While the Internet is inherently insecure, businesses still need to preserve the privacy of data as it travels over the network. To help do that, the Internet Engineering Task Force an international group of network designers, operators, vendors, and researchers concerned with the evolution of (71) has developed a suite of (72) called Internet Protocol Security (IPSec).
IPSec creates a standard platform to develop secure networks and electronic (73) between two machines. Secure tunneling via IPSec creates (74) connections in a network through which data packets can move. It creates these tunnels between remote users and within a local network. It also (75) each data packet in a new packet that contains the information neccessary to set up, maintain and tear down the tunnel when it’s no longer needed.

A．conformance

B．circuitlike

C．searching

D．secrecy

银汞化合物调和24h后产生0.05%~0.01%的膨胀有利与洞壁密合，下列膨胀较少的是（）

A.缩短调和时间

B.锌含量大于1%

C.减少充填压力

D.铜含量2%

E.适当增大合金粉粒度