Cloud vs secret chats

Cloud chats: encrypted client-to-server, decrypted + stored at server. Accessible from any device. Default.

Secret chats: E2E via MTProto with PFS. Single-device. Optional.

Advertisement

Cloud vs secret chats

Cloud chats: encrypted client-to-server, decrypted + stored at server. Accessible from any device. Default.

Secret chats: E2E via MTProto with PFS. Single-device. Optional.

Advertisement

MTProto transport

Custom protocol atop TCP/UDP. Binary encoding. Focused on mobile efficiency + reconnection.

Distributed data centers

Multiple DCs globally. User assigned to nearest. Data replicates across DCs for redundancy.

Bots + huge groups

Cloud model enables server-side bots + groups of 200K members. E2E would prohibit both at scale.

Criticism of MTProto

Custom crypto (vs Signal Protocol) has raised concerns. Cloud storage is a legal/political risk in some jurisdictions.