Crosys's Keygenme 2008 v1.0
| Download Keygenme2008-1_a.zip, 151 kb (password: crackmes.de) Browse contents of Keygenme2008-1_a.zip Keygen only solution.
Difficulty: 4 - Needs special knowledge | Send a message to Crosys » View profile of Crosys » |
Solutions
Solution by fusss, published 14. jul, 2008; download (61 kb), password: crackmes.de or browse.
fusss has not rated this crackme yet.
Discussion and comments
| HMX0101 11. Jul 2008 | Wooooowww.... nice to see you write sometime again! I guess this one is very harder :) Will take a look... thanks mate ;) |
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| Crosys Author 11. Jul 2008 | Hey mate, dont expect too much , its not very hard.. :) Have a nice time.. |
| zart 11. Jul 2008 | That one was mucho fun mate :) Nice to see another good keygenme... I try to write up a tutorial and keygen for it later one ;) |
| Crosys Author 11. Jul 2008 | Thank you zart, you finished it? |
| zart 11. Jul 2008 | Did a quick analyses of it - and understand most of it -- was able to get a valid key. Though this took me my whole extended lunch break! Hhahah - much fun... It was a nice break from trying to do that damned SDDecoder -- If I have a chance sometime soon I'll write up a tutorial and finish it fully with a keygen :) |
| Crosys Author 11. Jul 2008 | 1st serial is designed for beginners and 2nd serial no. is more harder.. |
| zart 11. Jul 2008 | Agreed! Experience will help people for the second serial a lot! |
| andrewl.us Moderator 11. Jul 2008 | Being a damn number theorist helps for the second serial.. |
| lord_Phoenix 11. Jul 2008 | Got it. Wanna something more. ps. If you want - i can write a small solution |
| andrewl.us Moderator 11. Jul 2008 | Constants: c0: 0x100A8731C4A45A47A0906B10 c1: 0xA8E276C5FDF00FA415C2283C c2: 0x8DA9A1C93977236D (prime) c3: 0xC4921F47591E845FB382B3C7 (prime) Serial syntax: "<dw0>-<dw1>-<dw2>" Let inv = 1/dw2 (mod c2) Let hash = Big(first 8 bytes of (MD5(dw0))) I think this is serial acceptance requirement: dw1 == [[c0^(hash*inv(mod c2)) * c1^(dw1*inv(mod c2))] (mod c3)] (mod c2) Is this correct? I don't have near the math skill to do this. Is it a particular cryptosystem we can study? Zart, I don't believe a word you say. Post your serial? |
| Ox87k 15. Jul 2008 | My god, beautiful keygenme Crosys! Unfortunatelly i miss that one, i was away from home and now it seems to be too late :) @fusss: Great solution man ;) |
| the hoax 30. Apr 2009 | Solved. I liked the first part best, since the DSA implementation was pretty straight forward. |
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