What is the Diffie-Hellman key exchange 

The Diffie-Hellman key exchange is a cryptographic method for securely exchanging encryption keys over a public channel. Key aspects include:

1. **Public Key Exchange:** Allows two parties to generate a shared secret key over an insecure channel.

2. **Mathematical Basis:** Relies on the difficulty of solving discrete logarithm problems in modular arithmetic.

3. **Initial Setup:** Each party selects a private key and computes a public key based on a common base and prime number.

4. **Shared Secret:** Both parties combine their private keys with the other's public key to compute the same shared secret independently.

The shared secret can then be used for encrypting communications between the parties.