About the Author
David Endler is the Director of Security Research for TippingPoint, a division of 3Com. Previously, he performed security research for Xerox Corporation, the NSA, and MIT. Endler is also the chairman and founder of the Voice over IP Security Alliance.
Mark Collier is CTO for SecureLogix Corporation. He is an expert author and frequent presenter on the topic of VoIP security. Collier is also a founding member of the Voice over IP Security Alliance.