Is Telegram really an encrypted messaging app?

Telegram ’s CEO Pavel Durov has been arrested by French authorities for his failure to sufficiently moderate content.

Many news reports about the arrest refer to Telegram as an “encrypted messaging app” This phrasing drives me nuts because in a very limited technical sense it's not wrong.

But in every sense that matters, it fundamentally misrepresents what Telegram is and how it works in practice.

Telegram ’s encryption has been subject to heavy criticism since at least 2016 (and possibly earlier) for many of the reasons I outlined in this post.

Many people who join for its social media features also end up using it to communicate privately.

Telegram knows its encryption is difficult to turn on, and they continue to promote their product as a secure messenger.

The owners of Telegram have more or less kept their encryption UX unchanged since 2016 .

Telegram ’s Secret Chats feature is based on a custom protocol called MTProto 2.0 .

This system uses 2048 -bit

finite-field Diffie-Hellman key agreement, with group parameters chosen by the server.

The resulting keys are then used to power the most amazing, non-standard authenticated encryption mode ever invented, something called “ Infinite Garble Extension ” ( IGE ).