1. 9 1 ADVANCED WEB TOPICS Browser Extensions and Internet Security New Perspectives on THE INTERNET

2. 9 2 Objectives Learn how to enhance your Web browser capabilities with browser extensions Discover where to locate popular browser extensions for Microsoft Internet Explorer Visit a Web site where you can test a plug-in

3. 9 3 Objectives Investigate Internet security and learn about secrecy, integrity, necessity, and privacy Identify several ways to defend against security risks Learn about copyright and intellectual property rights on the Internet

4. 9 4 Browser Extensions Allow a Web browser to perform tasks it was not originally designed to perform. Plug-ins – programs that a browser starts to display or play a specific file. Helper applications or helper apps – “help” a browser to display or play a file.

5. 9 5 What Are Plug-Ins and Helper Applications? Plug-ins differ slightly from helper applications in the way they run. Helper applications are independent programs that are stored on your computer and are activated automatically when needed. Plug-ins do their work inside the browser and do not activate standalone programs.

6. 9 6 What Are Plug-Ins and Helper Applications?

7. 9 7

8. 9 8 Figure 9-3

9. 9 9 Browser Extension Categories Document and productivity Image viewer Multimedia Sound player Video player VRML and 3-D

10. 9 10 Document and Productivity Browser Extensions Let you use a browser to read documents. Files saved in PDF format require Adobe Acrobat Reader. Microsoft Office lets the browser start Word, Excel and other Office files.

11. 9 11 Image Viewer Browser Extensions Image viewer displays graphics. Display different picture file formats. More than one graphic viewer will be needed to view the different kinds of pictures on the Web. AutoDesk displays line drawings in the proprietary Drawing Web format. Real estate agents use iPix.

12. 9 12 Multimedia Browser Extensions Largest category of browser extensions. Shockwave provides animated interfaces, interactive advertisements and product demonstrations, multi-user games, and streaming CD-quality audio. Flash displays high-impact user interfaces, interactive online advertising, and animation. Automatically installed with Internet Explorer and Navigator.

13. 9 13 Multimedia Browser Extensions Figure 9-4

14. 9 14 Sound Player Browser Extensions Let your Web browser play sounds. Beatnik and Crescendo deliver high-quality interactive music and sound on the Web. RealPlayer delivers MIDI music in very small file sizes. RealPlayer plays streaming audio and video and uses buffered play.

15. 9 15 Video Player Browser Extensions Deliver movies to Web browsers. QuickTime technology plays video, sound, and music. QuickTime movie format is computer- platform neutral. QuickTime’s format was adopted by the ISO as the starting point for developing an improved and unified digital media storage format.

16. 9 16 Video Player Browser Extensions

17. 9 17 VRML and 3-D Browser Extensions Virtual Reality Modeling Language is a programming language that creates three- dimensional environments that can mimic known worlds or define fictional ones. Cosmo Player is a VRML player that lets you experience three-dimensional Web worlds without having special three-dimensional graphics acceleration hardware installed.

18. 9 18 VRML and 3-D Browser Extensions

19. 9 19 Finding Browser Extensions

20. 9 20 Finding Browser Extensions

21. 9 21 Finding Browser Extensions

22. 9 22 Finding Browser Extensions

23. 9 23 Installing and Testing Browser Extensions

24. 9 24 Security Overview Protection of assets from unauthorized access, use, alteration, or destruction. Physical Security – tangible protection devices Logical Security – uses non-physical protections Countermeasure – procedure that recognizes, reduces, or eliminates a threat

25. 9 25 Security Overview Figure 9-13

26. 9 26 Security Overview Secrecy prevents unauthorized data disclosure and ensures the authenticity of the data’s source. Integrity prevents unauthorized data modification Necessity prevents data delays or denials.

27. 9 27 Security Overview Copyright is the protection of expression.

28. 9 28 Security Overview

29. 9 29 Security Threats Integrity Threat – also know as active wiretapping Delay and Denial Threats – disrupts normal computer processing or deny processing entirely Intellectual Property Threats – use material without the owner’s permission

30. 9 30 Security Threats Threat Delivery Mechanisms – –A hacker uses Trojan horses, viruses, and worms to attack computers. Computer Emergency Response Team has teams around the world to recognize and respond to computer attacks.

31. 9 31 Security Threats

32. 9 32 Security Countermeasures The security countermeasures necessary for Internet transactions should ensure that the transaction or message being sent: –Cannot be read by anyone except the intended recipient. –Is tamperproof, ensuring that no one was able to modify its contents or delete it entirely. –Is authored by the person who claims to be the sender.

33. 9 33 Security Countermeasures A digital certificate contains: The certificate holder’s name, address, and e-mail address A special key that “unlocks” the digital certificate, thereby verifying the certificate’s authenticity The certificate's expiration date or validity period A trusted third party, called a certificate authority, which verifies the person’s identity and issues the digital certificate

34. 9 34 Security Countermeasures Figure 9-17

35. 9 35 Security Countermeasures

36. 9 36 Secrecy and Privacy Encryption – process of coding information using a mathematical-based program and a secret key to produce a string of characters that is unreadable Decryption – the reverse of encryption Two-types of encryption used today: –Symmetric (private-key) encryption –Asymmetric (public-key) encryption

37. 9 37 Secrecy and Privacy Figure 9-19

38. 9 38 Secrecy and Privacy Figure 9-20

39. 9 39 Protecting Web Commerce Transactions Sockets Layer (SSL) – widely used, nonproprietary protocol that travels as a separate layer on top of the TCP/IP protocol SSL uses both symmetric and asymmetric encryption and keys to ensure privacy. Session keys exist only during a single, active session between the browser and server.

40. 9 40 Protecting Web Commerce Transactions Internet Explorer’s Secure State Indicator Navigator’s Secure State Indicator

41. 9 41 Protecting Web Commerce Transactions

42. 9 42 Protecting Web Commerce Transactions Figure 9-24

43. 9 43 Integrity A message digest function program is used to maintain the integrity of an e-mail message. This program produces a number called a message authentication code or MAC. –It must be impossible or costly to reverse the MAC and produce the original message. –The MAC should be random to prevent creating the original message form the MAC. –The MAC must be unique to the message so there is an extremely small chance that two messages could ever produce the same MAC.

44. 9 44 Integrity Figure 9-25

45. 9 45 Necessity A necessity attack can slow down processing, completely remove an item, or deny its use. Programs that travel with applications to your browser can execute on your PC can be dangerous. May have the following components: –Java –JavaScript –ActiveX

46. 9 46 Necessity

47. 9 47 Security Countermeasures Whenever possible, avoid completing Web page registration forms. Omit your resume and other personal information from your Web page. Set your Web browser to limit or disable cookies. Purchase and use a virus detection program. Download software and files from known and trustworthy sources.