gen-define-symmetric-versus-asymmetric-encryption-and-give-one-s-d084

Define symmetric versus asymmetric encryption and give one short worked example.

# Symmetric vs Asymmetric Encryption ## **Symmetric Encryption** - Uses the **same key** for both encryption and decryption - Faster and more efficient - Challenge: securely sharing the key between parties - Examples: AES, DES, 3DES ## **Asymmetric Encryption** - Uses a **key pair**: public key (encryption) and private key (decryption) - Slower but solves key distribution problem - Public key can be freely shared; private key stays secret - Examples: RSA, ECC --- ## **Simple Worked Example: Caesar Cipher (Symmetric)** **Key:** Shift by 3 positions **Encryption:** - Plaintext: `HELLO` - Shift each letter forward by 3: - H → K - E → H - L → O - L → O - O → R - **Ciphertext:** `KHOOR` **Decryption:** - Ciphertext: `KHOOR` - Shift each letter backward by 3: - K → H - H → E - O → L - O → L - R → O - **Plaintext:** `HELLO` Both sender and receiver must know the same key (shift by 3) to communicate.