CISSP Study Guide: IP Security Protocol (IPSec)

IPSec is a set of standards that support protected transfer of information across an IP internetwork. IPSec Encapsulating Security Payload (ESP) Tunnel method supports the encapsulation and encryption of entire IP datagrams for secure transfer across a private or public IP internetwork. IPSec requires the two computers engaged in communications to arrange the highest common security policy. The source of communication implements IPSec to encrypt the data before it transmits the data across the network. Once data is received, the destination computer decrypts the information prior to passing it to the destination process. This encryption and decryption process is done transparently.