Introduction into RFB/VNC

Important

Please note, that this section is not completed yet.

Messages

Security Types

The protocol

Handshaking Phase

        sequenceDiagram
    Server->>Client: max. possible ProtocolVersion
    Client-->>Server: answer with selected ProtocolVersion

    Server->>Client: send available SecurityTypes
    Client-->>Server: answer with selected SecurityType

    Note over Server,Client: Communication depending on selected security type

    Server->>Client: send SecurityResult

Protocol for SecurityType 1 (NO-AUTHENTICATION):

        sequenceDiagram
    Server->>Client: max. possible ProtocolVersion
    Client-->>Server: answer with selected ProtocolVersion

    Server->>Client: send available SecurityTypes
    Client-->>Server: answer with selected SecurityType

    Server->>Client: send SecurityResult

Special Case for SecurityType 1 (NO-AUTHENTICATION) and ProtocolVersion 3.3/3.7:

If the server and client decide to use the ProtocolVersion 3.3 or 3.7 and security type 1, the server does not send the SecurityResult message, but will directly continue with the Initialization messages. This is valid for ProtocolVersion 3.3 [4] and 3.7 [5]:

        sequenceDiagram
    Server->>Client: max. possible ProtocolVersion
    Client-->>Server: answer with selected ProtocolVersion

    Server->>Client: send selected SecurityType

    Note over Server,Client: Continue with Initialization messages

Protocol for SecurityType 2 (VNC-AUTHENTICATION):

        sequenceDiagram
    Server->>Client: max. possible ProtocolVersion
    Client-->>Server: answer with selected ProtocolVersion

    Server->>Client: send available SecurityTypes
    Client-->>Server: answer with selected SecurityType

    rect rgb(191, 223, 255)
    Server->>Client: send random 16-byte challenge
    Client-->>Server: DES encrypted challenge (with password)
    end

    Server->>Client: send SecurityResult

Special Case for ProtocolVersion 3.3:

If the server and client decide to use the ProtocolVersion 3.3, the handshaking phase changes. [4] Instead the server is provide a set of possible security types, it will just send a single security type. The security-type may only take the value 0, 1, or 2.

        sequenceDiagram
    Server->>Client: max. possible ProtocolVersion
    Client-->>Server: answer with selected ProtocolVersion

    Server->>Client: send selected SecurityType

    Note over Server,Client: Communication depending on selected security type

Initialization Phase

        sequenceDiagram

    Note over Server,Client: Handshaking Phase

    Client->>Server: ClientInit
    Server-->>Client: ServerInit