We have this. Ecash tokens that are encoded to be received by an npub. This way you can broadcast it over a public channel and it cannot be redeemed at the mint without a signature from the recipient's private key. This way the token can even be left in long-term storage and there is no way it can be stolen because not only does it need the recipient to sign a spend authorization, once its redeemed the token is worthless. This means you can literally print a qr code on a piece of paper, send it through the mail, include it in the back of a book, put it on a billboard and it is still safe from theft.