I drove down to Palo Alto today and had lunch with three of the co-founders of Voltage Security.  Smart guys.  They are a well-knitted team with personalities and perspectives that complement each other well.  I liked that.

Three Volts: Rishi Kacker, Guido Appenzeller, and Matt Pauker

This is how their key product, SecureMail works:

Alice at Company A would like to send her customer, Bob at Company B, a sensitive email that must be secure for compliance reasons. She uses Voltage SecureMail to send the secure email to Bob.

Alice sends a secure email to Bob
After Alice composes the email, she simply hits the Send Secure button, which automatically secures the email, along with any attachments, using Bob’s email address “bob@b.com”.

Voltage SecureMail does not require pre-enrollment of users to receive secure email; even if Bob has never previously communicated with Alice or has never used Voltage SecureMail, he is still able to receive secure email from Alice.

Bob receives the secure email
The first time Bob receives the secure email on his laptop, Bob clicks on a link in the message header and downloads the Voltage SecureMail client. He then proceeds to enroll and authenticate to Company A’s SecurePolicy Suite. The method used to authenticate Bob is completely flexible to the requirements of the enterprise.

Bob decrypts and views the email message
Upon completion of proper authentication, the SecurePolicy Suite will present Bob with his private key to read the sensitive email. Alice and Bob can now communicate securely with Voltage SecureMail.

With his private key downloaded to his laptop, Bob can decrypt and view his received secure email even when he is offline on an airplane. Bob can even read his secure email at a business center using Voltage SecureMail's transparent roaming capabilities.

As you can see, Voltage neatly sidesteps the need to build expensive PKI infrastructures.  Although their biggest weakness is the need to install software on the client, the problem is offset to some degree by the viral aspect of the solution:

Alice infects Bob by sending an encrypted mail that prompts Bob to download and install Voltage client in order to read the encrypted message.  With client installed, Bob can send encrypted mail to others as well, infecting them in the process.

They chose a good name for their company because another way to look at it is electricity (security) flowing and spreading across the Internet via e-mail, charging everyone in the process with higher security.  Voltage Security sounds a whole lot better than Viral Security, no?  <g>

Update #1: I changed "three co-founders" to "three of the co-founders" after reading Scott's post.  There are four co-founders of Voltage as you can see here.