Radio professionals - is it possible to know cell phone ID's of users within 100 meters using a device?

Question

I heard modern cell phones transmission pulses to the towers are encrypted and are only temporary ID's on a forum called halfbakery. Is that true? If I had a device that wanted to know the cell phone's permanent ID's, would I need the cellular company's cooperation with the devices?
Thanks

Answer 1

Old analog cell phones you could pick up ESNs and MINs through a process called snarfing. You could pick them futher than 100 meters depending on the cell phone's power and what you were using on the receiving end, especially the antenna and how high it was but the limit was still a couple miles. Since CDMA/TDMA/GSM/iDEN is all digital and encrypted, you wouldn't be able to accomplish the same without equipment only available to cell companies (plus their cooperation) and law enforcement. GSM has supposedly been cracked so I suppose it's possible to get them by other means...