A method and system for providing secure access to a device initiating communications using a peer-to-peer signaling protocol, such as a SIP or H.323. In a device registration phase, the device contacts a secure access server, and authenticates to the secure access server by providing an identification, such as its factory ID. The secure access server then issues a device ID and private key to the authenticated device. A client can then initiate a further communication session and be authenticated by the secure access server. The secure access server returns the device identification and the device's public key to the client. The client and device can then perform a symmetrical key exchange for their current communication session, and can communicate with appropriate encryption. The device's private key can be set to expire after one or more uses.