WS handshake is now authenticated end-to-end. The broker proves that
every connected peer actually holds the secret key for the pubkey
they claim as identity — not just that they know the pubkey.
wire format change:
{type:"hello", meshId, memberId, pubkey, sessionId, pid, cwd,
timestamp, signature}
where signature = ed25519_sign(canonical, secretKey)
and canonical = `${meshId}|${memberId}|${pubkey}|${timestamp}`
broker verifies on every hello:
1. timestamp within ±60s of broker clock → else close(1008, timestamp_skew)
2. pubkey is 64 hex chars, signature is 128 hex chars → else malformed
3. crypto_sign_verify_detached(signature, canonical, pubkey) → else bad_signature
4. (existing) mesh.member row exists for (meshId, pubkey) → else unauthorized
All rejection paths close the WS with code 1008 + structured error
message + metrics counter increment (connections_rejected_total by
reason).
new modules:
- apps/broker/src/crypto.ts: canonicalHello, verifyHelloSignature,
HELLO_SKEW_MS constant
- apps/cli/src/crypto/hello-sig.ts: matching signHello helper
clients updated:
- apps/cli/src/ws/client.ts: signs hello before send
- apps/broker/scripts/{peer-a,peer-b}.ts (smoke-test): sign hellos
with seed-provided secret keys
new regression tests — tests/hello-signature.test.ts (7):
- valid signature accepted
- bad signature (signed with wrong key) rejected
- timestamp too old rejected (>60s)
- timestamp too far in future rejected (>60s)
- tampered canonical field (different meshId at verify time) rejected
- malformed hex pubkey rejected
- malformed signature length rejected
verified live:
- apps/broker/scripts/smoke-test.sh: full hello+ack+send+push flow
- apps/cli/scripts/roundtrip.ts: signed hello + encrypted message
- 55/55 tests pass
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
