we have a need for encrypting emails that are sent from our exchange 2003 server so that outside recipients must somehow decrypt the emails to read the contents. so far the only thing I have seen that will do this is a hosted email service where the recipients would need to create an account and log in to retrieve their emails.
while it has the advantage of notifying the recipient that they have a new encrypted message, this is essentially the same as me encrypting internal emails and then creating an account for the external recipient and having them log in to retrieve their email. of course it would require a lot less effort on my part to use the hosted service but would include a monthly price tag and significant startup fees as well.
so I'm looking for other options, preferably something that is made to work with exchange 2003... any suggestions?