问题 填空题

加密和解密算法的操作都是在一组密钥控制下完成的,它们分别称为 【3】 和解密密钥。

答案

参考答案:加密密钥

解析: 加密是信息保护的重要措施。加密和解密是一组相反的算法过程,前者通过一种算法将明文转换为密文,后者通过相反的算法将密文转换为明文。这种算法过程分别在加密密钥和解密密钥的控制下完成。

单项选择题
阅读理解

When the recent research was analyzed(分析), it was found that a lot of people wanted free pictures or free music from the Web. If it couldn’t be free, then they wanted it “new” or at least at a low price. It seems that 70 percent of people aged 16 to 24 download music online but only 1 in 40 tracks are bought legally.

Thus, some companies are planning to give all of their music away for free. The music will be totally free except that you will have to pay with your time by watching advertisements. This will be perfect for those who have lots of time but little money.

The Web has encouraged a belief that things can be free, or at least very cheap. It seems that everyone is looking for a good deal on the Web. The desire for free objects is part of the nature of the Web because the Web is about self-service and self-service is all about being free, cheap, fast and convenient. It’s interesting how words change their meaning. Stealing has now become file sharing, but it’s not really stealing, is it?

Free is a funny word. We all know that very little is really for free. If we go searching on the Web for free music, we know—or should know—that there are risks involved. However, it doesn’t matter. We still want free things, or at least the sense that we’re getting a real bargain and that at a minimum we’re saving time.

What can be the worst experience on the Web? A site that charges us high prices and wastes our time.

小题1:What is the best title for the text?

A.The Nature of the Web

B.The Web and the Culture of “ Free”

C.Stealing and File Sharing

D.What Does the Word “ Free” Mean?小题2:Why do some companies “ sell” their music for free?

A.Their music is not popular and is out of date.

B.Most people have lots of time but little money.

C.Their music can’t be sold new or for a low price.

D.They can earn money from the advertisements added in the music.小题3:Which of the following can best describe the belief of the Web?

A.Risky behaviour

B.Stealing

C.File sharing

D.For fun.