Index
> DOS > Can someone help me to reverse engineer the algorithm? |
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AsmGuru62
I can try.
Can you post the code? |
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29 Aug 2014, 21:01 |
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chuck
AsmGuru62 wrote: I can try. Hi AsmGuru62 thanks for your quick response, I enclose the file and please ask if you require more info
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29 Aug 2014, 21:57 |
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ACP
I'd suggest posting original file and not IDA listing in MS Word document if you really want somebody to take a peek at your file.
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29 Aug 2014, 22:16 |
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questlima
chuck wrote: Hi all reverse engineer huh  why not use Ollydbg best debugger out there and
yes why not post the application if you want to get help no no i am no good in reversing apps anyway happy reversing  _________________ Linux command are not what you intended to learn but your were forced to learn it, without it you will be like a sitting duck on your beautiful newly installed Linux desktop:) |
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30 Aug 2014, 04:07 |
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ACP
Ollydbg can't debug DOS EXE files...
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30 Aug 2014, 09:17 |
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chuck
ACP wrote: I'd suggest posting original file and not IDA listing in MS Word document if you really want somebody to take a peek at your file. Here is original file the calc only computes a 4 digit code if the 4 bytes are in a specific relation to each other. I don't know if this helps but here are some examples 01 5F 36 FF = 0010 but also computes 0014 0018 plus others 01 5F 36 FE = 0011 also 0311 0711 01 5F 37 F7 = 0013 also 0053 0093 1003 01 5F 32 E2 = 0015 FA 48 19 BF = 1475 FA 48 19 A3 = 1479 01 5F 37 00 = 0000 plus about 100 other codes |
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30 Aug 2014, 10:15 |
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AsmGuru62
Good.
So, what is this program does? If I start this EXE you posted in DOS - what it will do? |
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30 Aug 2014, 10:56 |
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chuck
it is a calculator for computing the code from a .bin file that has been read from a chip in a car radio.
you have to know in the .bin file where the 4 bytes are, you then enter them into the calc and it will give you code basically I hae no problem getting code I just want to know the algo it uses to compute the code |
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30 Aug 2014, 11:17 |
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baldr
chuck,
That program seems to be compiled from BASIC source (QuickBASIC?). |
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30 Aug 2014, 12:57 |
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chuck
baldr wrote: chuck, I can see from the doc file that it uses subroutines Xor And etc calculations but my knowledge of what it is actually doing is practicly zilch. I would like to know things like, does it do a sum before Xoring what bytes are used in the Xor etc.etc. I know 2 numbers of the code just from the 1st byte for example if first byte is FD then the code will always begin with 1 and somewhere in the code will be a 4 (I know the sequence for all 1st bytes) |
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30 Aug 2014, 13:40 |
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questlima
why dos i was wondering it will be good if x86 OS become absolute like 16bit then even the dev and the end user will have no issue with x86 and then x64 bit apps this is just a personal issue trying to use kernel debuggers on a x64 OS sometimes it gives me a BSOD
_________________ Linux command are not what you intended to learn but your were forced to learn it, without it you will be like a sitting duck on your beautiful newly installed Linux desktop:) |
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30 Aug 2014, 19:36 |
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ACP
baldr wrote: chuck, Yes baldr - you seemed to be right. I don't have any experience with Microsoft Basic compiled code but... Chuck: did you even tried to contact the author of this program: Nick Sukonnikov sukonnikov(at)vinnitsa.com? |
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30 Aug 2014, 20:11 |
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chuck
ACP wrote:
yes I have tried to contact author with no success |
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30 Aug 2014, 23:45 |
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Matrix
chuck wrote:
They put the code in the car radio so dumb thiefs will not have a working radio without your code if they steal your radio from your car |
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13 Sep 2014, 08:51 |
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