Core Cryptographic Concepts

Concept

How It Works

Real-World Use

Symmetric

Same key encrypts & decrypts (AES, DES)

File encryption, VPN tunnels

Asymmetric

Public key encrypts, private key decrypts (RSA)

HTTPS, email signing, SSH

Hashing

One-way transformation (MD5, SHA256)

Password storage, file integrity

Digital Sig

Proves authenticity using private key

Code signing, document verification

SSL/TLS

Encrypts communication over internet

HTTPS websites, secure APIs

 

📌 Placement Tip: Be able to explain the difference between encoding, encryption, and hashing. Encoding (Base64) is reversible without a key. Encryption requires a key. Hashing is one-way and irreversible.

 

Common Attack Against Cryptography

  • Brute Force Attack — Trying all possible keys or passwords
  • Dictionary Attack — Using a wordlist to crack password hashes
  • Rainbow Table Attack — Pre-computed hash table for fast cracking
  • Man-in-the-Middle — Intercepting communication to decrypt/re-encrypt
PreviousNext