cyclops's Spear
| Download spear.zip, 52 kb (password: crackmes.de) Browse contents of spear.zip A simple crackme.If u understand the algo itz a 2 min task
Difficulty: 1 - Very easy, for newbies | RatingVotes: 4 View profile of cyclops » |
Solutions
Solution by sherwinjaye, published 23. apr, 2007; download (492 kb), password: crackmes.de or browse.
sherwinjaye has rated this crackme as quite nice.
Discussion and comments
| unicorn 11. May 2006 | Nice checking function.Very eficcient i think. |
|---|---|
| indomit 15. May 2006 | I still work on it.... but it... long %) |
| sub7 15. May 2006 | Doesn't seem to break at a breakpoint. No confirmation of an invalid serial either... |
| Zaphod 21. May 2006 | sub7: Try setting a breakpoint at 401610 - that is before IsDebuggerPresent... |
| GEEK 22. May 2006 | 401610 is the start of the routine |
| Zaphod 22. May 2006 | GEEK: Yes, but it is not the entrypoint, and sub7 has probably tried setting breakpoints AFTER the debugger-check. |
| unicorn 02. Jun 2006 | The crackme is interesting . i thinks its doing some calculation over the given serials and checking whether the output is CyClOpS. It seems very wierd.Algo is complex, But as cyclops said the reverse algo can be writen in 2 minutes.I think the difficulty should be 2. The serials are in this format xx=xx=xx=xx=xx=xx=xx Here xx is a hex value and = is a seperator as it was not used in any calculations.(may be like this xx-xx-......) |
| m@rio_crk 02. Jun 2006 | It think this is quite easy, the values are constant in every 'loop' and you can make many different serials, for example: 00-00-00-00-00-00-00 00-00-00-00-00-00-00 00-00-00-00-00-00-00 00-00-00-00-00-00-00 43-79-43-6C-4F-70-53 ('CyClOpS') and I guess this 'mysterious' call (sub_4012B0) is for solving modular inversion ;) if the parametres were depending on the serial (not const) maybe this would be much more interesting crackme, anyway nice job cyclops! |
| cyclops Moderator 09. Jun 2006 | Thanx mario.Ur always Good. The solution u given is correct but its a straight away. Make a keygen and submit a solution. The routine 412B0 is used for finding the modular inverse. |
| sherwinjaye 16. Apr 2007 | Notice 00401A14 RDTSC, an anti-debug... :> |
You may leave your comment, thoughts and discuss this crackme with other reversers here.
Acting childish will not be tolerated.
HTML and such will be left as-is, so don't try.