zons's nvo keygenme #1
| Download keygenme.zip, 1 kb (password: crackmes.de) Browse contents of keygenme.zip Goal : Write a keygen.
Difficulty: 2 - Needs a little brain (or luck) | RatingVotes: 3 View profile of zons » |
Solutions
Solution by onepatop, published 25. aug, 2010; download (710 kb), password: crackmes.de or browse.
onepatop has rated this crackme as awesome.
Solution by freesoul, published 25. aug, 2010; download (6 kb), password: crackmes.de or browse.
freesoul has not rated this crackme yet.
Discussion and comments
| _ghandi_ 26. Mar 2010 | With a quick glance, i made a bruteforcer which spits out a valid key for my hwid but i guess you're looking more for an actual key generator? |
|---|---|
| Dionosis 26. Mar 2010 | @_ghandi> With a quick look I think a bruteforcer is the only realistic solution. |
| _ghandi_ 27. Mar 2010 | That was what i thought with the bit shifting, there are bits lost which cannot be recovered/reversed. |
| Numernia Moderator 31. Mar 2010 | I took a quick look and it seems like its quite depended on when you try register it, since it seems like you need a TIME_DWORD so the following results in <32 bit: (0x9F536D226B489AF8 * TIME_DWORD) (mod 2^64) |
| Numernia Moderator 31. Mar 2010 | Ok, this crackme is cool, and absolutely no bruteforce is needed. Once you get the structure of it is really easy. |
| BlackCode 04. Apr 2010 | lol it's bugged, try to insert 4294967295 (0xFFFFFFFF) |
| onepatop 24. Aug 2010 | I dont see anything easy bout this one, since it does like this: input_int^330345637 mod 4294967293 = result_int and then performs various checks on result_int. So to reverse input_int from result int, you will have to take 330345637's roots from result_int by modulo 9241 and 464773 with Adleman Manders Miller algorithm and then combine via Chinese remainder theorem(since 4294967293=9241×464773).Google search didnt reveal me any implementations of this kind of thing, so you probably will have to code algos yourself which is far beyond the scope of Level 2 crackme. |
| andrewl.us Moderator 24. Aug 2010 | keep searching: this type of equation (exponent mod a value with two factors) is very well known and requires no special algo implementations to invert |
| freesoul 24. Aug 2010 | OOh.. I'm working on this crackme I like it much :P |
| freesoul 25. Aug 2010 | lol andrewl my problem was to notice that's a simple modular exponentiation... ofc I know rivest.. :P |
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.