计算机英语 刘艺 王春生 第4版 Unit 10A（ppt课件）

1、Computer Security,1,学习交流课件,master useful terms understand what are threats to computer security and how to protect computer security,Requirements:,2,学习交流课件,terms or phrases 1 electronic break-in 电路中断 2 authorized user 授权的用户 3 destructive computer program 破坏性计算机程序 4 computer virus 计算机病毒 5 electronic

2、bulletin board 电子公告板 6 detection program 检测程序 7 virus checker 病毒检查程序 8 software piracy 软件侵权 9 primary storage 主存储器 10. power line 电力线，输电线,3,学习交流课件,10voltage surge 电涌，浪涌电压 12electronic component 电子器件 13 surge protector 浪涌电压保护器 14 power source 电源 15 circuit breaker 断路器 16 hard-disk drive 硬盘驱动器 17data-

3、entry error 数据输入错误 18deletion command 删除命令 19backup copy 备份的副本 20encryption program 加密程序,4,学习交流课件,act out get back (at) intend to introduceinto fillwith in the form of in case of be concerned with act as in the event of from time to time,实现，实行；出于 报复 打算(做)，企图(做). 往放置 用填满 以/用的形式；被看作 以防 关于;与有关；参与 起的作用，

4、担当 万一，倘若，如果发生 时常，不时,5,学习交流课件,Text,I. Threats to Computer Security Threats to computer security are computer crimes (including viruses and electronic break-ins) and natural and other hazards. 1. Computer Criminals A computer crime is an illegal action in which the perpetrator uses special knowledge o

5、f computer technology. Computer criminals are of four types:,一、计算机安全面临的威胁 计算机安全面临的威胁是计算机犯罪（包括病毒和电子闯入）以及自然与其他危害。 1、计算机罪犯 计算机犯罪是犯罪者使用专门计算机技术知识所做出的非法行为。计算机罪犯有4种类型：,6,学习交流课件,Q: What kind of things the employee steals from the employer? (1) Employees The largest category of computer criminals consists of

6、 those with the easiest access to computersnamely, employees. Sometimes the employee is simply trying to steal something from the employerequipment, software, electronic funds, proprietary information, or computer time. Sometimes the employee may be acting out of resentment and is trying to “get bac

7、k” at the company.,7,学习交流课件,(1) Employees The largest category of computer criminals consists of those with the easiest access to computersnamely, employees. Sometimes the employee is simply trying to steal something from the employerequipment, software, electronic funds, proprietary information, or

8、 computer time. Sometimes the employee may be acting out of resentment and is trying to “get back” at the company.,（1）雇员 人数最多的计算机罪犯类型由那些最容易接近计算机的人，亦即雇员，构成。有时，雇员只是设法从雇主那盗窃某种东西设备、软件、电子资金、专有信息或计算机时间。有时，雇员可能出于怨恨而行动，试图“报复”公司。,8,学习交流课件,(2) Outside Users Not only employees but also some suppliers or client

9、s may have access to a companys computer system. Examples are bank customers who use an automatic teller machine. Like employees, these authorized users may obtain confidential passwords or find other ways of committing computer crimes.,（2）外部用户 不仅雇员，而且有些供应商或客户也可能有机会访问公司的计算机系统。使用自动柜员机(取款机)的银行客户就是一例。像

10、雇员一样，这些授权的用户可能获取秘密口令，或者找到进行计算机犯罪的其他途径。,9,学习交流课件,Q:What is a hacker? What is the difference between hacker and cracker? (3) “Hackers” and “Crackers” Some people think of these two groups as being the same, but they are not. Hackers are people who gain unauthorized access to a computer system for the

11、fun and challenge of it. Crackers do the same thing but for malicious purposes. They may intend to steal technical information or to introduce what they call a “bomb”a destructive computer programinto the system.,10,学习交流课件,(3) “Hackers” and “Crackers” Some people think of these two groups as being t

12、he same, but they are not. Hackers are people who gain unauthorized access to a computer system for the fun and challenge of it. Crackers do the same thing but for malicious purposes. They may intend to steal technical information or to introduce what they call a “bomb”a destructive computer program

