Most protesters, activists, and journalists rely on their smartphones for organizing, sharing information, and documenting events, but using it can pose significant risks of surveillance by authorities. To maximize security and privacy at a protest, some advice includes bringing a secondary device rather than your primary smartphone, using strong screen locks, disabling biometric authentication, hiding notifications, protecting against surveillance, using encrypted messaging apps like Signal, staying prepared with backup power sources, securing and backing up your data, and being mindful of security practices during and after the event. Be cautious when posting photos online to avoid identifying others and always scrub photo metadata before sharing images to protect sensitive data.
https://www.privacyguides.org/articles/2025/01/23/activists-guide-securing-your-smartphone/