17 replies to this topic

[Icecube]

Challenge #14: Find the right key of this rude program.
Try it here.

Attached Files

•  challenge-14.zip   2.32KB   65 downloads

[AceInfinity]

I'm not quite done with challenge 13 but why are they all console applications? lol

[Icecube]

@ AceInfinity
Because I made those challenges myself with the help of the MinGW compiler on Linux (the irony ) and they are my first Windows programs. The filesize is also very small (around 4kb), so it should be easier to find the solution than in a GUI based application, which has a lot of clutter.

[Holmes.Sherlock]

Original post updated with a link to try out the challenge.

[Sha0]

Spoiler

Once modified to reveal the solution:

challenge-14 | md5

Yields that the MD5 hash of the answer is 924015BBE4ADF3781648AB98211A365D

[Holmes.Sherlock]

The MD5 hash of the answer is ....................

Nice idea to disclose the solution yet not announcing it publicly!!!

[Sha0]

Nice idea to disclose the solution yet not announcing it publicly!!!

A limitation being that without someone quoting it, it can be edited and if someone posts the answer, I could be accused of changing to to match their answer. However until someone posts the answer, anyone having the answer can know that I have the answer... A shared secret.

Hashes are nice for giving people confidence against tampering. I have a "card trick" program and usually ask Internet-based indulgers to take a hash of the program before starting. Even if they don't want the program at the moment, if they are impressed by it, they can verify that I didn't just customize the program to the parameters of their involvement, or that the program went out on the Internet to cheat. If they inspect the source code later on, they can have confidence that it was the same, throughout.

[Holmes.Sherlock]

Hashes are nice for giving people confidence against tampering. I have a "card trick" program and usually ask Internet-based indulgers to take a hash of the program before starting. Even if they don't want the program at the moment, if they are impressed by it, they can verify that I didn't just customize the program to the parameters of their involvement, or that the program went out on the Internet to cheat. If they inspect the source code later on, they can have confidence that it was the same, throughout.

It sounds the same way as "Digital Signature" works.

[AceInfinity]

Is the site down? I can't seem to access it, it comes up with the hosting page for me.

[Holmes.Sherlock]

Is the site down? I can't seem to access it, it comes up with the hosting page for me.

The reason is explained here.(http://reboot.pro/15...post__p__136875)

[Wonko the Sane]

Because I made those challenges myself with the help of the MinGW compiler on Linux (the irony ) and they are my first Windows programs.

As often happens, OT , but JFYI :
http://uncyclopedia....ki/Command_Line

(only a quick laugh, but I find it very well done)


Wonko

[Icecube]

@ AceInfinity
Link to challenge site updated in first post.

[Icecube]

Is there someone who was able to solve this challenge, besides Sha0?

[joakim]

I had a try last night but failed. Do you have a clue to give, like how many instructions to change etc?

[Icecube]

I had a try last night but failed. Do you have a clue to give, like how many instructions to change etc?

Looking at the executable with a hexeditor first might reveal something interesting.

IDA pro might be handy too. The free version can be found at:
http://www.hex-rays....ownfreeware.htm

[joakim]

So I had it right almost from the start, as I compared against the wrong key. Misinterpreted Sha0's statement:

Yields that the MD5 hash of the answer is 924015BBE4ADF3781648AB98211A365D

To be the hash of the key (and not the executable). I never tried the key online, just compared against the wrong md5..

IDA is definetely good. Love it.

[Holmes.Sherlock]

@joakim
Have you tried your solution in the challenge site? If not, then please login there with your reboot username & try out the challenge to help us keep track of the participants who have successfully solved the challenge.

[joakim]

Yes I did, and it was correct.