Linux System - Table 12 > Packages - Table 1 & 2 > OpenSwan

IPSEC is Internet Protocol SECurity. It uses strong cryptography toprovide both authentication and encryption services. Authenticationensures that packets are from the right sender and have not beenaltered in transit. Encryption prevents unauthorised reading of packetcontents. These services allow you to build secure tunnels throughuntrusted networks. Everything passing through the untrusted net isencrypted by the IPSEC gateway machine and decrypted by the gateway atthe other end.