Wired: “A major groundswell of nationwide protests against the second Trump administration has arrived. If you’re going to join any protests, as is your right under the First Amendment, you need to think beyond your physical well-being to your digital security, too. The same surveillance apparatus that’s enabling the Trump administration’s raids of undocumented people and targeting of left-leaning activists will no doubt be out in full force on the streets. Two key elements of digital surveillance should be top of mind for protestors. One is the data that authorities could potentially obtain from your phone if you are detained, arrested, or they confiscate your device. The other is surveillance of all the identifying and revealing information that you produce when you attend a protest, which can include wireless interception of text messages and more, and tracking tools like license plate scanners and face recognition. You should be mindful of both. After all, police have already demonstrated their willingness to arrest and attack entirely peaceful protesters as well as journalists observing demonstrations. In that light, you should assume that any digital evidence that you were at or near a protest could be used against you. “The Trump administration is weaponizing essentially every lever of government to shut down, suppress, and curtail criticism of the administration and of the US government generally, and there have never been more surveillance toys available to law enforcement and to US government agencies,” says Evan Greer, the deputy director of the activist organization Fight for the Future, who also wrote a helpful X (then-Twitter) thread laying out digital security advice during the Black Lives Matter protests in the summer of 2020. “That said, there are a number of very simple, concrete things that you can do that make it exponentially more difficult for someone to intercept your communications, for a bad actor to ascertain your real-time location, or for the government to gain access to your private information.”

Your Phone: The most important decision to make before leaving home for a protest is whether to bring your phone—or what phone to bring. A smartphone broadcasts all sorts of identifying information; law enforcement can force your mobile carrier to cough up data about what cell towers your phone connects to and when. Police in the US have also been documented using so-called stingray devices, or IMSI catchers, that impersonate cell towers and trick all the phones in a certain area into connecting to them. This can give cops the individual mobile subscriber identity number of everyone at a protest at a given time, undermining the anonymity of entire crowds en masse. “The device in your pocket is definitely going to give off information that could be used to identify you,” says Harlo Holmes, director of digital security at the Freedom of the Press Foundation, a nonprofit press advocacy group. For that reason, Holmes suggests that protesters who want anonymity leave their primary phone at home altogether. If you do need a phone for coordination or as a way to call friends or a lawyer in case of an emergency, keep it off as much as possible to reduce the chances that it connects to a rogue cell tower or Wi-Fi hot spot being used by law enforcement for surveillance. Sort out logistics with friends in advance so you only need to turn your phone on if something goes awry. Or to be even more certain that your phone won’t be tracked, keep it in a Faraday bag that blocks all of its radio communications. Open the bag only when necessary. Holmes herself uses and recommends the Mission Darkness Faraday bag…”