3G uses the KASUMI or A5&#x2F;3 cipher which was shown to be easily broken in in 2010 (two hours on a PC via a related key attack):<p>&gt;we have actually simulated the attack in less than two hours on a single PC, and experimentally verified its correctness and complexity. Interestingly, neither our technique nor any other published attack can break MISTY in less than the $2^{128}$ complexity of exhaustive search, which indicates that the changes made by the GSM Association in moving from MISTY to KASUMI resulted in a much weaker cryptosystem. - <a href="http:&#x2F;&#x2F;eprint.iacr.org&#x2F;2010&#x2F;013" rel="nofollow">http:&#x2F;&#x2F;eprint.iacr.org&#x2F;2010&#x2F;013</a><p>This is actually far worse than cell site simulation because it is a passive attack and so is totally undetectable. You could just setup recording equipment, hide them in a van and start decrypting conversations. Given how much weaker KASUMI is from MISTY is seems possible this was a backdoor engineered by an intelligence agency. If so, it certainly tells the lie to NOBUS (no one but us).<p>Odd how the GSM association always generates breakable ciphers.