Disclaimer : thanks to use my tuts only for legal purpose. Reverse Engineering is legal in a lot of countries but any if you only look at the source code. Modifications on copyrighted softwares are bad !

 

Hi,

 

Yeah, I don’t write something for a while so I decided to write a paper for beginner.

So, I’m going to show you how to write a keygen to solve a KeygenMe.

Some softwares checks for specific caracteristics when they check the licence key.

A basic example is : « if first letter is ‘w’ « . Then, any serial which begin with ‘w’ will be accepted.

Target + keygen : http://ge.tt/5xz3d6o2

Let’s start. The task will be to find the « routine » of the key verification system. SO let’s open our target in a decompiler.

Screenshot_1

Okay so it seems that it reads a file called « licence.bin » so just create one

It also seems that this licence.bin should have 3 lines.
The first is for the username

The second is the licence key (the interesting one)

And the last is for Expiration date.

If we read the bool flag2, we notice that the key should be a base64 string with a Y on first letter.

Now, we’ll go on visual studio to code a keygen !

We’ll code a function which will generate a base64 string. But, remember that the first letter has to be a Y so it means that the string that we’ll convert to base64 has to begin with a ‘a’

Here’s my code :

Screenshot_2

So to really have bunch of differents key, I decided to random a string and then add a ‘a’ to the beginning of this word. Then, I just convert this string to base64 and that’s all !

The last thing to do is to patch the date verification so just put a date in 2099 and you’re ok for years !

Here’s the final licence.bin :

Screenshot_3

That’s all for today. For any question, skype : MindSystem or email : mindlockreverser@gmail.com

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