问题 问答题 简答题

阐述计算机网络信息安全中的主动防御保护技术。

答案

参考答案:

主动防御保护技术一般采用数据加密、身份鉴别、存取控制、权限设置和虚拟专用网络等技术来实现。

(1)数据加密。密码技术被公认为是保护网络信息安全的最实用方法。对数据最有效的保护就是加密,因为加密的方式可用不同手段来实现。

(2)身份鉴别。身份鉴别强调一致性验证,验证要与一致性证明相匹配。通常,身份鉴别包括验证依据、验证系统和安全要求。

(3)存取控制。存取控制表征主体对客体具有规定权限操作的能力。存取控制的内容包括人员限制、访问权限设置、数据标识、控制类型和风险分析等,它是内部网络信息安全的重要方面。

(4)权限设置。规定合法用户访问网络信息资源的资格范围,即反映能对资源进行何种操作。

(5)虚拟专用网技术。使用虚拟专用网(VPN-Vutual Private Network)或虚拟局域网(VLAN)技术。VPN技术就是在公网基础上进行逻辑分割而虚拟构建的一种特殊通信环境,使其具有私有性和隐蔽性。VPN也是一种策略,可为用户提供定制的传输和安全服务。

阅读理解

阅读理解

     Today, we complete our story about the influential English writer William Shakespeare. He wrote

plays and poems during the late fifteenth and early sixteenth centuries, which remain very popular today.

     During earlier times, people would probably have learned several ancient Roman and Greek plays.

It was not unusual for writers to produce more current versions of these works. For example, in

Shakespeare's play The Comedy of Errors Shakespeare borrowed certain details from the ancient

Roman writer Plautus. For his play Macbeth, Shakespeare most likely used a work on Scottish history

by Raphael Holinshed for information. Shakespeare might have borrowed from other writers, but the

intensity(强度)of his imagination and language made the plays his own. While many plays by other

writers of his time have been forgotten, Shakespeare and his art live on.

     Shakespeare was also influenced by the world around him. He described the sights and sounds of

London in his plays. His works include observations about political struggles, the fear of diseases, and

the popular language of the city's tradesmen. Shakespeare's knowledge of the English countryside is

also clear. His works include descriptions of deep forests, local flowers, and the ancient popular

traditions of rural people.

     It would be impossible to list all of the ways in which Shakespeare's works have influenced the world

culture. But the first and greatest example would be his great influence on the English language. During

his time, the English language was changing. Many new words from other languages were being added.

Shakespeare used his sharp mind and poetic inventiveness to create hundreds of new words and rework

old ones. For example, he created the noun forms of "critic",  "mountaineer" and "eyeball". Many common expressions in English come from his plays, including "pomp and circumstance(装腔作势)"from Othello,

"full circle(绕圈子)" from King Lear, etc. The list of cultural creations influenced by Shakespeare is

almost endless. From paintings to television to music and dance, Shakespeare was well represented.

Shakespeare's plays have been translated into every major language in the world.

     Shakespeare became a wellknown writer during a golden age of theater. His years of hard work paid off.

1. Shakespeare might have learnt some information from ancient Roman works in________.

A. King Lear  

B. The Comedy of Errors

C. Macbeth  

D. Othello

2. Why could Shakespeare's works survive his time?

A. Because there were so few people writing plays in his time.

B. Because he produced too many works that nobody else could do.

C. Because he was a rich and influential person of his time.

D. Because his works were rich in imagination and language.

3. Shakespeare's greatest influence should be on________.

A. the English language  

B. paintings

C. television  

D. music and dance

4. The passage is mainly about ________.

A. an introduction to Shakespeare's life and his works

B. the main features and styles of Shakespeare's plays

C. how culture influenced Shakespeare and he influenced culture

D. Shakespeare's greatest influence on the world culture

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