in the database.
• Store encrypted data: Store the encrypted passwords, usernames, and website URLs in the database.

5. Password Retrieval

• Decrypt passwords: When a user requests a password, decrypt it using the encryption key.
• Display decrypted password: Display the decrypted password to the user.
• Implement copy-to-clipboard functionality: Allow users to easily copy the decrypted password to their clipboard.

6. User Interface

• Design a user-friendly interface: Create a simple, intuitive interface for managing passwords.
• Implement password listing: Display a list of stored passwords, organized by website or category.
• Add, edit, and delete passwords: Allow users to add new passwords, edit existing passwords, and delete passwords.
• Implement search functionality: Enable users to quickly search for specific passwords.

7. Security Considerations

• Protect against brute-force attacks: Implement rate limiting and account lockout mechanisms to prevent attackers from guessing user passwords.
• Secure the encryption key: Protect the encryption key used to encrypt and decrypt passwords. Store it securely and never expose it to unauthorized users.
• Regularly update dependencies: Keep your software and libraries up to date to patch security vulnerabilities.
• Conduct security audits: Regularly audit your code for potential security flaws.
• Implement input validation: Validate all user input to prevent injection attacks.
• Use secure coding practices: Follow secure coding practices to minimize the risk of security vulnerabilities.

Code Examples (Python with SQLite and Cryptography)

Here are some code snippets to illustrate key aspects of the password manager implementation using Python, SQLite, and the Cryptography library.

1. Password Generation:

import secrets
import string

def generate_password(length=16):
    """Generates a strong, random password."""
    alphabet = string.ascii_letters + string.digits + string.punctuation
    password = ''.join(secrets.choice(alphabet) for i in range(length))
    return password

# Example usage
new_password = generate_password(20)
print(f"Generated password: {new_password}")

2. Password Hashing (Argon2):

import bcrypt

def hash_password(password):
    """Hashes a password using bcrypt."""
    # Generate a salt
    salt = bcrypt.gensalt()

    # Hash the password with the salt
    hashed_password = bcrypt.hashpw(password.encode('utf-8'), salt)

    return hashed_password.decode('utf-8')

def verify_password(password, hashed_password):
    """Verifies a password against a hash."""
    return bcrypt.checkpw(password.encode('utf-8'), hashed_password.encode('utf-8'))

# Example usage
password = "mysecretpassword"
hashed = hash_password(password)
print(f"Hashed password: {hashed}")

# Verify the password
is_valid = verify_password(password, hashed)
print(f"Password is valid: {is_valid}")

3. Encryption and Decryption (AES):

from cryptography.fernet import Fernet
import base64

def generate_key():
    """Generates a Fernet encryption key."""
    return Fernet.generate_key()

def encrypt_password(password, key):
    """Encrypts a password using Fernet."""
    f = Fernet(key)
    encrypted_password = f.encrypt(password.encode('utf-8'))
    return encrypted_password

def decrypt_password(encrypted_password, key):
    """Decrypts a password using Fernet."""
    f = Fernet(key)
    decrypted_password = f.decrypt(encrypted_password).decode('utf-8')
    return decrypted_password

# Example usage
key = generate_key()
print(f"Encryption key: {key.decode()}")
password = "mysecretpassword"
encrypted = encrypt_password(password, key)
print(f"Encrypted password: {encrypted}")

decrypted = decrypt_password(encrypted, key)
print(f"Decrypted password: {decrypted}")

4. SQLite Database Interaction:

import sqlite3

def create_table():
    """Creates the passwords table in the database."""
    conn = sqlite3.connect('passwords.db')
    cursor = conn.cursor()
    cursor.execute('''
        CREATE TABLE IF NOT EXISTS passwords (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            website TEXT NOT NULL,
            username TEXT NOT NULL,
            password TEXT NOT NULL,
            key TEXT NOT NULL
        )
    ''')
    conn.commit()
    conn.close()

def add_password(website, username, password, key):
    """Adds a password to the database."""
    conn = sqlite3.connect('passwords.db')
    cursor = conn.cursor()
    cursor.execute('INSERT INTO passwords (website, username, password, key) VALUES (?, ?, ?, ?)',
                   (website, username, password, key.decode()))
    conn.commit()
    conn.close()

def get_password(website):
    """Retrieves a password from the database."""
    conn = sqlite3.connect('passwords.db')
    cursor = conn.cursor()
    cursor.execute('SELECT password, key FROM passwords WHERE website = ?', (website,))
    result = cursor.fetchone()
    conn.close()
    if result:
        return result[0], result[1].encode()  # Password and key
    return None, None

# Example usage
create_table()
key = generate_key()
password = "mysecretpassword"
encrypted = encrypt_password(password, key)
add_password("example.com", "user123", encrypted, key)

retrieved_password, retrieved_key = get_password("example.com")
if retrieved_password:
    decrypted = decrypt_password(retrieved_password, retrieved_key)
    print(f"Retrieved password: {decrypted}")
else:
    print("Password not found.")

Note: These code snippets are simplified examples and may require further refinement for a production-ready password manager.

Advanced Features and Enhancements

Consider implementing these advanced features to enhance your password manager:

• Auto-fill functionality: Automatically fill in passwords on websites using browser extensions or accessibility APIs.
• Password strength meter: Provide feedback on the strength of user-created passwords.
• Password history: Track password changes over time, allowing users to revert to previous passwords if necessary.
• Cloud synchronization: Sync passwords across multiple devices using a secure cloud storage service.
• Password sharing: Allow users to securely share passwords with trusted contacts.
• Integration with password breach databases: Check stored passwords against known data breaches to identify compromised accounts.
• Mobile app development: Create a mobile app version of your password manager for iOS and Android.

Testing and Debugging

Thoroughly test your password manager to ensure its functionality and security.

• Unit testing: Write unit tests to verify the correctness of individual functions and modules.
• Integration testing: Test the interaction between different components of the application.
• Security testing: Conduct penetration testing and vulnerability assessments to identify security flaws.
• User acceptance testing: Get feedback from users to identify usability issues and areas for improvement.
• Debug rigorously: Use debugging tools to identify and fix errors in your code.

Security Best Practices

Security should be your top priority when building a password manager. Follow these best practices:

• Use strong encryption algorithms: Choose well-established and widely vetted encryption algorithms like AES or ChaCha20.
• Implement proper key management: Securely generate, store, and manage encryption keys. Use key derivation functions (KDFs) like PBKDF2 or Argon2 to derive keys from user passwords.
• Protect against brute-force attacks: Implement rate limiting and account lockout mechanisms to prevent attackers from guessing user passwords.
• Store passwords as salted hashes: Never store passwords in plain text. Use strong hashing algorithms like Argon2, bcrypt, or scrypt to hash passwords with a unique salt.
• Regularly update dependencies: Keep your software and libraries up to date to patch security vulnerabilities.
• Conduct security audits: Regularly audit your code for potential security flaws.
• Implement input validation: Validate all user input to prevent injection attacks.
• Use secure coding practices: Follow secure coding practices to minimize the risk of security vulnerabilities.

Conclusion

Building a password manager is a challenging but rewarding project that can significantly enhance your understanding of software development, security, and cryptography. By following the steps outlined in this article and adhering to security best practices, you can create a robust and secure password manager that meets your specific needs and provides a valuable learning experience. Remember to prioritize security throughout the development process and regularly test your application to identify and fix potential vulnerabilities. Good luck!