ZeroCoder's crackme #12
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Difficulty: 6 - Hard, for very professionals only | RatingWaiting for at least 3 votes View profile of ZeroCoder » |
Solutions
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Discussion and comments
| TaGaDaPaF! 03. May 2005 | Hello :) I've tried to bruteforce the algo with numbers and a dictionnary, no luck. Is there anything to do beside bruteforcing ? (it would take years...) |
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| Sinclaire 03. May 2005 | Well, judging from the rating the autour has set for it, therefore bf it is not very applicable, and do you think bf was the way ?, then i think you misunderstood the purpose of the challense, break the protection by explaining how it works, not just to get a serial or whatever it wants, i suggest you analyse it more (i.e. static analysis), and good luck. |
| TaGaDaPaF! 03. May 2005 | Well... I know how the algo works, but i can't figure out how to reverse it. It compute a hash from the name, therefore it seems impossible to reverse it. I will try some other way to break it an other day :p |
| ZeroCoder Author 04. May 2005 | hi crackers-brothers. why you won't use random bruteforce attak? tips: true password of 10chars |
| TaGaDaPaF! 04. May 2005 | Heh ... bruteforcing... Current Serial: 0QB6YmyrNC Rate: 415910 Serial/sec Current Serial: Ab3QBCgH81 Rate: 417196 Serial/sec It will take me 60000years for the worst case :) maybe i will be very lucky and have it in 2 years ! I feel stupid :) |
| cronos 17. May 2005 | perhaps there is a shortcut, like in zerocoders #11 which had a 16-byte key ? |
| cronos 18. May 2005 | well, i had a look. i don't see any shortcuts at the moment. i tried a bruteforce using the output of jtr with a big set of rules and didn't manage to crack it. my general bruteforcer for this is a lot slower than yours (even taking an early exit strategy). i was hoping to see some correlation between input bits and output bits and use a more intelligent approach but i can't find one.... |
| TaGaDaPaF! 18. May 2005 | This was my idea: the serial length is 10 chars, the function procuce a hash of 10 bits. I start with a choosen serial, hash it, generate a serial from the hash (and this is *very* fast), hash it, ... and so on. I log a serial every 60secs in a file and an other program that i launch manually verifies if the main program has not gone into a loop. I've stopped because it looked endless... maybe there is something smart to notice ! ( oh ! maybe not... ) I will look it again in a while, i will have a fresh look on it ;) |
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