(Telecompaper) Gemalto has completed its investigation into the alleged hacking of Sim card encryption keys by GCHQ and the NSA in 2010 and 2011, finding that the operation probably did happen. The company said the attack only breached its office networks and therefore could not have resulted in a massive theft of encryption keys. The operation aimed to intercept the keys as they were exchanged between mobile operators and suppliers, but by 2010, Gemalto had already deployed a secure transfer system with customers, that could only have led to theft in rare exceptions. If a Sim encryption key was stolen, it would only have allowed the intelligence services to spy on communications on 2G mobile networks, because 3G and 4G networks are not vulnerable to this sort of attack, according to Gemalto, which added that none of its other products was impacted by the attack. It recommended the systematic encryption of data when stored and in transit, as well as the use of the latest Sim cards and customised algorithms for each operator.