Manthan Gossip Demo (Phase 3 — The Void Network)

Phase 3 deliverable per the Manthan platform tracker §3 (P-004 + P-005a). Three Manthan nodes communicate over real WebSocket connections using the MWP handshake (G-005) and ENVELOPE_GOSSIP frames (G-006).

What this demonstrates

1. Three independent nodes (Alice, Bob, Carol), each running:
- Its own SQLite ledger (G-010 schema)
- Its own MWP server on an ephemeral port
- Outbound MWP client connections to one peer (forming a ring)
2. Three WebSocket connections / six local MWP session objects (one inbound + one outbound at each node) established via the three-message handshake (HELO → HELO_ACK → HELO_ACK_2) with mutual transcript signatures.
3. Controlled gossip propagation: Alice and Bob originate envelopes; neighbors relay them across the local mesh.
4. Dedupe: when an envelope reaches a node from multiple paths, only the first ingestion is recorded and duplicate frames are counted.
5. Persistence: every received envelope lands in the receiver's SQLite ledger in seen state.

Run

cd demo/manthan-gossip
node --experimental-strip-types src/gossip.ts

Sample output

=== Manthan Gossip Demo (Phase 3 — The Void Network) ===
Alice  sigil:...
Bob    sigil:...
Carol  sigil:...

Ports: Alice=51595 Bob=51596 Carol=51597

[Alice] session established (outgoing→Bob)
[Bob]   session established (incoming)
[Bob]   session established (outgoing→Carol)
[Carol] session established (incoming)
[Carol] session established (outgoing→Alice)
[Alice] session established (incoming)

--- gossip start ---
[Alice] originating envelope id=691bf0b09822… to=Bob
[Bob]   received envelope id=691bf0b09822… from Alice
[Carol] received envelope id=691bf0b09822… from Alice

[Bob]   originating envelope id=f0f8cd394925… to=Carol
[Alice] received envelope id=f0f8cd394925… from Bob
[Carol] received envelope id=f0f8cd394925… from Bob

=== ledger state ===
Alice   seen:1 verified:1  unique-ids-seen=2 duplicate-frames-dropped=...
Bob     seen:1 verified:1  unique-ids-seen=2 duplicate-frames-dropped=...
Carol   seen:2 verified:0  unique-ids-seen=2 duplicate-frames-dropped=...

dedupe verified: dropped ... duplicate frame(s)

shutting down…

The final assertions confirm each node tracked exactly two distinct envelopes, and the duplicate-frame counter confirms dedupe was actually exercised.

What the MWP handshake does

Per G-005, each pair-wise session is established by:

1. HELO — initiator sends version, sigil, fresh nonce, supported envelope/artifact/role types, max frame size.
2. HELO_ACK — responder replies with its own sigil, fresh nonce, the intersection of supported sets, plus transcript_signature (Ed25519 over CBOR-canonical(HELO || HELO_ACK_core)).
3. HELO_ACK_2 — initiator counter-signs the same transcript and emits.
4. Both sides derive session_id = SHA-256(transcript)[0..16].
5. Subsequent frames carry session_id + monotonic seq per direction; non-monotonic seq closes the session immediately.

This defends against:

Replay — fresh nonces produce unique transcripts; replayed HELO_ACK fails on deriveSessionId(transcript) !== ack.session_id.
Downgrade — version is in the signed transcript; tampering breaks the signature.
Splicing — both peers sign the same transcript; HELO from session A + HELO_ACK from session B fails verification on both sides.
Forgery — HELO_ACK signed with the wrong key fails Ed25519 verification (test: mwp server rejects HELO_ACK_2 signed by wrong key).
MITM — when TLS exporter (RFC 5705) is available, both peers include it; mismatch is rejected at HELO_ACK time.

Test coverage

lib/manthan-mwp/test/handshake.test.ts — 10/10 tests covering V1 (healthy), V2 (forged), V3 (replay), V4 (downgrade), V5 (splicing), V6 (TLS exporter mismatch), V7 (unsupported version), V8 (signer identity binding), V9 (TLS exporter stripping), and intersection logic.
lib/manthan-mwp/test/integration.test.ts — 3/3 end-to-end tests on real WebSocket connections.

What this is NOT

Not a production gossip network. No bootstrap discovery, no peer rotation, no anti-eclipse measures (those land in Phase 4 per G-006 §3.1–3.3).
Not encrypted. Frames are JSON over plain WebSocket. Production deployments use wss:// over TLS; the handshake's tls_exporter field binds MWP to the TLS session.
Not authoritative gossip. Receivers ingest envelopes in seen state; full verification + state-machine progression is the receiver's job (Phase 2 ledger handles it).
Not anti-entropy repair. INVENTORY / GET_ENVELOPES frames are typed in frames.ts but not exercised in this demo. Hash-range Merkle reconciliation is a Phase 3.5+ feature.

Cross-references

manthan-platform/gates/G-005-mwp-handshake.md — the spec this implements
manthan-platform/gates/G-006-gossip-discipline.md — gossip frame types
lib/manthan-mwp/ — the MWP library
lib/manthan-ledger/ — the SQLite ledger storing received envelopes
lib/herald-core-ts/src/cbor.ts — CBOR-canonical encoding for transcripts

Manthan Gossip Demo (Phase 3 — The Void Network)