If your goal is to attract people who genuinely enjoy solving exceptionally difficult programming and reverse-engineering problems, the best communities depend on what kind of challenge you're building.
Here's where I'd look:
-
CTFtime (Capture the Flag community)
If your challenge is anything like Mercury Rising—cryptography, binary analysis, steganography, obscure protocols, or reverse engineering—the CTF community is probably your best audience.
- Thousands of experienced solvers.
- Teams regularly spend dozens of hours on a single challenge.
- Difficult challenges are expected rather than discouraged.
-
Project Euler
- Ideal if it's algorithmic and mathematical.
- Less suitable for reverse engineering or puzzles.
- People enjoy problems that require deep insight rather than brute force.
-
Codeforces
- Excellent for advanced algorithms.
- The top users are among the strongest competitive programmers.
- Challenges generally need to fit contest formats and time limits.
-
Hack The Box
- Great if your puzzle involves exploitation, reversing, networking, or cryptography.
- Users actively look for extremely difficult machines and challenges.
-
Root Me
- Another community that enjoys difficult security-oriented puzzles.
-
r/programming and r/coding
- Good for visibility.
- Not necessarily where the strongest puzzle solvers congregate.
-
r/reverseengineering
- Fantastic if it involves binary analysis or reverse engineering.
- Many professionals browse there.
-
Stack Exchange Code Golf
- More puzzle-oriented than hacking-oriented.
- Users enjoy unusual programming problems.
-
Discord CTF communities
- Many elite reverse engineers spend time in CTF Discord servers.
- Word spreads quickly if the puzzle is genuinely interesting.
If you want "Mercury Rising" difficulty...
The fictional "Mercury Rising" puzzle is essentially a mythically difficult code that only a prodigy could solve. In reality, the closest modern equivalents are:
- Alternate Reality Games (ARGs)
- Cicada 3301-style puzzles
- DEF CON CTF finals
- PlaidCTF
- Google CTF
- HITCON CTF
These often require multiple disciplines:
- reverse engineering
- cryptography
- programming
- networking
- mathematics
- OS internals
- pattern recognition
- sometimes hardware knowledge
A single solve may take an expert team many days.
A challenge that gets attention
The hardest challenges aren't just difficult—they're layered. For example:
- Stage 1: Discover a hidden protocol.
- Stage 2: Reverse a custom virtual machine.
- Stage 3: Recover an encrypted state machine.
- Stage 4: Infer an undocumented algorithm.
- Stage 5: Write code to defeat that algorithm.
- Final stage: Extract the hidden flag or message.
Each stage teaches something new rather than simply increasing computational effort.
My recommendation
If your goal is to see whether anyone in the world can crack it, I'd release it as a public CTF-style challenge, announce it in CTF communities (such as CTFtime listings and relevant Discord servers), and share it in reverse-engineering communities. Those audiences actively seek out problems that require hours or even days of sustained effort, and if your challenge is original and well-designed, it has a good chance of attracting skilled solvers.
