This week, we will introduce another way to secure your email: GnuPG. GnuPG (or the Gnu Privacy Guard) is an open source program for encryption and authentication that has a built in web-of-trust. If Alice “trusts” Bob’s key and Bob “trusts” Carol’s key, and Alice gets an email from Carol, she will be able to verify that Carol is indeed who she says she is, even if she has never met Alice. It is as if their mutual friend Bob had introduced them.
What if it is a business inquiry from a prospective customer? It would be totally legitimate, the email you most want to receive? I don't think this is a viable solution.