Which algorithm is used for key exchange in secure communications?

The Diffie-Hellman algorithm is specifically designed for securely exchanging cryptographic keys over a public channel. Its main purpose is to enable two parties to generate a shared secret key without having to transmit the key itself over the network. This is achieved through the use of mathematical principles involving exponentiation and modular arithmetic.

When the two parties use the Diffie-Hellman method, they each choose a private key and then generate a public key from it. They share their public keys with each other and, using their private keys, each party can compute the same shared secret. This key can then be used for symmetric encryption to secure communication, all without needing to send the key directly.

In contrast, while RSA is also a cryptographic method, it serves primarily for secure data transmission and digital signatures rather than key exchange. AES is a symmetric encryption algorithm, which means it requires a pre-shared key for encryption and decryption, making it unsuitable for initial key exchange. Rivest Cipher typically refers to a family of encryption algorithms, among which RC4 is commonly known, but these do not specialize in key exchange either.

Therefore, Diffie-Hellman stands out as the correct answer because it is explicitly designed for the purpose of securely establishing a shared