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1、,Unit 27 Text Computer Security,New Words and Expressions,security si5kjuEriti n. 安全, 保证 unauthorized5Qn5C:WEraizd adj. 未被授权的，未经认可的 replicate 5replikeit v. 复制， 重复 pinpoint 5pinpCint v. 指示正确位置, 确认 confidentiality 9kCnfidenFi5Aliti n. 机密性 incorporate in5kC:pEreit v. 合并, 结合 institute 5institju:t vt. 建立
2、, 开始 preserve pri5zE:v vt. 保护, 保藏 integrity in5teriti n. 完整(性), 完全,encryption in5kripFEn n. 加密, 编密码 unintelligible 5Qnin5telidVEbl adj. 难解的,莫名其妙的 interception 9intEsepFEn n. 拦截, 截段 fabrication 7fAbri5keiFEn n. 伪造物,制作 nullify 5nQlifai vt. 使无效, 废弃 secure si5kjuE adj. 安全(放心)的 theft Weft n. 偷, 行窃 verify
3、 5verifai vt. 验证,查证, 核实 as a whole 从整体来看,总的来说 range fromto 分布在的范围内,Technical Terms,an encoded card 编码卡 information bank 信息库 degree of confidentiality 机密程度 overlapping controls 重叠控制,Notes,1. The techniques developed to protect single computers and network-linked computer systems from accidental or in
4、tentional harm are called computer security. 为防止单机或网络上联接的计算机系统无意或有意损坏而研制的技术叫计算机安全学。 该句的主干结构是The techniquesare called computer security; developed to 是过去分词短语，用作定语。 2. Data may be protected by such basic methods as locking up terminals and replicating data in other storage facilities. 采用锁定终端和把数据拷贝到其它储
5、存设备上的基本方法就可以保护数据。 such as 意为：象 那样的，as 后是省去了are 的定语从句。如：Such materials as (are ) copper and silver are called good conductors. 像铜和银那样的材料称之为良导体。,3. More sophisticated methods include limiting data access by requiring the user to have an encoded card or to supply an identification number or password. 更
6、先进的方法包括让用户拥有编码卡，或者提供身份(证)号码或口令来限制数据存取。 句中 to have an encoded card or to supply 是动词不定式作宾语 the user 的补足语。 4. By transforming data so that it is unintelligible to the outside observer, the value of an interception and the possibility of a modification or a fabrication are almost nullified. 将数据进行变换，使外界看
7、起来都是无规律的，这样截取的数据就没有用，修改或伪造的可能性都将成为泡影。 By transforming data so that it is unintelligible 是介词短语作方式状语, 其中含一个 so that 引导的结果状语从句。,5. since data that cannot be read generally also cannot be changed. (由于)加密的数据一般不能读出，也不能更改， 该状语从句的主谓结构是：datacannot be changed; 其中含一个定语从句。,Exercises I. Choose the one that best
8、completes each of the following statements according to the text : 1. According to the author，computer security is _. A. a program B. a technique C. a computer system D. a method 2. Which of the following is not a data protecting method? A. Locking up terminals B. Replacing data in other storage fac
9、ilities C. Supplying a password before data access D. Ranking data frequently in computer files 3. Obviously, security in computer is a very important issue. The word “issue” may best means _. A. something printed B. A final conclusion C. an important point D. A final result 4. Interpreting data may
10、 be encoded in various ways to prevent _persons from or even copying the material. A. special B. unauthorized C. personal D. private,B,D,C,B,5. The goal of computer_ is to institute controls that preserve secrecy, integrity, and availability. A. machine B. procedure C. integrity D. security 6. The m
11、ost powerful tool in providing computer security is _. A. computing B. coding C. transforming D. locking 7. _ is an important tool in computer security. A. Nullified B. Security C. Encryption D. Facilities 8. Programs must be secure enough to _ outside attack. A. exclude B. prevent C. control D. dev
12、elop,D,B,C,A,II. Put the following phrases into Chinese: 1. build-in safeguards 2. accidental and intentional harm 3. an encoded card 4. information bank 5. unauthorized persons 6. an identification card,1. 内置的防护措施 2. 无意或有意损坏 3. 编码卡 4. 信息库 5. 未经授权的人(用户) 6. 身份(证)号码,B. Reading New Words and Expression
13、s virus 5vaiErEs n. 病毒菌素 alteration 7C:ltE5reiFEn n. 变更 foremost 5fC:mEust adj. 最重要的，最初的 render 5rendE vt. 提出 obsolete 5CbsEli:t adj. 荒废的 prior to 预先的；在前的 content vt. 使满足 n. 内容,Technical Terms,intrusive viruses 入侵病毒 viral strain 病毒株 integrity checkers 完整性检验程序 memory-resident monitors 内存驻留监视程序 disrup
14、tive instructions 入侵性(破坏性)的指令 virus signatures 病毒特征码,Exercises,Decide whether the following statements are true or false： 1. A computer virus is a small program replicating by attaching a copy of themselves to another program. 2. In many cases, a virus may contain no intentionally harmful or disruptive instructions at all. 3. Shell viruses invade an existing program and actually insert a portion of themselves into the host program. 4. Source code viruses work by replacing part
