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+1 to vortex. I participate often in CTF competitions and it's my go to recommendation for serious people looking to get more involved. Most of the early stages

+1 to vortex. I participate often in CTF competitions and it's my go to recommendation for serious people looking to get more involved. Most of the early stages are great because they are no nonsense - they give you the papers explaining the solution, and just ask you to do the work of understanding and implementing them. Stage 16 is one of my favorite challenges all time. It took me weeks to solve and the solution is very impressive. I've been stuck for the last few years on stage 23. Unlike the rest of the challenges it is a stenography level, and I'm not convinced that it is still solvable today.

philipodonnell 8y ago
> I'm not convinced that it is still solvable today. This sounds fascinating since progress does not tend to work that way. What is it about this problem that leads you to think it was solvable in the past but no longer?
- jgeralnik 8y ago
  The challenge in question is just a jpg of the logo of ruxcon 2004. The password for the next level is presumably steganographically encoded in it. The challenge is much easier (and perhaps only possible) given the original image, but the logo is no longer on the internet. After scouring web archive and using all Google fu at my command I found some instances of the image but all in different sizes/dimensions. The name of the level is "the properties of a mirror" which hints that you need to find a mirror of the original site in order to solve the level, and I think that the mirrors are no longer online. Note for anyone unfamiliar that this level is not at all representative of vortex - all the other levels are all hard core exploit implementation and not stego challenges. In general I don't like stego because I feel that it is more of "try to guess what I'm thinking" than solving interesting challenges.
  - philipodonnell 8y ago
    > The name of the level is "the properties of a mirror" which hints that you need to find a mirror of the original site in order to solve the level, and I think that the mirrors are no longer online. I would assume that if this were the case someone who has already completed that level could check if where they found it was still up? Perhaps this is not the interpretation of the level name that the writers had in mind?
    - jgeralnik 8y ago
      The challenges are years old and not actively maintained. Until this thread I haven't seen any people who passed level 12 or so

philipodonnell 8y ago

> I'm not convinced that it is still solvable today. This sounds fascinating since progress does not tend to work that way. What is it about this problem that leads you to think it was solvable in the past but no longer?

jgeralnik 8y ago
The challenge in question is just a jpg of the logo of ruxcon 2004. The password for the next level is presumably steganographically encoded in it. The challenge is much easier (and perhaps only possible) given the original image, but the logo is no longer on the internet. After scouring web archive and using all Google fu at my command I found some instances of the image but all in different sizes/dimensions. The name of the level is "the properties of a mirror" which hints that you need to find a mirror of the original site in order to solve the level, and I think that the mirrors are no longer online. Note for anyone unfamiliar that this level is not at all representative of vortex - all the other levels are all hard core exploit implementation and not stego challenges. In general I don't like stego because I feel that it is more of "try to guess what I'm thinking" than solving interesting challenges.
- philipodonnell 8y ago
  > The name of the level is "the properties of a mirror" which hints that you need to find a mirror of the original site in order to solve the level, and I think that the mirrors are no longer online. I would assume that if this were the case someone who has already completed that level could check if where they found it was still up? Perhaps this is not the interpretation of the level name that the writers had in mind?
  - jgeralnik 8y ago
    The challenges are years old and not actively maintained. Until this thread I haven't seen any people who passed level 12 or so