People Nearby is a service offered by Telegram that allows a user to discover other Telegram users, based only on geographical proximity. Nearby users are reported with a rough estimate of their distance from the position of the reference user, allowing Telegram to claim location privacy. In this paper, we systematically analyze the location privacy provided by Telegram to users of the People Nearby service. Although the service protects against precise user localization, we demonstrate that location privacy is always lower than the one declared by Telegram meters.
Specifically, we discover that location privacy is a function of the geographical position of the user. After our responsible disclosure, Telegram updated the FAQ associated with the service.
Finally, we provide some solutions and countermeasures that Telegram can implement to improve location privacy. In general, the reported findings highlight the significant privacy risks associated with using People Nearby service. Instant messaging has become an integral part of modern communication, both for personal and professional use [ 26 ] , [ 10 ]. In this context, Telegram is one of the most popular instant messaging applications.
It was founded in and is based on a centralized Cloud-based architecture, with Cloud servers deployed worldwide and the operational center located in Dubai, UAE [ 14 ].
According to recent statistics, Telegram accounts for million active users monthly and the average Telegram user spends approximately 3 hours per day using the related mobile cellular app [ 6 ]. Security and privacy have been among the selling points of Telegram since its first release [ 9 ].
