This weekend I took part in an security challenge. I had great fun doing it but i found a huge gap in my knowledge that I'm really keen to fill and hope someone here can help get me pointing in the right direction.

Midway into the challenge I discovered 2 files that appeared to contain encrypted data, but i could find no clues at to the encryption method or a key that may unlock them.

On the assumption that I'd not just overlooked this information, how could i of started to extract the information from the data? I'd be happy to share the files somewhere if someone can recommend a place to upload?


closed as off-topic by Xander, Steve, Mark, TildalWave, AJ Henderson Aug 19 '14 at 15:18

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Unless it is an insecure cipher, you won't be able to know which algorithm was used. That's what confusion/diffusion is all about.

From my experience with such challenges, I'd say you're missing something. Maybe there's a key somewhere, maybe you get your hands on some source code, etc.

  • As for a key, the only thing i did find that 'could' have been related was the string 'rand1872342hhaa' – bulldog5046 Aug 18 '14 at 14:13

There's too few information here. Not knowing the full challenge, it's very hard to suggest what they expected you to do.

Maybe you were supposed to notice the encryption method and break it, perhaps the key was given somewhere else, you may even be expected to break or guess it (eg. if it was 1234).

I suggest you wait for a summary of the challenge by other participants (sometimes even by the organization) explaining the steps they tool. One man's CTF procedure is not always suitable for other, but should work as a starting point in case you face something similar at some point.

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