obnoxious's Optimise
| Download optimise.zip, 5 kb (password: crackmes.de) Browse contents of optimise.zip Its been long since i last put a crackme so have fun cracking this one.
Difficulty: 2 - Needs a little brain (or luck) | RatingWaiting for at least 3 votes View profile of obnoxious » |
Solutions
Solution by sghctoma, published 05. feb, 2009; download (22 kb), password: crackmes.de or browse.
sghctoma has not rated this crackme yet.
Discussion and comments
| obnoxious Author 01. Feb 2009 | I forgot to mention "No patching too" Have Fun!!!! |
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| sghctoma 02. Feb 2009 | hi! thx for this crackme, it was fun to solve it.. I have just submitted a solution, I hope it gets accepted :) this crackme made me blow the dust off my discrete mathematics books, because I became curious about Diophantine equations.. |
| zapline 03. Feb 2009 | 1 “h”“ p”“ x” 13*8 14*8 15*8 2 14*7 15*7 16*7 17*7 3 17-20 *6 4 20-24 *5 5 25-20 *4 6 33-40 *3 7 49-61 *2 8 97-122 *1 like： xwrdxoze ppxipofx pbldhlhx pplilxbq xplnxllo xwrspctp |
| indomit 09. Feb 2009 | if ((((Convert.ToInt32(str.Substring(5, 1)) * num) + (Convert.ToInt32(str.Substring(6, 1)) * num2)) + (Convert.ToInt32(str.Substring(8, 1)) * num3)) <= Convert.ToInt32(str.Substring(9, 4))) { num5++; } I think that the author wanted to indicate the 6th, 7th, 8th digits rather than 5, 6, 8. because the fifth digit is 0. Or not? :) |
| indomit 09. Feb 2009 | And, Solution by sghctoma is incorrect. Keygen not working. I think its because the last equations value is not 6001. 0x17 = 23, and Convert.ToInt32(str.Substring(0x17, 4))) = Convert.ToInt32(str.Substring(23, 4))) = 2400 |
| sghctoma 09. Feb 2009 | OMG, you're correct, I have messed it up.. I guess I was just lucky, and always got values that are good for the last inequality as well while testing the keygen.. thanks for pointing this mistake out.. |
| obnoxious Author 13. Feb 2009 | Its cool. A bit of miss coding :P.... Keygen will work for some keys generated...Nice solution sghctoma. |
| obnoxious Author 13. Feb 2009 | @indomit that equation is just that way :) "optimisation by linear programming problem - simplex method" :) |
| indomit 13. Feb 2009 | I just see that 7th symbol of string str is never used... That's confused me :) |
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