Functioning at the network layer of the Open Systems Interconnection model, the packet-encryption device at the originating site encrypts the entire packet, including the IP header, and provides it with a new header.

• 由于是在“开放系统互连”模型的网络层上起作用的，始发站上的包加密装置对整个包加密，包括IP报头，都提供一个拥有新报头的包。