Have you ever accidentally emailed a sensitive document to the wrong person, or lost a flash drive containing important data? You know you should have used encryption, but you forgot, or you felt it would be too much trouble. It's a terrible feeling, and one that the free HP Trust Circles encryption tool is designed to help avoid by making encryption simple, seamless, and automatic. Members of a "trust circle" can transparently view and modify any documents belonging to the group; to anybody else, they're gibberish.

There are actually several versions of this product. The Standard edition comes pre-installed on some HP computers, and it's also available as a free download on any HP computer. With this edition, you can create up to five trust circles, each with up to five members (we'll get into what that means shortly). If your computer isn't an HP, you can download the Basic edition, which gets you one trust circle with up to five members. For this review, I used the Basic edition of Trust Circles.

From either of these editions, you can upgrade to the Pro edition, which lets you create unlimited trust circles and invite unlimited members. Upgrading from the Standard (HP-only) edition costs $19.95, while upgrading from Basic costs $29.95. You'll want to try out the free edition first, to get a feel for how it works.

Getting Started
HP Trust Circles needs outgoing email access for when it sends invitations to new members. If you're an Outlook user, just use the convenient Outlook add-in. If not, you need to give the program your email address and password. For Gmail and other common providers, the program automatically configures itself for sending mail. If you're using a different provider, you'll need to give it your SMTP server address.

I ran into one minor snag setting up HP Trust Circles. Initially I tried installing it on a Windows Vista system, since that system holds my day-to-day Outlook installation. I overlooked the fact that the product only supports Windows 7 and Windows 8; I wish the installer had simply warned me.

Simple Authentication
Logging in to HP Trust Circles is simple—you just use your Windows account password. In a business setting, you can use an Active Directory or domain account. If you haven't password-protected your Windows account, do so before installing the product. If your Windows account password is weak, consider upgrading it to something stronger, since your Windows password is now also your encryption password.

By default, HP Trust Circles locks after 15 minutes, requiring re-entry of your password. In truth, there's no need to leave it running when you're not actively managing your circles. I'd recommend cranking this setting down to five minutes.

Note that if you walk away from your desk without logging off, a corporate spy could read your protected documents and copy their contents. Get in the habit of hitting Windows-L to lock the desktop any time you step away. It's a good practice whether you're using Trust Circles or not.