I would HIGHLY recommend reading up on the keybase architecture. They designed device key system for real time chat that is e2e secure. https://book.keybase.io/security

A property of ec keys is deriving new keys that can be determined to be “on curve.” bitcoin has some BIPs that derive single use keys for every transaction connected to a wallet. And be derived as either public or private chains. https://qvault.io/security/bip-32-watch-only-wallets/