Patent ID: 7570765

Claim:
A method comprising: monitoring negotiation between a first Voice-over-Internet-Protocol (VoIP) device and a second VoIP device during setup of a call between the first and the second VoIP devices; determining whether the first VoIP device is Secure Real-time Transport Protocol (SRTP)-capable and whether the second VoIP device is SRTP-capable; and performing SRTP-on-the-fly on a Real-time Transport Protocol (RTP) stream transmitted between the first and the second VoIP devices to make the call secure if the first VoIP device is not SRTP-capable and the second VoIP device is SRTP-capable, wherein performing SRTP-on-the-fly on the RTP stream comprises encrypting the RTP stream using a firewall on the side of the first VoIP device as the RTP stream passes through the firewall if the first VoIP device sends the RTP stream to the second VoIP device, and sending the encrypted RTP stream from the firewall to the second VoIP device.