Look at Atabok (Score 1)

I've worked for several security technology companies including RSA and Sony/BMG (yup, they developed DRM software, so they qualify), and have found Atabok has excellent technology and solutions. Standards-based: x.509 certs, managed PKI, 256 bit AES, protected in memory, integrates with Outlook, Notes and Acrobat, and has clients which run on Linux/Unix/Mac. It can be hosted or brought in-house. The client experience is pretty close to seamless and, unlike PGP, easy to install and manage for an organization. They even offer DRM for office/PDF docs (view/print/combust), all in one integrated solution. What's more, the people that work there are great, esp. their chief scientist [IMO].