Miscellaneous I

Lloyd Colling

http://members.xoom.com/lcolling/

 Q: This is likely a very silly question. I need to create a .cab file, but I have no

idea how to do it...

Answer: Microsoft has a tool for it. See 

http://msdn.microsoft.com/workshop/management/cab/cab.asp

You can also get a shareware version of a Cabinet Manager (easier to use than the

MS tool) from

http://www.microlognet.com/

Jos

or you can download a free *.cab tool at:

http://home.t online.de/home/lars.hederer/english.htm

 Q: Why we can reengineer Java byte code (.class file) back to Java source

code? But why binary .exe file we are unable to do it? What is the significant

difference?

Answer: AFAIK, Java byte code goes back to _some_ source, not to the original

source. So, reverse engineering is limited.

> But why binary .exe file we are unable to do it? What is the significant difference?

(a) There is more than one way to do something using C++.

(b) There are highly optimizing C++ compilers.

(c) You won t get the original source anyway. See (a).

Imagine that your C++ code contains inline functions. The compiler is free do place

the body of it replacing a call, or instantiate the function and provide a real call to it.

First, there is no way to know when it is going to do one or the other. Second, with

some code inlined, how to decide what _was_ an inline function and what wasn t?

So, the answer is: the distances between the levels of abstraction between byte code

and Java source and between machine code and C++ source are significantly

different. The bigger the distance, the less possible it is to recreate the source code.

Victor Bazarov

in java bytecode all the original variable names are kept. in an exe file smaller

symbols are used.

Some .exe decompilers are good enough to convince a jury that the "original" source

code was reconstituted. See the Microsoft v. Stac case for an example.

Java is easier, but C is still possible.

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