The Diffie-Hellman key agreement protocol (also called exponential key agreement) was developed by Diffie and Hellman in 1976 and published in the groundbreaking paper "New Directions in Cryptography." The protocol allows two users to exchange a secret key over an insecure medium without any prior secrets. Interlink Networks' implementation of the SPEKE authentication method uses a hash of the password as the Diffie-Hellman generator. This prevents man-in-the-middle attacks.
A key exchange protocol allowing the participants to agree on a key using a non-secure communication method.
A public, key-exchange algorithm that is used for securely establishing a shared secret over an insecure channel. During Phase II negotiations, the Diffie-Hellman group prevents someone who intercepts your key from deducing future keys that are based on the one they have.