Reverse Engineer

What do you mean by "reverse engineer?" I have heard this word several times especially in the world of hacking, but... can someone tell me what it really meant?

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An entity claiming to be Jerome Tan wrote:
: 
: What do you mean by "reverse engineer?" I have heard this word several =
: times especially in the world of hacking, but... can someone tell me =
: what it really meant?
: 

Reverse engineering is the process of taking a piece of executable code,
be it a Win95 program or firmware for a cellular phone eeprom, and
running it through a disassembler.  The disassembler converts the
machine code into assembly instructions.  From there, a person with
a lot of spare time, a good understanding of compiler design, and a lot
of caffeine can translate the assembly instructions into a higher level
language (ie. C, C++, VisualBasic).  The first part is easy (and writing
a disassembler is a good project for upper-level Comp Sci courses), but
the second part is a real bear and people with the knowledge and 
drive to do it have my respect.

- -- 
    Mark Rogaski   | Why read when you can just sit and |      Member
  GTI System Admin |         stare at things?           | Programmers Local
  wendigo@gti.net  | Any expressed opinions are my own  |     # 0xfffe
 wendigo@pobox.com | unless they can get me in trouble. |     APL-CPIO


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Mark Rogaski <wendigo@pobox.com> writes:
> : What do you mean by "reverse engineer?" I have heard this word several =
> : times especially in the world of hacking, but... can someone tell me =
> : what it really meant?
> : 
> 
> Reverse engineering is the process of taking a piece of executable code,
> be it a Win95 program or firmware for a cellular phone eeprom, and
> running it through a disassembler.  The disassembler converts the
> machine code into assembly instructions.  From there, a person with
> a lot of spare time, a good understanding of compiler design, and a lot
> of caffeine can translate the assembly instructions into a higher level
> language (ie. C, C++, VisualBasic).  The first part is easy (and writing
> a disassembler is a good project for upper-level Comp Sci courses), but
> the second part is a real bear and people with the knowledge and 
> drive to do it have my respect.

Small correction: oftentimes one is trying to figure out the 'secret' 
algorithm used by the program, and that can be done by analyzing the
assembler just as well. I did this a few times to break 'secret'
cryptosystems. 

Certain programs encrypt their executable code and decrypt it at runtime
to make reverse engineering more difficult.

---

Dr.Dimitri Vulis KOTM
Brighton Beach Boardwalk BBS, Forest Hills, N.Y.: +1-718-261-2013, 14.4Kbps

On Wed, 17 Jul 1996, Jerome Tan wrote:

> What do you mean by "reverse engineer?" I have heard this word several times especially in 
the world of hacking, but... can someone tell me what it really meant?
> 

Speaking of reverse engineering something, what is a program that will 
allow you de-compile a visual basic app?

Joe