Cyber Security Online Course - Principles (CIA), Cryptograpy ( Encryption, Encoding , Hashing)

Principles: CIA Confidentiality: Protect information from unauthorized access. Integrity: Ensure information is not tampered with. Availability: Ensure authorized users have access when needed. 1. Encryption: ------------------ Encryption is the process of converting plain text (readable data) into cipher text (unreadable form) using an algorithm and a key. Purpose: Ensure confidentiality so that even if attackers intercept the data, they cannot understand it. Types: Symmetric Encryption – Same key is used for encryption and decryption (e.g., AES, DES). Asymmetric Encryption – Two different keys: Public key for encryption Private key for decryption (e.g., RSA, ECC). 2. 🔑 Decryption: ------------------------ Decryption is the reverse process: converting cipher text back into plain text using the appropriate key. Only authorized parties with the correct decryption key can access the original data. Ensures secure communication even over insecure channels like the internet. ⚙️ How It Works (Example: Symmetric Encryption) Sender writes a message → "Hello World". Encryption algorithm + secret key → Cipher text "XyZ123!@#". Data is transmitted securely. Receiver uses the same key + algorithm → Recovers "Hello World". 🛡️ Applications in Cybersecurity Secure web traffic (HTTPS uses TLS encryption). Emails and messaging (end-to-end encryption in WhatsApp, Signal). File storage protection (BitLocker, VeraCrypt). Virtual Private Networks (VPNs) – secure internet connections. Banking & payments – protecting credit card and transaction data. 3. Encoding Purpose: Transform data into a different format for compatibility, transmission, or storage. Not for security. Example: Base64 encoding (used in emails, image-to-text representation). URL encoding (spaces → %20). Process: Input: "Hello" Encoded (Base64): "SGVsbG8=" 4. 🔄 Decoding The reverse of encoding: converting encoded data back into its original format. Anyone can decode if they know the scheme. Example: "SGVsbG8=" (Base64) → "Hello". 🔒 Encryption (for comparison) Used for security (confidentiality). Requires a key. Example: "Hello" → "XyZ123!@#" (ciphertext). 🔑 Decryption (for comparison) Reverse of encryption. Needs the correct decryption key. "XyZ123!@#" → "Hello". 📝 Key Difference: Encoding/Decoding = Just format conversion (no secrecy). Encryption/Decryption = Security + secrecy (requires keys).