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VPN(Virtual Private Network,虚拟专用网络)连接是跨互联网建立的一条临时的安全的连接,是一条穿越不安全公共网络的可靠的隧道。()
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A.虚拟专用网(VPN,Virtual Private Network)就是通过一个公用网络建立一个临时的、安全的连接,是一条穿过混乱的公用网络的安全、稳定的隧道
B.VPN的核心技术是隧道技术。隧道是利用一种协议传输另一种协议的技术,封装是构建隧道的基本手段,它使得IP隧道实现了信息隐蔽和抽象。隧道技术包括数据封装、传输和解包在内的全过程
C.实现VPN的隧道协议有:PPTP、DNS、FTP、TCP/IP、SSL、MPLS 等
D.针对不同的用户要求,VPN有三种解决方案:远程访问虚拟网(Access VPN)、企业内部虚拟网(Intranet VPN)和企业扩展虚拟网(Extranet VPN)
选出应填入下面一段英语中______内的正确答案。
Public Key Infrastructure (PKI) service providers offer organizations fully integrated PKI-managed services designed to secure Intranet, Extranet, Virtual Private Network (VPN), and e-commerce applications. PKI solutions can enable a number of security services, including strong authentication and non-repudiation oftransaction.
eToken enables the users of PKI systems to generate and store(1)and digital certifications inside the token, creating a secure environment and allowing full portability and maximum ease of use. eToken Pro can also perfonn sensitive on-chip(2)operations, ensuring that users' keys are never exposed to PC environment, eToken eliminates the need to store(3)and keys on a hard disk or browser file, or to transmit them across the Internet/Extranet, assuring peace-of-mind and confidence during online communications.
A digital signature is created using the private key of an individual to ensure the validity of his request. This technology can be used to guarantee(4)of various transactions. The strength of either the authentication level or the digital signature relies on the level of protection offered to the private key. eToken PRO offers the maximum level of security, since it enables the use of the private key for signing and authenticating inside the eToken.
The most secure use of authentication involves enclosing at least one certificate with every signed message. The message(5)verifies the certificate using the CA's public key. If the sender's public key is legitimate, the recipient verifies the message's signature. Digital signatures created with a private key are verified with the digital certificate containing the public key.
We can infer that current virtual reality devices ______.
A.still need improving to create a perfect virtual world
B.are already perfect to create a virtual world
C.are unable to create a virtual world
D.are harmful to users of virtual reality
A.a computer simulated environment
B.a real world
C.many worlds
D.a real situation
A.ti:(virtual)orti:(digital)andti:(service)
B.ti:(virtual)andti:(digital)andti:(service)
C.ti:(virtual)andti:(service)orti:(digital)
A.Patients. B.Peasants.
C.Pilots. D.Architects.
The best game to buy 15 Alien Control 3 or Virtual History.
A. none
B. either
C. any
D. some