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* Add capability bits to announce TLV Announces now carry an optional capabilities TLV (0x05): a little-endian bitfield with named bits for upcoming features (prekeys, wifiBulk, gateway, groups, board, vouch, meshDiagnostics). Old clients skip the unknown TLV; peers without it decode as nil so features can distinguish "legacy peer" from "advertises nothing". PeerCapabilities lives in BitFoundation with a minimal-length encoding that preserves unknown bits for forward compatibility. Peer capabilities are stored in the BLE peer registry on verified announce and exposed via BLEService.peerCapabilities(_:). The local advertisement set is empty until each feature ships its bit. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> * Private groups: creator-managed encrypted group chat over the mesh Small encrypted crews (hard cap 16) between public broadcast and 1:1 DMs: Protocol - MessageType.groupMessage = 0x25: broadcast packets with a cleartext 16-byte group ID + epoch, ChaCha20-Poly1305 ciphertext (epoch bound as AEAD AAD), inner Ed25519 sender signature over "bitchat-group-msg-v1"|groupID|messageID|timestamp|content - NoisePayloadType.groupInvite = 0x06 / .groupKeyUpdate = 0x07: creator-signed group state (key, epoch, roster) 1:1 over Noise; signature over "bitchat-group-v1"|groupID|epoch|key-hash|roster-hash and the Noise session peer must BE the creator - SyncTypeFlags bit 10 (groupMessage): variable-length LE bitfield widens 1 -> 2 bytes inside the length-prefixed REQUEST_SYNC TLV; old clients ignore unknown bits and answer with types they know - PeerCapabilities.localSupported now advertises .groups Storage - GroupStore: symmetric keys in the keychain, roster/name/epoch as protected JSON in Application Support; wiped in panicClearAllData() Behavior - Non-members relay 0x25 like any broadcast but cannot read it; group messages join gossip-sync backfill with the public-message window - Receivers drop wrong-epoch envelopes, bad sender signatures, and senders missing from the creator-signed roster - Fire-and-flood delivery (no per-member acks in v1) UI - Groups open as chat windows through the private-chat sheet (virtual "group_" peer IDs); groups section in the people sheet; /group create/invite/remove/leave/list commands; invitees get a system message + notification and the group appears in their people sheet Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> * Private groups: fix TLV truncation, roster downgrade, removal notice, block, media, signable bytes Addresses the Codex review and adversarial-review findings on #1383: - TLV encoding now throws GroupTLVError.valueTooLong instead of clamping to 65535 and truncating, so an oversize group message fails to seal and surfaces send_failed rather than shipping ciphertext recipients drop. - Roster nicknames truncate on a Character boundary (never mid-scalar), so a multi-byte nickname can no longer make the whole signed roster undecodable. - Invites now bump the epoch (rotate the key) like removals, giving every roster change a strictly-increasing epoch so out-of-order invite states no longer last-writer-wins a just-added member back out. - Removing a member now sends them a creator-signed roster-without-them under a throwaway all-zero key (never the rotated key), so their client deactivates the group and surfaces "removed" instead of going silently dark. - /block is enforced in the group receive path: a blocked member's messages are dropped from display and notifications, consistent with every other inbound path. - Media affordances are disabled in group chats (both computed sites) so the composer can't strand a media placeholder that never sends; media-in-groups is a documented v2 item. - Creator signature now covers the group name and the sender signature covers the epoch (wire-format-affecting; needs Android parity before ship). - Explicit isGroup guard in markPrivateMessagesAsRead so read/delivered receipts can never leak into group conversations under a future refactor. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> --------- Co-authored-by: jack <jackjackbits@users.noreply.github.com> Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Test Harness Guide
This test suite uses an in-memory networking harness to make end-to-end and integration tests deterministic, fast, and race-free without touching production code.
In-Memory Bus
- File:
bitchatTests/Mocks/MockBLEService.swift - Registry/Adjacency: Global
registrymapspeerIDto aMockBLEServiceinstance;adjacencyrecords simulated links between peers. - Setup: Call
MockBLEService.resetTestBus()insetUp()to clear state between tests. - Topology: Use
simulateConnectedPeer(_:)andsimulateDisconnectedPeer(_:)to add/remove links.connectFullMesh()helpers in tests build larger topologies. - Handlers: Tests can observe data via
messageDeliveryHandler(decodedBitchatMessage) andpacketDeliveryHandler(rawBitchatPacket). - De‑duplication: A thread-safe
seenMessageIDsprevents duplicate deliveries during flooding/relays.
Broadcast Flooding
- Flag:
MockBLEService.autoFloodEnabled - Intent: When
true, public broadcasts propagate across the entire connected component (ignores TTL for reach) while still de‑duping to prevent loops. - Usage: Enabled in Integration tests (
setUp) to simulate large-network broadcast; disabled in E2E tests to keep routing explicit and verify TTL behavior (seePublicChatE2ETests.testZeroTTLNotRelayed).
Rehandshake Flow (Noise)
- Why: The legacy NACK recovery path was removed; recovery now relies on Noise session rehandshake after decrypt failure or desync.
- Manager:
NoiseSessionManagermanages per-peer sessions. - Pattern: On decrypt failure, proactively clear the local session and re-initiate a handshake. The peer accepts and replaces their session.
- Test:
IntegrationTests.testRehandshakeAfterDecryptionFailure- Corrupts ciphertext to induce a decrypt error.
- Calls
removeSession(for:)on the initiator’s manager beforeinitiateHandshake(with:)to avoidalreadyEstablished. - Verifies encrypt/decrypt succeeds post-rehandshake.
Tips
- Determinism: Add small async delays only where handler installation/topology changes could race the first send.
- Scoping: Keep
autoFloodEnabledtoggled only within Integration tests; always reset intearDown()to avoid cross-test contamination. - Direct vs Relay: Private messages target a specific peer when adjacent; otherwise they are surfaced to neighbors for relay and, if known, also delivered to the target.
Quick Start
- Create nodes and connect them:
let svc = MockBLEService(); svc.myPeerID = "PEER1"svc.simulateConnectedPeer("PEER2")
- Observe messages:
svc.messageDeliveryHandler = { msg in /* asserts */ }
- Enable broadcast flooding for Integration suites only:
MockBLEService.autoFloodEnabled = true