IPsec

The IP level is in the TCP/IP network most essential one, IP takes the network level agreement, its safety mechanism may provide the transparent cover type safekeeping of security to its upper formation each kind using the service. Therefore, the IP security is the entire TCP/IP security foundation, is the network security core. IPSec is the present only one kind can provide the safety control for any form Internet correspondence the agreement. The IPSec permission provides the security which one by one data stream or connects one by one, can therefore realize the very careful safety control. Regarding the user, then may regarding different need to define the different rank safekeeping of security (i.e. different protection intensity IPSec channel). IPSec was the network data transmission provides the data confidentiality, the data integrity, the data origin authentication, anti-to rebroadcast and so on safe service, caused the data when through the public network transmission, did not need the worry to monitor, to tamper with and fabricates. 　　IPSec is through uses each kind of encryption algorithm, the confirmation algorithm, the seal agreement and some special safekeeping of security mechanism realizes these goals, but these algorithms and the parameter are the preservation in carry on IPSec correspondence both sides SA (Security Association, security alliance), when in both sides SA establishment match, the both sides might carry on IPSec to correspond. 　　Has mainly used the IPSec technology in hypothesized private network (VPN).