Wow, it's clear now that the project is going to fail for many other reasons, and that you really don't genuinely care about the privacy issues at all. > Well, did you see it was possible to simply print the QRCode ? You're just not getting my point. You continue to focus on one implementation choice (which itself is questionable) instead of addressing the fundamental issue of what data you're protecting and from whom, and how different choices might make solving the problem better. > In restaurant, people must give their personnal data on a sheet of paper, being highly unreliable and not efficient at all So don't do it that way. But neither should anyone just leap to the conclusion that a better solution is to write an app that throws everyone's data into the cloud. > Those are student too, if they misbehave, the bar is closed. And? If that's the only consequence for a massive data breach, just keep the bars closed. This rush to open things up without actually thinking through the procedures for doing so is making a lot of "higher education" look worse than the Pre-K school I attended. > we might use that to get some inspiration *Might*? If you haven't done the due diligence of keeping up on the developments of the domain you're supposed to be working in, I'm not sure how you even got hired to do the job. > But at one point we always need to rely on someone of trust That person should be the student who you expect to give up their data. Again, the fact that you don't see this and don't seem to have any desire to design such a system says to me that privacy isn't really a concern of yours. I have no doubt we'll be reading news stories about the inevitable debacle in this very subreddit. 92bc8847260f57a58f0a50fee5a4aa192dbc1db23aa3e3be2915235dbadd0f65