The Knock System

A Knock is a permission request to begin a conversation.

sequenceDiagram
    participant S as Unknown Sender
    participant N as Null Network
    participant R as Recipient
    S->>N: Submit Knock request
    N->>N: Apply rate limit and policy checks
    N-->>R: Display limited request preview
    R->>N: Accept, reject, or block
    N-->>S: Return decision
    N-->>R: Open conversation if accepted

What a Knock may include

• sender's Null ID;
• short introduction;
• reason for contact;
• selected credential;
• optional anti-spam bond — see Anti-Spam Bonds;
• no file attachment by default;
• no active external link by default.

Recipient actions

• Accept — opens a conversation.
• Reject — closes the request.
• Block — prevents future contact.
• Report — sends the request for abuse review.