No need for relays to do anything. But you could create something similar to the inbox.nostr.wine that authenticates the user before allowing them to download any 1059 that p-tags them. :) 

Those types of relays would be ideal for the 10050 event. 

Like with every other encryption in Nostr, if the attacker gets the private key, the attacker can decrypt all messages.  

 Ok I understand.  Thank you 🙏🙏🙏