A protocol that underlies other Internet packet protocols such as
UDP (User Datagram Protocol) and TCP/IP (Transmission Control Protocol/Internet Protocol)
to provide encryption. Sometimes the encryption/decryption is done by
LAN (Local Area Network)
card hardware. Some of the encryption algorithms used include HMAC-SHA1 extended
checksums for integrity protection and TripleDES-CBC and AES-CBC for
confidentiality. It is quite complicated to use. VPNs (Virtual Private Networks)
are a simpler way to get much the same effect.