Cellphone surveillance

Cellphone surveillance (also known as cellphone spying) may involve tracking, bugging, monitoring, eavesdropping, and recording conversations and text messages on mobile phones. It also encompasses the monitoring of people's movements, which can be tracked using mobile phone signals when phones are turned on. StingRay devices are a technology that mimics a cellphone tower, causing nearby cellphones to connect and pass data through them instead of legitimate towers. This process is invisible to the end-user and allows the device operator full access to any communicated data. This technology is a form of man-in-the-middle attack. StingRays are used by law enforcement agencies to track people's movements, and intercept and record conversations, names, phone numbers and text messages from mobile phones. Their use entails the monitoring and collection of data from all mobile phones within a target area. Law enforcement agencies in Northern California that have purchased StingRay devices include the Oakland Police Department, San Francisco Police Department, Sacramento County Sheriff's Department, San Jose Police Department and Fremont Police Department. The Fremont Police Department's use of a StingRay device is in a partnership with the Oakland Police Department and Alameda County District Attorney's Office. End-to-end encryption such as Signal protects traffic against StingRay devices via cryptographic strategies. A tower dump is the sharing of identifying information by a cell tower operator, which can be used to identify where a given individual was at a certain time. As mobile phone users move, their devices will connect to nearby cell towers in order to maintain a strong signal even while the phone is not actively in use. These towers record identifying information about cellphones connected to them which then can be used to track individuals. In most of the United States, police can get many kinds of cellphone data without obtaining a warrant.