This is unsurprising but it's now confirmed via search warrant documentation that ICE is using a cell site simulator/IMSI catcher described as a Hailstorm or a Stingray http://www.detroitnews.com/story/news/local/detroit-city/2017/05/18/cell-sno... to surveil and prosecute undocumented immigrants. Journalists and ACLU https://www.aclu.org/news/aclu-seeks-documents-ices-use-cell-phone-trackers (probably others) are making FOIA requests and will likely need to sue. Cell site simulators were kept mostly secret for about a decade after introduction for domestic use and local departments were required by FBI or manufacturer to conceal their use from judges and defense counsels. https://gizmodo.com/ice-agents-are-using-stingray-surveillance-tech-to-capt-... In some cases, such as St. Louis, prosecutors dropped charges against defendants who had cell site simulators used against them. Cell site simulators are *strongly* suspected of being used against protesters in Chicago, St. Louis/Ferguson, and Minneapolis, and known to have been used in Standing Rock http://geekswobounds.org/sites/default/files/Security%20at%20Resistance%20Ca... http://gwob.org/security-at-resistance-camps-lessons-from-standing-rock/ , including delivering malware payloads. ICE joins dozens of state and local law enforcement agencies, and FBI, USMS, ATF, DEA, IRS, FCC, NSA, and various military entities. https://www.aclu.org/map/stingray-tracking-devices-whos-got-them https://theintercept.com/surveillance-catalogue/ http://graphics.wsj.com/surveillance-catalog/ Given the military-industrial-surveillance complex and that a moderately skilled hacker can construct one, they are no doubt in use by private security and intelligence agencies, as well, with G4S and Academi/Xe/Blackwater certainly coming to mind. So use the crypto (Signal or others), to the extent that it protects content in transit. Some cell site simulators' imitation convinces phones to decrypt the carrier's encryption. If a device can be infected then even measures like Signal may be circumvented. We need more privacy-by-design and hardened devices.