Codebreaking (A CHALLENGE)

Hi all,

A few days ago Dimitri (aka Dimava) sent me an exe file (attached in a zip) where you enter in a 5 letter keyword and it would output a 5 letter password. Now the problem is that the program was made in 1992 and the src is no longer around, yet dimitri needs to know the algorithm for creating the password from the keyword.

I have attached the program and i have also some notes from me playing around with it:

(key) = (pass)
AAAAA = UWKWP
AAABA = TWKWP
AAACA = SWKWP
AAADA = ZWKWP

BBBAB = UXHZS
BBBBB = TXHZS
BBBCB = SXHZS
BBBDB = ZXHZS

CCCAC = UYIYR
CCCBC = TYIYR
CCCCC = SYIYR
CCCDC = ZYIYR

DDDAD = URFBU
DDDBD = TRFBU
DDDCD = SRFBU
DDDDD = ZRFBU

If you look at the above list you can see that the letter 4th along in the keyword some how by changing that it relates to the first letter of the password so like A seems to match to U and B to T. I have a few more notes too)

Can anyone help to attempt to crack the keyword to password algorithm ?

I'm willing to help :)

The 3rd letter becomes the first one. The letters varie with their position - it seems to me that their Ascii value is increased by some ammount.

Since its encryption its likly to use some sort of random number or some **** like that which is quite hard to crack. Why not use a program like Windasm32 and look at the assembly in the program that encrypts/decrypts it then from that u will have a better idea of how it works or make a crack for it

we have the Assembler code, but it makes no sense to us. We also have the Turbo C code for it, but we can't understand that either.


~~~Dimava~~~

Why not break it with brute force. Shouldn't take too long with only 5 letter password. Just need to write an app to do the permutations for you.

noo.. you dont see, i need the algorythem of this key generator

~~~Dimava~~~

Why do you need the algo?
And post the turbo C source.

It doesn't look like this is doing any kind of randomization..

I'm going to look at this a bit more, but I don't know if I'm actually going to come up with something..

here's the source

MAN!!!

Do you expect to easily write a decrypting program for something that has been encrypted with +80kbs of code?!

That's some fine looking code :D

Well, you've got the source, so don't you have the algorithm? Shouldn't be too hard to convert VB (he says thanking his lucky stars that he's not the poor bastard whose got to do said conversion) :)

- gaffa

how would I convert it though? I seached the web for over an hour, and I can't find a C to VB converter.... any ideas?


~~~Dimava~~~

To be honest - no.

The "C" code is just glorified assembler. The best you could do woyuld be to convery sub by sub, but it's messy as all hell, with calls left right and centre.


I don't know of any decent code scrubbers.

- gaffa

WHAT'S THAT CODE????????

That's a very interesting topic you guys got here.

I got the code I'll work on it.
Hope I can get something.

thanks Gush

Here's the code a little more readable.

It's the same source code, why is that?

when I open it from my Hard drive I read it fine.

??????????

Well i (coz i know C++ unlike dimava) had a look at it but it looks seriously messed and it would not compile on my pc due to like 400errors and 200warnings. So.....

A very very big thanks for this help :D