Certified Information Systems Security Professional (CISSP) Practice Exam

The primary purpose of the Encapsulating Security Payload (ESP) in the IPsec protocol is to provide confidentiality by encrypting packet data. ESP operates at the network layer and is designed to protect the payload of IP packets by encrypting the data, thus ensuring that sensitive information remains private during transmission across potentially insecure networks.

While ESP also offers additional security services such as data integrity and authentication, its standout feature is encryption. This encryption makes it challenging for unauthorized parties to access the content of the packets, which is crucial for maintaining the confidentiality of sensitive information, such as in virtual private networks (VPNs), where the encapsulation of data is vital for secure communication.

Data integrity, authentication, and key management are components of the broader security framework, but they are not the primary focus of ESP. Instead, they are addressed by other mechanisms within IPsec or through complementary methods, ensuring a comprehensive approach to network security while ESP specifically targets confidentiality through encryption.