The big brother is always listening, no matter how quietly you speak. In case of cell phones, considering the encryption technology used by most of the GSM operators, it is like speaking on a public addressing system.
To bring this to the notice of the concerned bodies, Karsten Nohl started the most ambitious attempt to compromise the GSM phone system, which is used by over 3 billion people around the world. Others have cracked the A5/1encryption technology used in GSM before, but their results have remained secret. However, Nohl intended to go one big step further and planned to make the keys available to everyone on the Internet.
At the second day of the Chaos Communication Congress, he informed that he had cracked the code and published it for others to read and review. The GSM Association doesn't seem to be very happy with this development. According to NY Times, a GSM spokesperson told the newspaper that Nohl's activity is illegal in the UK and the United stated and that it was not in good faith -- " To do this while supposedly being concerned about privacy is beyond me.”