gpg4win is a free and useful email security with an easy to understand and use graphical interface. gpg4win coordinates and implements an installer package of GnuPG, and GnuPG related software including handbooks for EMail and file encryption.
The configuration of X.509 root certificates is made simple by Gpg4win. Now, also inexperienced users can start using S/MIME out-of-the-box. Security aware system administrators will read the step by step instructions and define a systems-wide list of trusted X.509 root certificates.
Gpg4win supports using SmartCards for OpenPGP and S/MIME.