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Old 08-20-2003, 02:27
Ghrialton
 
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My first "crack"...

Wow, what a feeling. Typing in the reg and getting the right message. Pretty weak protection, though. I didn't have to look at ANY assembly code, so it's not a "real" crack, I guess. Here's how it went down.

VB 5.0 program, compiled to p-code.
Tools: smartcheck.
Protection: 30-day trial and disable, name and serial.

I opened smartcheck, and ran my target prog from within it, and looked at what happened when I entered a wrong name and serial. Error message, but before this was a trim() call and a bunch of mid() calls. I don't know exactly what they do, but I know they deal with string handling in VB, so I figured I had my code. Looking at each of the mid() lines individually I saw that most were only subtly changed, but the last one had a dramatic difference. Compare:

string = 0021C32C ;Hex code for something?
= "C" ;This is the username I entered.

string = 002182D4 ;More hex.
= "222411160131" ;AHA!

I tested this with different usernames, and found that it changed with different usernames. When I tried it as a serial, however, I got the error message. So I took my kid to school, did some shopping, and some thinking about why it didn't work. I mean, it was doing one of two things in my mind... 1) It was generating a string of numbers based on the name, and then using that string (mabye a val()) to create a serial based on an unseen algorithim, or 2) it was actually generating the correct serial, but I was using it correctly.

While I was out, I thought about previous (cracked) versions of this program, and remembered that the serials weren't just a string of numbers... So I googled for a crack for the old version, and observed a serial, and it's format.

xxx-xxxxx-xxxx

So I tried my serial and username again, this time with hashes in place... BINGO!

Well, that's how it happened. I'd like to think that it's a good example of a "zen" crack, but I'm too new to the game to claim that. I've done alot of reading, learned a little asm, and still have lots to do. Mabye I should write a keygen for it, might be a good learning experience.

Thanks for the ftp, and for this informative forum. Apologies if this is an inappropriate place for this.

ps. The ironic thing is that I was going to pay for this software. I acutally took steps to do so. I discovered that it is abandonware and I could not contact the programs author.
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Old 08-20-2003, 05:22
Ghrialton
 
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OK, I've been searching for tutorials on encryption, but am having little luck finding what I need. I'm looking for a tutorial, website, or thread that discusses making keygens, with an eye to someone who does not exactly know the algorithm is (cracker) vs. someone who already knows it (software author).

Will anyone point me in the right direction?
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  #3  
Old 08-21-2003, 21:34
Ghrialton
 
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Well, nevermind. It turned out to be a simple substitution cypher, and the keygen took like 10 minutes to write once I figured it out.
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