Session-Specific Encryption: Even within an authenticated session, messages (including verification codes or requests related to your number) are further encrypted using a combination of the auth_key and a message_key (derived from the message content and parts of the auth_key). AES-256 in IGE mode is used for symmetric encryption.
Time Synchronization & Replay Protection: MTProto incorporates mechanisms like server_salt and msg_id (message identifiers tied to timestamps) to protect against replay attacks, ensuring that messages related to your phone number verification or account changes are fresh and legitimate.
Secure Remote Password (SRP) for 2FA: When Two-Step Verification (2FA) is enabled, Telegram uses a variant of the SRP-6a protocol. This allows the client and server to verify the 2FA password without ever transmitting the password itself over the network, even in an encrypted form. This is crucial for protecting the password even if the communication channel is compromised.
2. Distributed Cloud Infrastructure
Geographically Distributed Data Centers: User data, including information linked to phone numbers (like account details and cloud chats), is stored in multiple data centers located in different jurisdictions around the world.
Split Encryption Keys (for Cloud Chats): For cloud telegram number database chats (non-Secret Chats), which are stored on Telegram's servers to enable multi-device synchronization, the encryption keys are intentionally stored in several other data centers in different jurisdictions than the actual encrypted data. This means that no single local engineer or physical intruder could gain access to both the encrypted data and its corresponding decryption key.
No Single Point of Failure: This distributed model not only enhances performance but also provides a significant layer of security and resilience against localized attacks or attempts by single governments to demand data.