I am currently searching for the best application or service to provide end to end security for delivering encrypted emails from one company to another accross the Internet. I need the solutions to provide Smime, PGP, TLS, SSL, etc.
My goal is to some how have the app or user decide if the email needs to be encrypted, then apply a cert which can be maintained. The email then sent to the recpt. who then decryptes the message using either of these options. I hope that the gateway can negotiation which type to use with the other gateway/exchange server.
If the negotiation fails then just send an email with a link back to an SSL web server so the email is still encrypted. This needs to work for all companys including people with hotmail, yahoo, etc. accounts.
I am currently looking at:
In this exact order
Does anyone have experience with these products or trying to secure the company external email?