pds-message-poc#

interactive browser demo of PDS-to-PDS message passing.

demonstrates jacob.gold's proposal: PDSes have incoming message queues for DMs, like email servers.

run#

git submodule update --init
bun install
bun dev

usage#

• type a message, select sender → recipient
• send - initiates message (first message creates a request)
• accept - recipient accepts pending request, messages flow freely
• reject - recipient rejects request and blocks sender
• spam - labeler marks sender as spam (rejected by all PDSes)

what's happening#

┌─────────────────┐                              ┌─────────────────┐
│   Bob's PDS     │                              │   Alice's PDS   │
├─────────────────┤                              ├─────────────────┤
│                 │  1. getServiceAuth(aud=alice)│                 │
│  send_message() │ ────────────────────────────>│                 │
│                 │  2. JWT: iss=bob aud=alice   │  inbox queue    │
│                 │ <────────────────────────────│                 │
│                 │                              │                 │
│                 │  3. POST /inbox + JWT        │                 │
│                 │ ────────────────────────────>│  evaluate():    │
│                 │                              │  - token valid? │
│                 │                              │  - spam label?  │
│                 │                              │  - blocked?     │
│                 │                              │  - accepted?    │
│                 │                              │  - rate limit?  │
│                 │  4. {status: ...}            │                 │
│                 │ <────────────────────────────│  → deliver/queue│
└─────────────────┘                              └─────────────────┘
                           │
                           ▼
                   ┌───────────────┐
                   │   Labeler     │
                   │  (reputation) │
                   │  spam labels  │
                   └───────────────┘

invitation flow#

first contact requires acceptance (like DM requests):

1. bob sends message to alice → creates request (message held)
2. alice sees request in her "requests" section
3. alice clicks accept → original message delivered, bob now accepted
4. subsequent messages from bob deliver immediately (subject to rate limits)

alternatively:

• alice clicks reject → request deleted, bob blocked permanently

what's demonstrated#

what's real#

uses pds.js crypto primitives via git submodule:

• P-256 key pairs - each simulated PDS generates real keys on startup
• ES256 JWT signatures - service auth tokens are cryptographically signed
• signature verification - recipient verifies JWT against sender's public key via WebCrypto
• proper JWT structure - iss, aud, lxm, exp, iat, jti fields

what's mocked#

prior art#

• AT Protocol and SMTP - ngerakines on PDS as crypto service, SMTP as transport
• bourbon protocol - invitation-based messaging, combating spam

references#

• jacob.gold's thread
• pds.js - cloudflare workers PDS (crypto primitives used here)
• official PDS
• service auth
• AT Protocol specs