DES加密算法采用的密码技术是(18),它采用(19)位密钥对传输的数据进行加密,著名的网络安全系统Kerberos采用的是(20)加密技术。公钥密码是(21),常用的公钥加密算法有(22),它可以实现加密和数字签名。
A. 对称密钥密码技术
B. 公钥密码技术
C. 数字签名技术
D. 访问控制技术
听力原文:W: Eastern Airlines Agency. Good Morning.
M: Good Morning. I want to book a round-trip ticket.
W: Where are you flying from, and what's your destination, sir?
M: From Montreal to Toronto.
W: What day do you want to fly?
M: I want to leave on Monday the 24th and return on Friday. Do you have any flights in the afternoon?
W: Yes, we do. By the way, will that be first class or economy class? How many people are there in your party?
M: Just myself. And I'd like economy class.
W: All right, there are seats still available. Would you prefer a window, aisle or center seat?
M: Window, please. Thank you.
What does the man book?
A round-trip air ticket.
B. A one way ticket.
C. A single room.