Hello and Welcome to PPCG!
Indeed, while PPCG is somewhat different from the main Stack Overflow site, there is a lot of information about questions that can be found in the Help pages, specifically the on-topic page and the pages this links to.
the on-topic page states:
All challenge questions on this site should have:
- A clear specification of what constitutes a correct submission, so that it is possible to indisputably decide whether an entry is valid or not. Test cases are highly encouraged.
- An objective primary winning criterion, so that it is possible to indisputably decide which entry should win.
These questions are surprisingly hard to write well. It is advisable to follow a standard template and to post them first and get feedback in the meta Sandbox so that flaws can be fixed before someone posts an answer which exploits them.
And then has links to a standard template found at Template For Challenges, as well as a sandbox where you can propose your challenge in a controlled environment and get feedback on it so it can be perfected.
The on-topic page also states:
However, if you have a general programming question, it should be asked on Stack Overflow or a different Stack Exchange site.
A lot of users on this site would consider your challenge, and especially the extra details you give, to be a general programming question and as such off-topic for this site, and I respectfully tend to agree with it. That is not to say that it is a poor challenge to propose. The challenge itself is something with clear definitions (given an input of a file name, return a truthy value if the file has only nullbytes, falsey otherwise), which lends itself well to this stack.
However, the intent of this site is for theoretical answers to theoretical challenges. It is not recommended to use any answer to any question on this site unless you understand what it does, and more importantly what it does not do. A lot of these answers sacrifice usability, performance, readability, security, portability or a combination of all these factors in return for minor improvements in their score. They can have a solution which takes 3 hours to complete for nontrivial results, or a solution that only works on a certain version of their language, or a solution that allows for remote code execution, or a solution that crashes your PC if the input is of the wrong type,... A solution can have any number of problems that are not apparent from a quick read.
In the end, this site is a series of competitions. And as with any competition, users will attempt to do any number of things within the rules of the challenge to win it. That's why it is important to fill the bigger loopholes before posting something.
I think in your situation, you chose the wrong site to ask this question on. A better solution would have been to choose a language yourself, write something that works, and then ask for advice on Code Review on how to improve it.
If you still want to participate in this community after these remarks and the ones you got on your question, you are welcome to post your challenge in the sandbox linked above. You should remove the elements where you say you want to use it yourself and try to adhere to the template in the other link. You can mention the part about the origin of the files (the dd copies) in the introduction to give some more clarity on the scope of the topic.
Lastly, don't be discouraged by this early setback. PPCG is the hardest ICT-related site on the entire network to create good questions for, and one of the hardest in general along with Worldbuilding, Puzzles and Skeptics. It is why existing users strongly urge new users to first post their question in the sandbox. We can indeed be a bit strict about our scope, but it is necessary to ensure a fair competition.