Pubkey.Chat

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Pubkey.Chat is an example of the WMAP protocol in action. It is an IRC-like experience where all outgoing messages are signed with your SSH key, and all incoming messages are verified against the author's pubkeys. Every GitHub user's ssh pubkeys are publicly available.

Architecture

Sending and Receiving Messages

Every message is signed with your SSH private key, and then posted in a public place. Your friends can verify these messages came from you by checking the signature against your SSH public keys on GitHub. See WMAP for more information on signing and verification.

sequenceDiagram
    participant GitHub
    participant Pubkey.Chat
    participant Alice
    participant Bob
    Alice->>GitHub: Upload SSH Pubkey
    note over Alice: sign message with <br/> SSH Private Key
    Alice->>Pubkey.Chat: POST to TOPIC
    loop Polling
    Bob->>+Pubkey.Chat: GET latest message for TOPIC
    end
    Pubkey.Chat->>-Bob: New Message from Alice
    Bob->>GitHub: GET Alice's SSH Pubkey
    note over Bob: Verify message against <br/> Alice's SSH Pubkey

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For the sake of keeping the code simple and easy to auditable, the client polls for new messages using repeated HTTP GET queries.