We've had this idea floating around for ages, but I can't find an existing issue, so creating one that we can add to the DAG.

Zcash shielded transactions by default have sender anonymity: the recipient learns nothing about the sender.

Some wallets have chosen to optionally include "reply-to" addresses as text in a recipient's memo field, giving the recipient a pathway to send funds back to the sender (effectively establishing a payment channel). However, there is nothing proving either control by the sender of the address itself, or that this address was at all related to the funds spent in the transaction.

TODO: Add examples of other protocols that benefit from this.