Research conducted by Orr Dunkelman, Nathan Keller and Adi Shamir in the Faculty of Mathematics and Computer Science at Israel's Weizmann Institute of Science has revealed that the security used on 3G calls could be 'hacked' within a couple of hours. The Israeli researchers focussed their attention on the A5/3 'KASUMI' encryption system, which is being introduced on many 3G mobile networks.
The news follows recent revelations that GSM security has also theoretically been broken.
[Sources: Summary at International Association for Crypologic Research; pdf document]