Cryptography forms the backbone of modern cybersecurity — enabling secure communication, privacy, and digital trust. This module introduces essential encryption methods and breaks down how they work in practice.
🔐 Symmetric Key Encryption
Symmetric encryption uses a single key for both encryption and decryption. It’s fast and widely used for protecting files and data in transit.
- 🔒 AES (Advanced Encryption Standard)
- 🔒 DES (Data Encryption Standard)
- 💽 BitLocker (full disk encryption on Windows)
🔑 Asymmetric Public Key Encryption
Asymmetric encryption uses two keys — a public key to encrypt and a private key to decrypt. It underpins secure internet protocols and digital identity.
- 🧮 RSA (used for digital signatures and encryption)
- 📡 Diffie-Hellman (secure key exchange)
- 🔐 ElGamal (used in hybrid encryption systems)
- 🌐 HTTPS (powered by SSL/TLS protocols)
📊 Symmetric vs Asymmetric: Key Differences
- Symmetric: Much faster, best for bulk data — but requires secure key sharing.
- Asymmetric: More secure for open communication — but computationally slower.
🔄 Caesar Cipher (ROT13 Demo)
The Caesar Cipher is a classic encryption technique. Each letter is shifted by a fixed amount — for example, ROT13 shifts letters by 13 positions.
Encrypted: ubcrlbherawblvatguvfoybtcbfg
Decrypted (ROT13): hopeyourenjoyingthisblogpost
💡 Tip: Try creating your own Caesar Cipher encoder/decoder as a coding challenge!
Pro Insight: Most secure websites today use asymmetric encryption to exchange keys, then switch to symmetric encryption for faster data transfer.
