Patent ID: 8544077

Claim:
A secure IP telephony system, the system comprising: a Cable Telephony Adapter (CTA) coupled to an IP telephony network and comprising a public/private key pair and a public key certificate signed by a certificate authority; a Key Distribution Center (KDC) coupled to the IP telephony network and configured to generate a ticket and session key to the CTA in response to a request from the CTA and distribute the session key to the CTA using public key encryption; and a signaling controller coupled to the IP telephony network and configured to receive the ticket in a set up request from the CTA and generate and distribute a symmetric sub-key to the CTA in response to the set up request in a reply message, wherein both the call set up request and the reply message are encrypted using the session key, wherein the ticket includes an identity of the CTA, an identity of the signaling controller, and an expiration time.