I dont email anything anymore, I use a secure portal for people to upload to, I still send copies by regular US Mail, unmasked, if the SSA can send out the actual SS card by regular US Mail, I can send unmasked copies to people!!   

I tell people over and over ,dont email me anything with your confidential info  on it, but we've always got those that dont read or listen, so thats on them!  I scan it with my AV, then print it and delete the email.