How many phases does the Internet Key Exchange (IKE) have?

The Internet Key Exchange (IKE) operates in two distinct phases. In the first phase, the two parties authenticate each other and establish a secure communication channel by negotiating the security policies and key materials. This phase can utilize either pre-shared keys or public-key encryption techniques for authentication, leading to the creation of a secure channel that allows subsequent key exchanges to occur securely.

In the second phase, the actual keys for the IPsec (Internet Protocol Security) security associations are negotiated. This phase focuses on the establishment of the final keys used for data encryption and integrity, utilizing the secure channel created in Phase 1.

By breaking down the key exchange process into these two phases, IKE provides a robust framework for ensuring secure key negotiation and exchange, which is critical for establishing a secure IPsec VPN connection.