Because end-to-end encryption has no good answer to a lost phone, and the answers other messengers chose are worse than they look. All Telegram messages are securely encrypted; the two chat types differ in where the keys live, and that is a deliberate choice rather than a compromise.
The two schemes
| Cloud Chats | Secret Chats | |
|---|---|---|
| Encryption | Client to server and server to client, stored encrypted in the cloud | Client to client |
| New device | Everything is there immediately, even if the old one is gone | Nothing is there |
The problem nobody has solved elegantly
Restoring a chat history onto a newly connected device has no clean solution inside the end-to-end paradigm, because recovery needs a copy and the paradigm forbids one. Reliable backups are nonetheless essential for a mass-market messenger. Three approaches exist:
- Decryptable backups. Applications such as WhatsApp and Viber allow backups that can be decrypted, which puts privacy at risk even for users who never enabled backups themselves, because the other party in the conversation may have.
- No backups at all. Other apps ignore the problem and leave users exposed to losing everything.
- Two distinct chat types. Telegram disables default system backups and provides an integrated, security-focused one in the form of Cloud Chats, while Secret Chats give full control over anything you do not want stored.
The argument people miss
Because Cloud Chats are practical for everyone, Telegram is adopted broadly rather than only by activists and dissidents. That matters directly: in some countries, simply using an end-to-end-only messenger marks a person as worth watching. A service used by everybody provides cover that a specialist tool cannot, and that protection disappears the moment the tool becomes a signal in itself.
Updated