How to do it:

Your security steps depend on your situation. Crossing a U.S. border (or sometimes being within proximity of one) reduce your legal protections. If you do not want to hand over an unlocked phone, consider buying a cheap travel phone. They can hold on to a phone you won’t unlock for an extended period. Within our borders you (ostensibly) have more rights, but courts have ruled police can open phones that use facial or thumbprint access by force. The first thing you should do is remove that access and set a passcode instead.

Next steps include using a safer messaging app like Signal, and learning about your phone’s security settings. Here are resources to get you started:

• iPhone privacy: https://ssd.eff.org/module/how-to-get-to-know-iphone-privacy-and-security-settings
• Android privacy: https://ssd.eff.org/module/how-to-get-to-know-android-privacy-and-security-settings
• Guide to Signal: https://ssd.eff.org/module/how-to-use-signal
• Protest tips: https://ssd.eff.org/module/attending-protest
• Border crossing (varies): https://www.eff.org/issues/border-searches