PC Underground: Phần 2

Part 1 of the is serial Tài liệu Pc Underground to part 2 of you will continue to learn about relevant issues such as: protect your know-how protection tricks, memory management, programming other PC components,... Invite you to consult the lecture to learn more about this content.
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PC Underground: Phần 29. Protect Your Know-how: Protection Tricks Protect Your PC und e r g r o un d Know-how: Protection Tricks Chapter 9Most experts agree using a dongle is currently the best protection against illegal copying. However, usinga dongle to protect programs is impractical. The dongle, if it is to provide reliable protection, could costseveral times more than the program; low cost dongles provide only minimal security.A more reliable method is using a CD-ROM. The CD offers a certain degree of security for at least tworeasons: 1. Although its possible to write directly to a CD, the hardware required is quite expensive. Unless the program is illegally copied by a professional, the CD offers a certain degree of security. 2. An enormous quantity of data can be stored on one CD-ROM. Most users will think twice about copying 150 Meg onto their hard disk for only one program.The disadvantage of using a CD-ROM is that many users still do not have a CD-ROM drive. Therefore, yourprogram cannot be used by those who do not have a CD-ROM drive.Therefore, if using a dongle or a CD-ROM is not possible, you have only one more possibility: You mustbuild copy protection into your program. Remember, there is no copy protection that a dedicated hackercannot defeat. However, you can make a hackers life much more difficult.The protection tricks well talk about in this chapter become more important in this age of rising economiccrime. No one likes to see their ideas and technology stolen.The tricks well talk about probably will not protect your programs from the professional hacker, but theywill frustrate the would-be debugger expert. You will also find these tricks used in many professionalprograms.Dissecting ProgramsThere are many tools that can be used to debug. Well introduce a few of the most popular ones to you inthis section.Your first thought when we mention tools is probably programs like PC Tools or the Norton Utilities.However, we are not talking about this type of program here. Instead, well discuss several useful programsthat will make your life with your computer easier. By the time you finish reading this section, youll befamiliar with the following types of programs: 229Chapter 9Protect Your Know-how: Protection Tricks PC und ergr oun d Ø Compression/decompression programs Ø Debugging programs Ø Hex editorsRemoving the camouflage: Compression/decompression programsUsing compression/decompression programs like PKZIP or WinZip, you can compress files so they do notoccupy as much space on the hard drive. Many compression programs compress .EXE and .COM files intoself-extracting EXE files or COM files that decompress automatically when they are run and do not requirea separate decompression program.The one area of caution with compression programs is the possibility of a virus. If you compress a file thatis infected with a virus, the virus itself is also compressed with the program and cannot be recognized byvirus detection software.We cannot discuss all the specific compression/decompression programs here. For more in-depthinformation on compression/decompression programs see PKZIP, LHARC & Co. from Abacus (6thprinting).Debugging programs: Turbo DebuggerTurbo Debugger, bundled by Borland with C(++) and Pascal, is one of the most popular debuggingprograms. Using Turbo Debugger, you can step through both your source code and .EXE or .COM files. Youare also able to set breakpoints with Turbo Debugger. You can allow your program to execute to these pointsand then, from this point onward, work through the program one step at a time.In the following paragraphs well explain how you can analyze a program with this powerful tool andmonitor specific variables. However, if you need more detailed information on Turbo Debugger, refer toany of the several books available for either Borland C(++) or Borland Pascal.Running Turbo DebuggerFirst, you must determine which version of Turbo Debugger you would like to use. You can use thestandard Turbo Debugger. This works with any memory manager, but also requires a large amount ofmemory. Alternatively, you can also use Turbo Debugger386 . However, for this debugger you have to enterthe following line in your CONFIG.SYS:Device = TDH386.S ...