Which of the following is NOT an asymmetric encryption system?

The Data Encryption Standard (DES) is categorized as a symmetric encryption system, which means it uses the same key for both encryption and decryption processes. In symmetric encryption, the security relies on the assumption that the key remains confidential between the parties involved in communication.

In contrast, asymmetric encryption systems employ a key pair—comprising a public key for encryption and a private key for decryption. This separation of keys allows for functionalities such as secure key exchange and digital signatures, which are essential for modern cryptographic applications.

By identifying DES as the option that does not fit within the realm of asymmetric encryption, it underscores the fundamental distinction between symmetric and asymmetric systems, emphasizing the unique characteristics of asymmetric techniques like RSA, ECC, and DSA, all of which utilize key pairs to facilitate secure communications and data integrity.