# Diffie-Hellman

Also found in: Acronyms.

## Diffie-Hellman

(cryptography)
A public-key encryption key exchange algorithm.

FAQ.

## Diffie-Hellman

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. See elliptic curve cryptography and key management.

Very Clever There is more computation in actual practice, but this example, which uses tiny numbers to illustrate the concept, shows a very clever mathematical approach. Each party raises the common number, which is 2 in this example (this has nothing to do with binary-- it is just the number "2") to a random power and sends the result to the other. The received number is raised to the same random power. Note that both parties come up with the same secret key, which was never transmitted intact.
References in periodicals archive ?
Diffie and Hellman [11] did a seminal work in designing key exchange protocol and proposed the first one-round key exchange protocol called Diffie-Hellman (DH) key exchange protocol.
8], [9], [10] proposed CLIQUES protocol suite that consist of group key agreement protocols for dynamic groups called Group Diffie-Hellman (GDH).
For commonly used 1024-bit keys, it would take about a year and cost a "few hundred million dollars" to crack just one of the extremely large prime numbers that form the starting point of a Diffie-Hellman negotiation.
Moreover, Nguyen doesn't directly give the security reduction of their ring signature scheme, but we provide the security proof in the random oracle model under the k-strong Diffie-Hellman assumption.
2]common secret keys if they send n Diffie-Hellman public keys in a single round of message exchange.
Key Exchange: Elliptic Curve Diffie-Hellman (ECDH) or Elliptic Curve Menezes-Qu-Vanstone (ECMQV) - Draft NIST Special Publication 800-56
New storage-specific standards and protocols such as Diffie-Hellman CHAP are emerging for the storage infrastructure.
5 and DSA standards and Diffie-Hellman Key Exchanges is also included.
The 7956 accelerates a variety of IPSec and SSL/TLS protocols, including DES, Triple DES, AES (with 128, 192, and 256-bit key lengths), and ARC4 encryption; MD5, SHA-1 hashing and authentication; RSA, DSA, SSL, IKE, and Diffie-Hellman public key support; 3,072-bit modular arithmetic and exponentiation, plus true Random Number Generation (RNG).
Next JumpStart creates an encryption key using the Diffie-Hellman protocol, which has long been at the heart of highly secure web-based e-commerce facilities such as the Secure Socket Layer (SSL).
In addition to conventional password protection, Puffer employees 2048-bit Diffie-Hellman public key cryptography that allows you to securely share your files and messages with other people without the need to share secret passwords.

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