I can absolutely guarantee that the school generation would not naturally gravitate to the blockchain as a source for social interaction, since it's not (yet) running social media. I'm assuming TikTok (if it's common to post your own videos and not just consume?) or Snapchat (or whatever came next, that's probably old enough to be uncool by now I guess?)
EDIT: I just saw the suggestion that school administrators be identity providers for a crush-admission website. OK, now I'm _sure_ this must be satire. Well played.
Previous variant does not need any blockchain because you can just embed encrypted message to the web page similarly to the original hash variant (really it's the same as sending private message to your crush) but MPC variant probably needs blockhain because that's a perfect way to publicly precommit to something.
Note: there is still the possibility that you can precommit to "x is my crush" without x being your real crash to lure out if you are crush of x.
P.S. I think that's a good illustration of a service that can't be done without crypto and have similar properties.
Instead we can alter it and fix this problems: Bob will find out his crush’s public key, encrypt "you are my crush" message to it and post it with his own signature to public bulletin (blockchain can be good shelling point). When crush decrypts message they will see proper string, while everyone else will see gibberish.
- to solve problems with key distribution we can use "identity based encryption". it requires trusted third party (e.g. school administrators) but it solves problem for key generation of participants. With identity encryption bob can encrypt message to some canonical identity such as school email. Owner of that email can prove it’s identity to the third party and receive corresponding private key.