13、into the system.,（3）“黑客”与“非法侵入者” 有些人以为这两类人相同，其实不然。黑客获取对计算机系统未经授权的访问，是因为这种行为有趣和具有挑战性。非法侵入者行为相同，但出于恶意。他们可能企图窃取技术信息，或者往系统里放置他们所谓的“炸弹”一种破坏性计算机程序。,11,学习交流课件,(4) Organized Crime Organized crime has discovered that computers can be used just like legitimate business people use them, but for illegal purpose

14、s. For example, computers are useful for keeping track of stolen goods or illegal gambling debts. In addition, counterfeiters and forgers use microcomputers and printers to produce sophisticated-looking documents such as checks and drivers licenses.,（4）犯罪团伙 犯罪团伙发现，可以像合法的商业人员一样使用计算机，但为了非法的目的。例如，计算机可用

15、于跟踪赃物或非法赌债。另外，伪造者使用微机和打印机伪造支票、驾驶证等看起来很复杂的证件。,12,学习交流课件,2. Computer Crime Computer crime can take various forms, including: (1) Damage Disgruntled employees sometimes attempt to destroy computers, programs, or files. In recent years, computer viruses have gained wide notoriety. Viruses are programs t

16、hat “migrate” through networks and operating systems and attach themselves to different programs and databases.,2、计算机犯罪 计算机犯罪可能采取各种形式，包括： （1）破坏 不满的雇员有时企图破坏计算机、程序或文件。近年来，计算机病毒已是臭名远扬。病毒是一种程序，在网络和操作系统中“迁移”，并附加到不同的程序和数据库上。,13,学习交流课件,A variant on the virus is the worm. This destructive program fills a co

17、mputer system with self-replicating information, clogging the system so that its operations are slowed or stopped. The most infamous is known as the Internet Worm. In 1988, it traveled across North America, stopping thousands of computers along its way.,病毒的一个变种是蠕虫病毒。这种破坏性程序用自我复制的信息填满计算机系统，以阻塞系统，使系统的

18、运行减慢或停止。其中最臭名昭著的是因特网蠕虫。1988年，它行遍北美，途中使成千上万的计算机瘫痪。,14,学习交流课件,Viruses typically find their way into microcomputers through copied floppy disks or programs downloaded from electronic bulletin boards.Because viruses can be so seriouscertain “disk-killer” viruses can destroy all the information on ones s

19、ystemcomputer users are advised to exercise care in accepting new programs and data from other sources.,病毒一般是通过复制的软盘或从电子公告版上下载的程序进入微机。因为病毒可造成严重危害某些“磁盘杀手”病毒能毁坏系统上的所有信息，建议计算机用户在接受来自其他途径的新程序和数据时一定要小心。,V. 费劲心力,15,学习交流课件,Detection programs called virus checkers are available to alert users when certain k

20、inds of viruses enter the system. Unfortunately, new viruses are being developed all the time, and not all viruses can be detected. There are recommended procedures to reduce the risk of catching a computer virus and to minimize its potential damage.,现在有被称为病毒检查程序的检测程序可供使用，在某些种类的病毒进入系统时，向用户发出警告。不幸的是，

21、新的病毒不断被开发出来，而且并不是所有的病毒都能被检测出来。现在有降低计算机病毒感染风险并尽量减少其潜在破坏的推荐步骤。,16,学习交流课件,Q:What are the forms of theft? (2) Theft Theft can take many formsof hardware, of software, of data, of computer time. Thieves steal equipment, of course, but there are also “white-collar crimes.” Thieves steal data in the form o

22、f confidential information such as preferred client lists. They also use (steal) their companys computer time to run another business.,17,学习交流课件,(2) Theft Theft can take many formsof hardware, of software, of data, of computer time. Thieves steal equipment, of course, but there are also “white-colla

23、r crimes.” Thieves steal data in the form of confidential information such as preferred client lists. They also use (steal) their companys computer time to run another business.,（2）盗窃 盗窃可能采取多种形式盗窃硬件、盗窃软件、盗窃数据、盗窃计算机时间等。窃贼当然盗取设备，但也有“白领犯罪行为”。窃贼盗取被看作机密信息的数据，如优先客户名单。他们也使用（盗窃）公司的计算机时间处理其他事务。,以/用的形式,18,学习交

24、流课件,Unauthorized copyinga form of theftof programs for personal gain is called software piracy. Pirated software accounts for 40 percent of software used in the United States. The incidence of pirated software is even higher overseas in such countries as Italy (82 percent) and Thailand (92 percent).

