This article came in a right time for me. My team is assigned to think how to send "secure emails" to customers. The thing is that those emails contain documen

This article came in a right time for me. My team is assigned to think how to send "secure emails" to customers. The thing is that those emails contain documents as attachments which can contain names and social security numbers. Use case is that customer buy these documents from our website and they can be delivered to email. We already told that email is insecure by design to do things like that, but now I am thinking about other possibilities. Best I can come up with is encrypted attachment, but that's way too difficult for average customer to open it with public key. How have you handled situations like this?