Who is really listening?
September 22, 2014 8:32 AM Subscribe
An international mobile subscriber identity (IMSI) is a unique number, usually fifteen digits, associated with Global System for Mobile Communications (GSM) and Universal Mobile Telecommunications System (UMTS) network mobile phone users. An IMSI catcher is a device, used by the NSA drone program, the police, criminals, Chinese spammers and spies all around Washington DC and the world to spoof the identity of a GSM cell tower and intercept cellular voice and data communication. They come in all sizes and flavors, from tiny or body-worn professional surveillance devices, to easy to order off the shelf solutions, to Chinese DIY (links in Chinese) and have spawned efforts to retaliate with an IMSI-catcher-catcher. IMSI-catcher technology has become increasingly widespread, with far-reaching constitutional and technical implications.
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