25、,为个人利益而对程序进行的未经授权的拷贝也是一种盗窃形式，被称为软件盗版。盗版软件占到美国所使用的软件的40%。盗版软件在海外的比例甚至更高，如在意大利（82%）和泰国（92%）等国家。,19,学习交流课件,(3) Manipulation Finding entry into someones computer network and leaving a pranksters message may seem like fun, which is why hackers do it. It is still against the law. Moreover, even if the man

26、ipulation seems harmless, it may cause a great deal of anxiety and wasted time among network users.,（3）操控 进入某人的计算机网络并留下恶作剧式的信息，可能显得很好玩。这也是为什么黑客这样做的原因。这样做仍然是违法的。此外，即使这样的操作似乎没有危害，它也可能给网络用户造成很大的焦虑和时间浪费。,20,学习交流课件,Q:what kind of hazard can threat computer systems and data besides criminals? 3. Other Haz

27、ards There are plenty of other hazards to computer systems and data besides criminals. They include the following: Natural Hazards Natural forces include fires, floods, wind, hurricanes, tornadoes, and earthquakes. Even home computer users should store backup disks of programs and data in safe locat

28、ions in case of fire or storm damage.,3、其他危害 除了罪犯之外，计算机系统和数据还面临大量其他的危害。这包括如下危害： （1）自然危害 大自然的力量包括火灾、水灾、风、飓风、龙卷风和地震。即使家用计算机用户也应在安全地点保存程序与数据的备份磁盘，以防火灾或暴风的毁坏。,21,学习交流课件,(2) Civil Strife and Terrorism Wars, riots, and other forms of political unrest are real risks in some parts of the world. Even people

29、in developed countries, however, must be mindful that acts of sabotage are possible.,（2）内乱与恐怖主义 战争、暴乱和其他形式的政治动荡在世界的某些地区是实实在在的威胁。然而，即使是发达国家的人们，也必须保持警惕，在他们国家也可能发生破坏行为。,留神的、注意的,22,学习交流课件,(3) Technological Failures Hardware and software dont always do what they are supposed to do.For instance, too littl

30、e electricity, caused by a brownout or blackout, may cause the loss of data in primary storage. Too much electricity, as when lightning or other electrical disturbance affects a power line, may cause a voltage surge, or spike. This excess of electricity may destroy chips or other electronic componen

31、ts of a computer.,（3）技术故障 硬件和软件并不总是做它们该做的事。例如，电压不足或断电引起的电流过小，可能造成主存储器中的数据丢失。电流过大，如闪电或其他电干扰影响输电线时，可能造成电压浪涌或形成电压尖峰。这种电流过大可能毁坏计算机的芯片或其他电子元件。,23,学习交流课件,Most microcomputer users buy a surge protector, a device that separates the computer from the power source of the wall outlet. When a voltage surge occu

32、rs, it activates a circuit breaker in the surge protector,protecting the computer system.,大多数微机用户购买浪涌电压保护器，一种将计算机与壁装电源插座的电源分开的设备。电压浪涌发生时，就会激活浪涌电压保护器中的断路器，从而保护计算机系统。,24,学习交流课件,Another technological catastrophe is when a hard-disk drive suddenly “crashes,” or fails, perhaps because it has been bumped

33、inadvertently. If the user has forgotten to make backup copies of data on the hard disk, data may be lost.,还有一种技术灾难：硬盘驱动器突然“崩溃”或出故障，原因可能是不小心的碰撞。如果用户忘记在硬盘上备份数据，数据就可能丢失。,25,学习交流课件,(4) Human Errors Human mistakes are inevitable. Data-entry errors are probably the most commonplace. Programmer errors als

