Question about reverse engineering on main.hex

TonyN · Guest

hi,
My clients request me to give them the hex file so that they can burn it into the board. I just wonder if they have the main.hex file, can they do the reverse engineering to obtain to the source code? How is easy they can do that? is there a way i can do to prevent that happen?

I use PIC18F722 and my code space is about 64K and memory space is about 70% of the PIC18F722 RAM

Thanks,

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

They can set the PIC type in MPLAB, then use the Import function to
load it. Then they can see the whole ASM code with View / Program
Memory. Any competent programmer can figure out what the code is
doing. Going to C source would be a little bit harder but not impossible.
But the ASM code is enough to reverse engineer the functionality.

Sergio · Joined: 16 Oct 2003 Posts: 11 Location: Arkansas, USA

It would be very hard but not impossible.

On the other hand why would they want to do that? They just paid you to create the program.

BTW, unless you specified in the contract, if they pay you then that source code belongs to them.

Cheers,
Sergio
_________________
Sergio

Guest · Posted: Sat Apr 11, 2009 8:38 am

I have had a similar request.

What I do is remote desktop into their machine and I load with protect on, the hex file. So no reverse engineering can be done.

FvM · Joined: 27 Aug 2008 Posts: 2337 Location: Germany

asmallri · Joined: 12 Aug 2004 Posts: 1635 Location: Perth, Australia

asmallri · Joined: 12 Aug 2004 Posts: 1635 Location: Perth, Australia

ratheeshbr · Joined: 26 Jan 2011 Posts: 31

Is it possible to view the assembly code from program memory in C?

temtronic · Posted: Wed Feb 09, 2011 6:59 pm

Reverse enginneering from the .hex file into the source code is not that difficult as PICs only have 35 instructions compared to the 180+ the Z-80 had back 25+ years ago.
True, you won't get the author's labels but generic ones, and of course no comments. You also know the PIC type which helps, as well as any peripherals on the PCB.
When the 16c84s came out it became a challenge, more of a mind game, to reverse engineer the code. And like every 'lock' there is a 'key' to open the door.

The final question 'Is it possible to view the assembly code from program memory in C?' yes, if you mean, can I create a C program to read the program memory contents of another PIC.

ratheeshbr · Joined: 26 Jan 2011 Posts: 31

I am having a hex file. I use the import function in Mplab and I can now see the Assembly listing. But its difficult. Can I convert it into C, so that i can easily understand?

temtronic · Posted: Wed Feb 09, 2011 9:40 pm

You'll get a much better education and appreciation for the PIC if you learn the 35 instructions of the PIC. Just grab the databook, open to the chapter on your PIC and printout the disassembled code.
It is NOT that hard, especially with the huge amount of information available on the Web.
Since you already know what the program does as well as the hardware you should be able to follow the 'flow of the code'.
Sure you could download a 'reassembler to C' but there's NO knowledge gained in that 'cheat'.