In the original description, the Diffie–Hellman exchange by itself does not provide authentication of the communicating parties and is thus vulnerable to a man-in-the-middle attack. ... A method to authenticate the communicating parties to each other is generally needed to prevent this type of attack.

Can Diffie-Hellman be used for authentication?

The Diffie-Hellman (DH) method of authenticating a user is nontrivial for an intruder to crack. Authentication is based on the ability of the sending system to use the common key to encrypt the current time, which the receiving system can decrypt and check against its current time. ...

What does Diffie-Hellman do?

The Diffie–Hellman (DH) Algorithm is a key-exchange protocol that enables two parties communicating over public channel to establish a mutual secret without it being transmitted over the Internet. DH enables the two to use a public key to encrypt and decrypt their conversation or data using symmetric cryptography.