In IPSec, what does a Security Association (SA) establish between two hosts?

In IPSec, what does a Security Association (SA) establish between two hosts?

• A. Key exchange only
• B. Data encryption only
• C. Authentication only
• D. Trust between the hosts and agreement on security parameters

Answer: (D)

In IPsec, a Security Association defines how protected traffic between two hosts will be handled. It creates a trusted relationship and an agreement on the exact security parameters that will be used for that communication, such as which encryption and integrity algorithms, the keys, the SPI that identifies the SA, and the lifetime of the protection. The key exchange process (often via IKE) is used to establish these parameters, but the SA itself is the contract that governs protection for the traffic. Because it covers both the trust between the hosts and the specific security parameters to apply, it’s the best description. The other options describe only a single aspect (key exchange, encryption, or authentication) and don’t capture the full purpose of an SA.

In IPsec, a Security Association defines how protected traffic between two hosts will be handled. It creates a trusted relationship and an agreement on the exact security parameters that will be used for that communication, such as which encryption and integrity algorithms, the keys, the SPI that identifies the SA, and the lifetime of the protection. The key exchange process (often via IKE) is used to establish these parameters, but the SA itself is the contract that governs protection for the traffic. Because it covers both the trust between the hosts and the specific security parameters to apply, it’s the best description. The other options describe only a single aspect (key exchange, encryption, or authentication) and don’t capture the full purpose of an SA.