Symmetric Encryption

Problem

You need to encrypt large amounts of data efficiently. Every message must be encrypted and decrypted quickly enough to keep up with the connection.

Solution — Symmetric Encryption

Symmetric encryption uses the same secret key to encrypt and decrypt data. Both sides must first obtain the same secret key securely. Establishing that key is a separate step; symmetric encryption uses it to protect the data.

Client      secret K      Server
   └──────────┬────────────┘
              ↓
        encrypt/decrypt

Algorithms such as AES can process large amounts of data efficiently.

Core idea: symmetric encryption uses shared secret key material for fast encryption.