We need to encrypt email btween a customer of ours and us. I have been
looking at options. We are footing the bill. It will begin with a single
address here and one customer with three email addressses. We will expand
this to over 20 customers if things go well. This will get expensive so we
want to choose the right solution. We want something that will be cross
platform and non-intrusive for the customer, not to mention easy to set up.

Any opinions?

Thanks in advance for your time!