什麼是反工程
反工程(reverse engineering)指將軟體及硬體分解或者解析，解明它們的結構，使用方法及目的，組成部品與要素技術的原理。在程式的領域，包含闡明組件間的關係的和分析系統的基本方法的行為。
反工程多用於企業製作其他公司產品的互換產品。其中以大企業愛普生公司套用反工程開發出NEC的PC-9800系列的互換電腦最為有名。企業的產品大多申請了專利或者擁有著作權，所以，在利用解析結果時，要避免侵害到智慧財產權。
雖然一般不被看好，但通過指正使用說明書與實際安裝的出入，發現安全漏洞及程式錯誤等，對於維護系統及加強安全等方面有一定的幫助。
Whatisreverseengineering
Reverse engineering is taking apart an object to see how it works in order to duplicate or enhance the object. The practice, taken from older industries, is now frequently used on computer hardware and software. Software reverse engineering involves reversing a program's machine code (the string of 0s and 1s that are sent to the logic processor) back into the source code that it was written in, using program language statements.
Software reverse engineering is done to retrieve the source code of a program because the source code was lost, to study how the program performs certain operations, to improve the performance of a program, to fix a bug (correct an error in the program when the source code is not available), to identify malicious content in a program such as a virus or to adapt a program written for use with one microprocessor for use with another. Reverse engineering for the purpose of copying or duplicating programs may constitute a copyright violation. In some cases, the licensed use of software specifically prohibits reverse engineering.
Someone doing reverse engineering on software may use several tools to disassemble a program. One tool is a hexadecimal dumper, which prints or displays the binary numbers of a program in hexadecimal format (which is easier to read than a binary format). By knowing the bit patterns that represent the processor instructions as well as the instruction lengths, the reverse engineer can identify certain portions of a program to see how they work. Another common tool is the disassembler. The disassembler reads the binary code and then displays each executable instruction in text form. A disassembler cannot tell the difference between an executable instruction and the data used by the program so a debugger is used, which allows the disassembler to avoid disassembling the data portions of a program. These tools might be used by a cracker to modify code and gain entry to a computer system or cause other harm.
Hardware reverse engineering involves taking apart a device to see how it works. For example, if a processor manufacturer wants to see how a competitor's processor works, they can purchase a competitor's processor, disassemble it, and then make a processor similar to it. However, this process is illegal in many countries. In general, hardware reverse engineering requires a great deal of expertise and is quite expensive.
Another type of reverse engineering involves producing 3-D images of manufactured parts when a blueprint is not available in order to remanufacture the part. To reverse engineer a part, the part is measured by a coordinate measuring machine (CMM). As it is measured, a 3-D wire frame image is generated and displayed on a monitor. After the measuring is complete, the wire frame image is dimensioned. Any part can be reverse engineered using these methods.
The term forward engineering is sometimes used in contrast to reverse engineering.
