veneta's Crackme v22 (mini-psyho)
| Download Crackme_v22_(mini-psyho)_veneta.zip, 54 kb (password: crackmes.de) Browse contents of Crackme_v22_(mini-psyho)_veneta.zip litle simple crackme with some crypto ... a litle bit tricky (i think)
Difficulty: 3 - Getting harder | Send a message to veneta » View profile of veneta » |
Solutions
There are no solutions to this crackme yet. Have you solved it? Please write a tutorial and submit it here!
Discussion and comments
| Orphankill 20. Aug 2005 | Ok, I'm confused. I set a breakpoint on GetDlgItemTextA and I'm in. However, first you run all the letters of the name through some loop which does a whole bunch of stuff to each letter, then you run each letter of the entered serial through countless loops and then it goes on and on and on.... How much time do you think we have? Or maybe I missed something? A little nudge in the right direction would be nice :) |
|---|---|
| Knight 21. Aug 2005 | If i'm correct (and if i can post this here) this crackme uses ElGamal (or somethink like that). Just problem is that numbers are too big, to solve it. P.S. I think those loops u are talking about are SHA-1. |
| TQN 21. Aug 2005 | Yes, Knight. It is SHA-1, use Miracl library. |
| Tymon 21. Aug 2005 | ElGamal-128 + SHA1. You have to compute a and M. One question... This message 'how nice you've defeat..' means that serial is good or not ? coz there is the second message in crackme 'My Congrats Serial correct now you...'. What do you think ? |
| veneta Author 21. Aug 2005 | "My Congrats Serial correct now you..." is correct :) 1.ElGamal sign 2.surprise (my favourite board game ;) |
| veneta Author 21. Aug 2005 | i think it's sufficient answer :) |
| pdrill 30. Aug 2005 | This does not look like Elgamal and you dont need to solve DLP for it. |
| Knight 31. Aug 2005 | 3 people said that it is ElGamal (one of them is this crackme author) and u still think that it is not? :D |
| pdrill 31. Aug 2005 | Elgamal sig is: y^a * a^b == g^M where a and b is the sig and M is the message to be signed. This is not what is going on here. This crackme computs y^a * a^M == g^b. Set a=p-1 and you get y^a == 1 mod p. The order of p-1 mod p = 2 so a^M can have two solutions, 1 or p-1. This gives us a 50% chanse to set y^a * a ^M == 1 mod p for anny message M. Now, if you set b=p-1 you get g^b == 1 mod p. So,, does this looks like Elgamal? I can see you discuss the solution here so I hope I dont do anything wrong by posting this. This will only get you like 30% into the solution so there should be much more to solve for you. |
| pdrill 01. Sep 2005 | Finaly I got the correct messagebox :) Have you received a solution from anyone? |
| veneta Author 02. Sep 2005 | great work pdrill :) your solution is first and at the time only solution :) |
| Zuma555 05. Dec 2009 | I got it, and i submited a solution |
| jB_ 06. Dec 2009 | Zuma555: your solution does not include the 2nd part of the crackme. You only solved the crypto problem. |
| _pusher_ 06. Dec 2009 | jB: i checked quickly.. he seemed to have gotten the valid serials.. what did i miss ? :x |
| Zuma555 06. Dec 2009 | The only problem of this crackme was the crypto problem... What else was there to solve? |
| Zuma555 06. Dec 2009 | Btw Hello jB! ;) |
| jB_ 07. Dec 2009 | _pusher_: check the veneta message : "2.surprise (my favourite board game ;)" There is a reversi game in the crackme. The ElGamal signature is the easy part. |
| _pusher_ 07. Dec 2009 | right, think i have to reject your solution Zuma.. sorry :x Still.. i cant find any signs of any game at all :) |
| cyclops Moderator 07. Dec 2009 | "how nice you've defeat E****** s******** (heh you know what ;))" is only half part. If you have a complete solution it will show "My Congrats Serial correct now you..." ;) |
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.