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Verify Nostr inbound signatures once, off the main actor

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Every inbound relay event was Schnorr-verified TWICE, both times on the
main actor: once in NostrRelayManager.handleParsedMessage and again in
each NostrInboundPipeline / GeoPresenceTracker handler. Each
verification re-serializes the event JSON, hashes it, and runs a
secp256k1 Schnorr verify, so busy geohashes paid double crypto on the
UI thread. Geohash gift-wrap NIP-17 decryption (two ECDH+ChaCha layers)
also ran on the main actor.

Changes:
- NostrRelayManager now owns a serial off-main inbound pipeline
  (AsyncStream + single consumer task): frames are parsed and verified
  in arrival order off the main actor, preserving per-subscription
  delivery order. This is the single verification point for the whole
  inbound path; downstream handlers only ever see verified events.
- Dedup stays two-phase and unpoisonable: a cheap main-actor duplicate
  LOOKUP runs before verification (duplicate fan-in from several relays
  never pays for crypto — previously every duplicate was verified), and
  events are RECORDED as seen only after the signature verifies, so a
  forged-signature copy can never suppress the genuine event.
- NostrInboundPipeline and GeoPresenceTracker drop their redundant
  re-verification; geohash gift-wrap decryption moves off the main
  actor following the existing account-mailbox Task.detached pattern
  (atomic main-actor check-and-record, then decrypt off-main, then hop
  back for state updates).
- Tests: relay-level coverage for tampered gift wraps and for in-order
  delivery of back-to-back frames; pipeline-level tampered-signature
  tests move to the relay boundary where the invariant now lives; the
  mock relay connection queues frames emitted before receive re-arms.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
jack
2026-07-01 23:40:23 +02:00
co-authored by Claude Fable 5
parent f688e529f6
commit 8af6fc2d5f
8 changed files with 338 additions and 193 deletions
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bitchatTests/GeohashPresenceTests.swift
+5 -20
View File
@@ -326,26 +326,11 @@ struct ChatViewModelPresenceHandlingTests {
#expect(viewModel.geohashParticipantCount(for: activeGeohash) >= 1)
}
@Test func subscribeNostrEvent_samplingInvalidSignatureDoesNotPoisonDedup() async throws {
let (viewModel, _) = makeTestableViewModel()
let sampleGeohash = "u4pru"
let identity = try NostrIdentity.generate()
let event = NostrEvent(
pubkey: identity.publicKeyHex,
createdAt: Date(),
kind: .geohashPresence,
tags: [["g", sampleGeohash]],
content: ""
)
let signed = try event.sign(with: identity.schnorrSigningKey())
var invalid = signed
invalid.sig = String(repeating: "0", count: 128)
viewModel.subscribeNostrEvent(invalid, gh: sampleGeohash)
viewModel.subscribeNostrEvent(signed, gh: sampleGeohash)
#expect(viewModel.geohashParticipantCount(for: sampleGeohash) == 1)
}
// NOTE: Tampered-signature rejection (and the forged-copy dedup-poisoning
// invariant) is enforced once, off the main actor, at the relay boundary —
// the sampling path only ever sees verified events. See
// NostrRelayManagerTests
// `test_receiveEvent_invalidSignatureDoesNotPoisonDuplicateCache`.
// MARK: - Test Helper