Telegram took the world by storm when it was first released in 2013. The brainchild of the Durov brothers, the founders of VKontakte (known as “Russia’s Facebook”), the cloud-based app soon became a synonym for secure, end-to-end encrypted messages, and a wide range of channels and user-friendly features. Telegram was an immediate hit and grew exponentially. From only 100,000 active daily users in October 2013, it reached 100 million in January 2016 and 500 million by the end of 2020: As of today, Telegram is the fifth most popular messaging app in the world: Despite its success and growth, recent events have begun to put into doubt the reputation of Telegram as the go-to safe messaging app: In June 2019, hackers were able to break into the Telegram accounts of thousands of top Brazilian officials, including President Bolsonaro In March 2020, Telegram mistakenly exposed the data of 42 million users (user account IDs, phone numbers, and names). Telegram suffered a massive data leak in August 2020 that exposed the personal data of over 500 million users. Cybercriminals were able to take advantage of Telegram’s chat scripting tools to hack bank account data. The cyber unit of the Chinese government claimed in 2018 to be able to hack into Telegram. These events have led millions of users to openly ask: is Telegram really that safe? Telegram’s Weaknesses, Exposed Telegram has been designed in a way that by default exposes its users...