我国在实行城市最低生活保障制度的过程中，许多地方对申请享受这项制度的人实行张榜公布，这种“公示”制度给申请者带来耻辱感，甚至会阻碍某些符合条件者的申请。这种情况属于哪种功能类型？（）

A.正功能

B.负功能

C.显功能

D.潜功能

___39___ is used to ensure the confidentiality, integrity and authenticity of the two end points in the private network. ___40___, an application-layer protocol, authenticates each peer in an IPSec transaction. IKE negotiates security policy, determining which algorithm may be used to set up the tunnel. It also handles the exchange of session keys used for that one transaction.

Networks that use ___41___ to secure data traffic can automatically authenticate devices by using by using ___42___, which verify the identities of the two users who are sending information back and forth. IPSec can be ideal way to secure data in large networks that require secure connections among many devices.

Users deploying IPSec can ___43___ their network infrastructure without affecting the applications on individual computer. The protocol suite is available as a software-only upgrade to the network infrastructure. This alows security to be implemented without costly changes to each computer. Most important, IPSec allows interoperability among different network devices, PCs and other computing systems.

39（）

A. Certificate

B. Encryption

C. Tunnel

D. Presentation