Encryption

What is Encryption?

Encryption is the process of converting plain text (readable data) into cipher text (scrambled data) using a specific algorithm and key. Only someone with the correct key can reverse the process and read the original message.

Example:

Imagine you want to send a secret note to your friend:

• Plain text: “Meet me at 3PM.”
• Encrypted (with Caesar cipher): “Phhw ph dw 3SP.”

Why is Encryption Important?

Encryption protects sensitive data from unauthorized access.

Here’s why it’s critical:

• Privacy — Keeps messages, emails, and documents confidential. It ensures that only the intended recipient can read the contents, even if someone intercepts the data in transit.
• Security — Protects financial transactions and passwords. Encryption safeguards sensitive data such as credit card numbers, login credentials, and health records from being accessed or misused by attackers.
• Integrity — Prevents data tampering. Encryption ensures that the data hasn’t been altered during transmission, preserving its original state.
• Compliance — Meets regulatory requirements (like GDPR, HIPAA). Many industries are legally required to implement encryption to protect consumer data and avoid heavy fines.

Types of Encryption

Symmetric Encryption

• Uses one key to encrypt and decrypt.
• Fast and efficient for large amounts of data.
• Example algorithm: AES (Advanced Encryption Standard)

const crypto = require('crypto');
const key = crypto.randomBytes(32);
const iv = crypto.randomBytes(16);
 
const cipher = crypto.createCipheriv('aes-256-cbc', key, iv);
let encrypted = cipher.update('Hello world', 'utf8', 'hex');
encrypted += cipher.final('hex');

Asymmetric Encryption

• Uses a pair of keys: public (to encrypt) and private (to decrypt).
• Common in HTTPS, email encryption.
• Example algorithm: RSA

const { generateKeyPairSync, publicEncrypt, privateDecrypt } = require('crypto');
const { publicKey, privateKey } = generateKeyPairSync('rsa', {
  modulusLength: 2048,
});
 
const data = Buffer.from("Secret");
const encrypted = publicEncrypt(publicKey, data);
const decrypted = privateDecrypt(privateKey, encrypted);

Where Encryption is Used

• Messaging apps (e.g. WhatsApp, Signal)
• Websites (HTTPS)
• Password storage (bcrypt, scrypt)
• Online banking
• VPN and secure browsing

Common Encryption Algorithms

Hashing vs. Encryption

Hashing is one-way and irreversible. Encryption is two-way.

Conclusion

Encryption is all around us — from securing your bank app to protecting chats with your friends. Understanding the basics of how it works is essential in today’s digital age.

Stay secure, and remember: if it’s not encrypted, it’s not private.

References

How HTTPS Works

The Caesar Cipher Explained