miniproto.crypto.mtproto.message_key

miniproto.crypto.mtproto.message_key

message_key(auth_key: bytes, plaintext_with_padding: BytesLike, *, client_to_server: bool = True) -> bytes

Derive the 16-byte MTProto 2.0 message key.

Parameters:

• auth_key (bytes) – Exactly 256 bytes of authorization-key material.
• plaintext_with_padding (BytesLike) – Complete plaintext including valid MTProto padding.
• client_to_server (bool) – Uses the client-to-server offset when true (the default); false selects the server-to-client offset.

Returns:

• bytes – The direction-bound message key used for AES key and IV derivation.

Raises:

• ValueError – If auth_key has an invalid length.

This deterministic derivation does not validate the supplied padding; use :func:encrypt_payload to create a complete encrypted payload.