How Client-Side Encryption Works in Password Managers

Introduction

In the age of data breaches and digital surveillance, privacy is more important than ever—especially when it comes to your passwords. Many people are switching to zero-knowledge password managers, but few understand the mechanics behind them. In this post, we’ll break down exactly how client-side encryption works in password managers, and why it's essential for keeping your credentials safe.

What Is Client-Side Encryption?

Client-side encryption means that all encryption and decryption of your data happens on your device, before it is sent anywhere. The server stores only encrypted (unreadable) data—without access to your master password or encryption key.

🔒 How It Works:

• You enter a master password on your device.
• A cryptographic key is derived locally using algorithms like PBKDF2 or bcrypt.
• Your credentials are encrypted with this key using AES-256 encryption.
• The encrypted data (ciphertext) is then sent to the server for storage.

At no point is your master password or unencrypted data exposed to the server.

Why Is Client-Side Encryption Important?

Here are some of the key benefits:

• Zero-Knowledge Security: Even the password manager provider cannot see your data.
• Protection from Server Breaches: If a hacker accesses the database, they only see encrypted blobs.
• Full Control: Only you can decrypt the data—with your master password or recovery key.

This approach gives you peace of mind that your vault remains private, even in the worst-case scenarios.

How LitePassword Uses Client-Side Encryption

LitePassword follows a strict zero-knowledge model, meaning:

• Your Master Password is never sent to the server
• All sensitive data is encrypted on your device
• We store only encrypted blobs in our backend (Strapi + PostgreSQL)

You also get a Recovery Key at signup that allows you to restore access securely—again, without any server-side password resets or backdoors.

Technical Breakdown (For Developers)

Here’s a simplified version of the encryption process using JavaScript:

import CryptoJS from 'crypto-js';

const deriveEncryptionKey = (masterPassword, userId) => {
  return CryptoJS.PBKDF2(masterPassword, userId, {
    keySize: 256 / 32,
    iterations: 100000
  }).toString();
};

const encryptData = (plainText, encryptionKey) => {
  return CryptoJS.AES.encrypt(plainText, encryptionKey).toString();
};

const decryptData = (cipherText, encryptionKey) => {
  const bytes = CryptoJS.AES.decrypt(cipherText, encryptionKey);
  return bytes.toString(CryptoJS.enc.Utf8);
};

This keeps your encryption logic entirely on the client, fulfilling the zero-trust and zero-knowledge principles.

Final Thoughts

Understanding how client-side encryption works in password managers is crucial to choosing a tool you can trust. It’s not just a technical feature—it’s a foundation for your digital security. By encrypting everything before it reaches the cloud, password managers like LitePassword offer full privacy, true ownership, and peace of mind.