Protected Industries uses and recommends the use of PGP encryption for sensitive communications over email. The open source port of GPG is GPG. Both encryption suites produce data which is, for the sake of this topic, interchangable. Because of this, in the industry, the terms GPG and PGP are often used interchangably.
This page provides links and instructions to use the free, open-source GPG so our clients can get up and running to communicate with us.
Windows
For Outlook under Wndows, we recommend using the gpg4win suite. There are decent instructions on how to install and use the package at GPG For Novices.
OSX
If you are using Mail.app, Apple's default email cilent, this page provides instructions on how to download and use GPGMail with Mail.app. This is what Protected Industries uses, and we are very happy with the utility.
If you are using Mozilla's Thunderbird mail client, we have had success with the Enigmail package in the past.
*NIX
When operating in UNIX-like environments, we usually use gpg from the command line. If anybody has interest in this page covering GUI GPG interfaces, let us know and we will add the information.