Choose the statement that is NOT true regarding symmetric-key encryption:

Symmetric-key encryption uses a single shared secret key between parties, not separate private/public key pairs—that is a characteristic of asymmetric encryption. Option A correctly describes symmetric encryption (shared key), B is accurate (symmetric is computationally faster), and D correctly names symmetric algorithms (AES and DES). Only C falsely attributes asymmetric properties to symmetric encryption.

Step-by-step Derivation:
Analyze each statement against symmetric-key encryption fundamentals:

• A (TRUE): Symmetric encryption defines the shared secret key model—both sender and recipient possess and use the identical key.

• B (TRUE): Symmetric algorithms (AES, DES) use simpler mathematical operations (substitution, permutation) vs. asymmetric algorithms (RSA, ECC) which involve complex modular exponentiation. This makes symmetric encryption orders of magnitude faster.

• C (FALSE): Private/public key pair generation is the defining characteristic of asymmetric encryption (RSA, ECC), NOT symmetric encryption. Symmetric encryption relies on a single pre-shared key, with no concept of public or private key pairs.

• D (TRUE): AES (Advanced Encryption Standard) and DES (Data Encryption Standard) are textbook examples of symmetric algorithms.

The question asks for the NOT true statement. Answer is C.