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.

A method for exchanging a secret key over an untrusted medium in such a way as to preserve the secrecy of the key. The two parties both contribute random data that factors into the final shared secret. The fundamental problem with this method is authenticating the party with whom you exchanged keys. The simple Diffie-Hellman protocol doesn't do that. One must also use some public-key authentication system such as DSA. See Also: DSA, Station-to-station protocol

A cryptographic key exchange method developed by Whitfield Diffie and Martin Hellman in 1976. Also known as the "Diffie-Hellman-Merkle" method and "exponential key agreement," it enables parties at both ends to derive a shared, secret key without ever sending it to each other. Using a common number, both sides use a different random number as a power to raise the common number. The results are then sent to each other. The receiving party raises the received number to the same random power they used before, and the results are the same on both sides. http://www.answers.com/diffie-hellman

A key exchange protocol allowing the participants to agree on a key over an insecure channel.

Diffie-Hellman (D-H) key exchange is a cryptographic protocol that allows two parties that have no prior knowledge of each other to jointly establish a shared secret key over an insecure communications channel. This key can then be used to encrypt subsequent communications using a symmetric key cipher.