Mobile phone users are being encouraged to find out if operators are doing enough to keep their calls secret.

Security researchers have released tools that, they say, make it easy to see what security systems operators use to stop eavesdropping.

The researchers want to expose those operators that have not updated security systems to prevent others listening in.

The tools are based on an attack first demonstrated in late 2009.

To read this BBC News report in full, see:
www.bbc.co.uk/news/technology-10731612