Patent ID: 8539564

Claim:
A method of establishing keys for at least partially securing media plane data exchanged between first and second end points via respective first and second media plane network nodes, the method comprising: sending session set-up signalling from said first end point towards said second end point, said session set-up signalling including a session key generated by said first end point; intercepting said set-up signalling at a first signalling plane network node and determining whether a signalling plane key has already been established for securing the signalling plane between said first end point and said first signalling plane network node; if the signalling plane key has already been established, then deriving from the signalling plane key a media plane key, and sending the media plane key to said first media plane network node for securing the media plane between said first end point and said first media plane network node; and if the signalling plane key has not already been established, then deriving from said session key an alternative media plane key, and sending the alternative media plane key to said first media plane network node for securing the media plane between said first end point and said first media plane network node.