I have a customer that needs to have their email recipients verify their identity before opening an email with sensitive material in it. For example if I send an email to jsmith@domain.com I need something to pop up and ask "what are the last four digits of your SSN", or something like that, before allowing them to open the email. In other words I need to verify that jsmith is John Smith and not Joe Smith. Can this be done with Exchange or Office 365? I know there are 3rd party services out there, but I would like to keep it to either Exchange or Office365.
Thanks in advance!