I am an author and regularly forward confidential copies of my work to my publisher/agent/friends. Obviously I don't want these copies leaking to the public. I searched online for a way to encrypt these email attachments and ensure that the recipient can't print, forward, or copy the attachment. I found a couple of software companies that do this, but they only seem to work for windows operating systems. Does anyone know of a security email system that would work for macs too? Thanks!