German hacker cracks GSM encryption

Karsten Nohl, working with other experts, has spent the past five months cracking the algorithm used to encrypt calls using GSM technology.

GSM is the most popular standard for mobile networks around the world.

The work could allow anyone - including criminals - to eavesdrop on private phone conversations.

Mr Nohl told the Chaos Communication Congress in Berlin that the work showed that GSM security was "inadequate".

"We are trying to inform people about this widespread vulnerability," he told BBC News.

"We hope to create some additional pressure and demand from customers for better encryption."

(...) Mr Nohl told the BBC that he had consulted with lawyers before publication and believed the work was "legal".

(...) Mr Nohl, working with a "few dozen" other people, claims to have published material that would crack the A5/1 algorithm, a 22-year-old code used by many carriers.

The code is designed to prevent phone calls from being intercepted by forcing mobile phones and base stations to rapidly change radio frequencies over a spectrum of 80 channels.