# Diffie–Hellman key exchange

### Table of Contents

## 1 - About

Diffie–Hellman key exchange is a key exchange.

in 1974, the GCHQ mathematician and cryptographer, Malcolm J. Williamson developed it.

In the Diffie–Hellman key exchange scheme:

- each party generates a keypair
- each party distributes the public key to the party adverse
- each party compute a shared secret (key) with the public key

The shared secret can be used, for instance, as the key for a symmetric cipher.

## 2 - Articles Related

## 3 - SSL

Secure Sockets Layer (SSL) uses:

- Diffie–Hellman key exchange if the client does not have a public-private key pair and a published certificate in the public key infrastructure
- Public Key Cryptography if the user does have both the keys and the credential.