I have an interesting use case for permanently storing an arbitrary hash string somewhere "reliable" publicly and, very important, with a trustworthy timestamp. For me, this sounds like a case for a blockchain application. As I feel a diffuse kind of sympathy for the Cardano project, i thought "why not start here". Let me explain a bit:
The idea is to create a strong hash (SHA2-256 or the like) of arbitrary data (text files, photos, combinations of these, ...). This part is easy. I don't need a blockchain for that and there are many well established standards for doing this. But now I also want to be able to reliably prove, forever, 'til eternity, that this specific hash existed at a certain time.
My first thought was, well, couldn't I just push this hash to a blockchain somehow? I mean, each transaction has a public timestamp that can't be messed with, right? Does Cardano allow for appending metadata like an arbitrary hash string to a transaction? Should I mint an NFT which holds this data? Then again, wouldn't that be overkill for my use case? What are the technical possibilities I could try to work with, here?
I am a developer, but my insights in blockchain technology are quite rudimentary. So I hope that someone can help me out by pointing me in the right direction. Thank you in advance!