I encrypt as much sensitive information in the database e.g. recipient email addresses, descriptions etc.

Someone suggested the idea of creating hashed aliases, that are generated and hashed on the client side so that even I do not know what they are, then incoming emails are compared against this hash to determine where to forward emails.

The only thing is there would probably need to be an additional column on the hashed alias that is client side encrypted so that the user can still view the actual alias in their dashboard.