34、o occur frequently. Some mistakes may result from faulty design, as when a software manufacturer makes a deletion command closely resembling another command. Some errors may be the result of sloppy procedures. One such example occurs when office workers keep important correspondence under that no on

35、e else in the office knows.,（4）人为差错 人为差错不可避免。数据输入错误或许是最常发生的。程序员错误也经常发生。有些错误可能是由有毛病的设计所致，如软件制造商将删除命令设计得与另一个命令非常相似。有些错误可能起因于马虎的操作步骤。办公室工作人员将重要函件保存在办公室其他人不知道的文件名下，就是这样的一个例子。,26,学习交流课件,II. Measures to Protect Computer Security Security is concerned with protecting information, hardware, and software. Se

36、curity measures consist of encryption, restricting access, anticipating disasters, and making backup copies.,二、保护计算机安全的措施 安全与信息、硬件和软件的保护有关。安全措施包括加密、限制访问、预防灾难和制作备份。,anticipate：v. 预感、预料,27,学习交流课件,1. Encrypting Messages Whenever information is sent over a network, the possibility of unauthorized access

37、 exists. The longer the distance the message has to travel, the higher the security risk is. For example, an e-mail message on a LAN meets a limited number of users operating in controlled environments such as offices. An e-mail message traveling across the country on the National Information Highwa

38、y affords greater opportunities for the message to be intercepted.,1、给信息加密 每当信息通过网络发送，总是存在越权访问的可能性。信息传输的距离越远，安全风险就越大。例如，局域网上的电子邮件只会遭遇在办公室等受控环境中进行操作的有限数量的用户。而在国家信息高速公路上横穿国家的电子邮件，则提供了更多的被截取的机会。,提供机会,28,学习交流课件,Businesses have been encrypting, or coding, messages for years. They have become so good at i

39、t that some law enforcement agencies are unable to “wiretap” messages from suspected criminals. Some federal agencies have suggested that a standard encryption procedure be used so that law enforcement agencies can monitor suspected criminal communications.,工商企业给信息加密或译码已达多年。它们在这方面已十分擅长，致使有些执法机构难以“窃听

40、”疑犯发送的信息。一些联邦机构建议采用标准的加密程序，以便执法机构能够监控疑犯的通信。,29,学习交流课件,The government is encouraging businesses that use the National Information Highway to use a special encryption program. This program is available on a processor chip called the clipper chip and is also known as the key escrow chip.,政府鼓励使用国家信息高速公路

41、的工商企业采用一种专门的加密程序。这种程序可在一种处理器芯片上得到，该芯片称为加密芯片，通常也称为密钥托管芯片。,30,学习交流课件,Individuals are also using encryption programs to safeguard their private communications. One of the most widely used personal encryption programs is Pretty Good Privacy.,个人也使用加密程序来保护其私人通信。使用最广泛的个人加密程序之一是PGP加密软件。,31,学习交流课件,Q：How to r

42、estrict unauthorized access? 2. Restricting Access Security experts are constantly devising ways to protect computer systems from access by unauthorized persons. Sometimes security is a matter of putting guards on company computer rooms and checking the identification of everyone admitted.,2、限制访问 安全

43、专家不断设计新方法，用以保护计算机系统免于未经授权之人的访问。有时，保护安全就是派警卫看护公司计算机室和检查每个进入之人的身份证明。,32,学习交流课件,Oftentimes it is a matter of being careful about assigning passwords to people and of changing them when people leave a company. Passwords are secret words or numbers that must be keyed into a computer system to gain access

44、. In some “dial-back” computer systems, the user telephones the computer, punches in the correct password, and hangs up. The computer then calls back at a certain preauthorized number.,保护安全常常也是谨慎地将口令分配与人，并且在他们离开公司时更换口令。口令是秘密的单词或数字，必须键入计算机系统才能进行访问。在一些“回叫”式计算机系统情况下，用户打电话给计算机，键入正确的口令，然后挂断。计算机随后会回叫某个预先授

