For soldiers on the battlefield, the act of turning on one’s smartphone has been described as the digital equivalent of lighting a cigarette, as doing so creates a signal about one’s location that can be picked up by the enemy. Despite this, smartphones have played a meaningful role in recent conflicts, including Russia’s invasion of Ukraine, where the devices have been used for communicating in the event of radio failure, disseminating on-the-ground footage to counter propaganda and maintaining morale by staying in touch with family and friends. How each side collects the adversary’s smartphone location data and shields their own can mean the difference between victory and defeat.