Which defines symmetric encryption?

• A. Uses a public/private key pair
• B. Relies on a shared secret key
• C. Requires a trusted third party to issue keys
• D. Only for digital signatures

Answer: (B)

Symmetric encryption hinges on using the same secret key for both encryption and decryption. Because both parties share this key, it must be kept confidential, and its security directly protects the message. This approach is fast and well-suited for securing large amounts of data, with common algorithms like AES.

Describing a public/private key pair points to asymmetric encryption, which uses different keys for encryption and decryption. Requiring a trusted third party to issue keys relates to key distribution and management in some systems, not the encryption method itself. Digital signatures are typically tied to asymmetric cryptography, where a private key creates the signature and a public key verifies it, not the symmetric approach.