Telegram launched on iOS on August 14, 2013, with an Android alpha following on October 20, 2013. It describes itself as one of the top five most downloaded apps in the world, with over 1 billion active users.
Encryption: what is and is not end-to-end
Telegram is frequently described as an encrypted messaging app, which is accurate only with an important qualification the company itself states. Ordinary Telegram chats — “cloud chats” — use server-client encryption, meaning Telegram’s servers can access message contents. Only Secret Chats, which a user must start deliberately, add client-client (end-to-end) encryption. Group chats and broadcast channels are cloud chats and are not end-to-end encrypted.
Channels and moderation
Alongside private messaging, Telegram carries broadcast channels and large group chats, which is what makes it function as a distribution medium rather than only a messenger. Telegram states that it processes takedown requests for illegal public content — sticker sets, bots, groups and channels — but that this does “not apply to local restrictions on freedom of speech,” and that it will not act on politically motivated censorship requests while it does block terrorist-related content.
Sources
- 01.
Telegram. Telegram FAQ. Source for the launch dates — Telegram for iOS on August 14, 2013 and the Android alpha on October 20, 2013 — the claim of "over 1 billion" active users, the two-tier encryption model (server-client encryption for cloud chats, additional client-client encryption only in Secret Chats), and the moderation policy: takedown requests are processed for illegal public content such as sticker sets, bots, groups and channels, but this does "not apply to local restrictions on freedom of speech."