__imp__'s KeygenMe #4
| Download Keygenme4.zip, 6 kb (password: crackmes.de) Browse contents of Keygenme4.zip No protection placed, so you can decompile it.
Difficulty: 2 - Needs a little brain (or luck) | RatingWaiting for at least 3 votes View profile of __imp__ » |
Solutions
Solution by Stardust, published 25. aug, 2010; download (36 kb), password: crackmes.de or browse.
Stardust has rated this crackme as awesome.
Discussion and comments
| Xspider 26. Apr 2010 | i guess it uses MD5 isn't right? |
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| __imp__ Author 26. Apr 2010 | Right, it does:) |
| Xspider 27. Apr 2010 | ugh the rest O_o i don't understand anything :p i'm not familiar with .net assemblies ^^ |
| Falo 14. May 2010 | If Math.Abs(clsCalc.func6(lArr2) / clsCalc.func6(lArr1) - dec3) < (0.0000000000000003D) Then MessageBox.Show("Congratz! Please write a tutorial.", "Correct!", MessageBoxButtons.OK, MessageBoxIcon.Exclamation) the Key is part of the calculation of the key, also some random numbers are part of the calculation, this is not really a Keygen Target... because of the Random Numbers, i was able to crash the app with Name = Name, Password = 000000000000000-0 -> Div / 0 error |
| __imp__ Author 17. May 2010 | @Falo: Normally, the crash you encountered wouldn't have happened, though there might be another reason for crashing. I fixed it in the new version. The algo stayed intact. As to everything else, the target is easily keygennable despite random numbers (I have a working keygen). |
| __imp__ Author 30. May 2010 | Does anyone have an idea? |
| Stardust 18. Aug 2010 | I have an idea... It seems, that your random numbers are vectors of an triangle (you test also if the vectors are really not collinear). Then you calculate the area of the triangle and compare it with an area of an tetragon build out of vectors of this triangle (with factor of MD5Hash of Name and the serialnumber). Yes (for me) serial is just a floating point number. Maybe I have a look at some math books. Very nice crackme (till now)! |
| Stardust 19. Aug 2010 | Finally I found the "equation": Name: "Stardust" Serial: "242944697829282-1" or Name: "__imp__" Serial: "199297538882454-1" I try to write a tutorial. It is a very good crackme with interesting mathematic. |
| __imp__ Author 22. Aug 2010 | Nice job, Stardust! You are absolutely right about the underlying geometry. Looking forward to your tutorial! |
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