What protocol is referred to by the acronym DHE?

The correct answer is Diffie-Hellman Ephemeral. This protocol is a key exchange method that allows two parties to establish a shared secret over an insecure channel. The term "ephemeral" refers to the use of temporary keys that are generated for a single session. This enhances security because, even if the temporary keys are compromised, they cannot be reused for future communications, thereby protecting past session integrity.

In secure communications, especially over the internet, ensuring that session keys are not static is crucial for safeguarding against various types of attacks. Diffie-Hellman Ephemeral is widely used in protocols like TLS (Transport Layer Security) to provide confidentiality during the exchange of cryptographic keys. Thus, it plays a key role in maintaining the security and privacy of online communications.

Other options do not accurately represent a well-known security protocol recognized in cryptography or key exchange methodologies.