45、权的号码。,33,学习交流课件,Most major corporations today use special hardware and software called firewalls to control access to their internal computer networks. These firewalls act as a security buffer between the corporations private network and all external networks, including the Internet. All electronic

46、communications coming into and leaving the corporation must be evaluated by the firewall. Security is maintained by denying access to unauthorized communications.,今天，大多数大公司都使用被称为防火墙的专门硬件和软件，来控制对其内部计算机网络的访问。这些防火墙，在公司专用网络与包括因特网在内的所有外部网络之间，起到安全缓冲区的作用。所有进出公司的电子通信都必须经过防火墙的评估。通过拒绝未经授权的通信进出，来维护安全。,34,学习交流课

47、件,3. Anticipating Disasters Companies (and even individuals) that do not make preparations for disasters are not acting wisely. Physical security is concerned with protecting hardware from possible human and natural disasters. Data security is concerned with protecting software and data from unautho

48、rized tampering or damage.Most large organizations have a disaster recovery plan describing ways to continue operating until normal computer operations can be restored.,3、预防灾难 不做灾难预防工作的公司（甚至个人）是不明智的。物理安全涉及到保护硬件免遭可能发生的人为或自然灾难的破坏。数据安全涉及到保护软件和数据免遭非法篡改或毁坏。大多数大机构都有灾难恢复计划，描述继续操作直到计算机可以恢复正常运行的方法。,35,学习交流课件

49、,Hardware can be kept behind locked doors, but often employees find this restriction a hindrance, so security is lax. Fire and water (including the water from ceiling sprinkler systems) can do great damage to equipment.,硬件可以锁起来，但雇员常常觉得这种约束很麻烦，因此安全措施也就松弛了。火与水（包括来自天花板上喷洒灭火系统的水）可能对设备造成极大的损害。,36,学习交流课件,

50、Many companies therefore will form a cooperative arrangement to share equipment with other companies in the event of catastrophe. Special emergency facilities called hot sites may be created if they are fully equipped computer centers. They are called cold sites if they are empty shells in which har

51、dware must be installed.,因此，许多公司会与其他公司达成合作协议，在出现灾难的情况下合用设备。公司也可能创设专门的应急设施。这些设施如果是设备齐全的计算机中心就称为热场地，如果是必须安装硬件的空壳则称为冷场地。,万一、倘若,37,学习交流课件,4. Backing up Data Equipment can always be replaced. A companys data, however, may be irreplaceable. Most companies have ways of trying to keep software and data from

52、 being tampered with in the first place. They include careful screening of job applicants, guarding of passwords, and auditing of data and programs from time to time. The safest procedure, however, is to make frequent backups of data and to store them in remote locations.,4、备份数据 设备随时可以替换。然而，一个公司的数据可

53、能无法替代。大多数公司首先采取一些方法，力图防止软件和数据被篡改。这些方法包括仔细审查求职者，严守口令，以及时常检查数据和程序。然而，最保险的办法是经常制作数据备份，并将其存放在远距离地点。,38,学习交流课件,5. Security for Microcomputers If you own a microcomputer system, there are several procedures to follow to keep it safe: (1) Avoid Extreme Conditions Dont expose the computer to extreme conditi

54、ons. Direct sun, rain from an open window, extreme temperatures, cigarette smoke, and spilled drinks or food are harmful to microcomputers. Clean your equipment regularly. Use a surge protector to protect against voltage surges.,5、微机的安全 如果你拥有微机系统，可以遵照以下几个步骤保护其安全： （1）避开极端的环境 不要将计算机暴露在极端的环境中。直接照射的阳光、从开着的窗户飘进的雨、极端温度、香烟的烟以及溅出的饮料或食物对微机都是有害的。经常清洁你的设备。使用浪涌电压保护器预防电压浪涌。,39,学习交流课件,(2) Guard the Computer Put a cable lock on the computer. If you subscribe or belong to an online information service, do not leave password