Bitchat – A decentralized messaging app that works over Bluetooth mesh networks

Original Article ↗ Hacker News Discussion ↗

Platform & Design

  • Native SwiftUI app targeting iOS/macOS, labeled a “Universal App” in Apple’s sense (iPhone/iPad/Mac).
  • Protocol layer is described as platform‑agnostic; lower‑level Bluetooth handling would need rewriting for Android. A separate Android port already appeared, but not from the original repo.
  • Released under the Unlicense / public domain; some see this as attractive for forking, porting, or embedding in friendlier UIs.
  • IRC‑style commands are a deliberate part of the UX; several people like the “nerdy” feel but note it’s not yet non‑technical‑user‑friendly.

Bluetooth Mesh Feasibility

  • Many praise the idea but question BLE as a basis for a “truly decentralized mesh at scale” due to short range and high packet loss with extended advertising.
  • Others report surprisingly long ranges using BLE coded PHY (~1 km+ line‑of‑sight) and argue it’s sufficient for local/off‑grid use.
  • Debate over reliability: some suggest simple retransmits or flooding; others note flooding doesn’t scale and requires TTLs and careful design.

Use Cases & Limitations

  • Proposed use cases: protests and internet shutdowns, festivals and stadiums with saturated cell towers, airplanes, hiking/cycling, supermarkets or big venues with indoor dead zones, cruise ships, remote communities.
  • Several note that for true resilience in wilderness or over kilometers, LoRa or sub‑GHz radios (e.g., Meshtastic) are more appropriate than BLE.
  • Skeptics argue that if people are within Bluetooth range, talking or standard radios often suffice; mesh only matters once density is high and latency is acceptable.

Security & Protocol Concerns

  • Commenters generally find the design “simple and cool,” but ask about:
    • Timing attacks revealing room membership.
    • How nonces/IVs are managed per room in GCM.
  • Some compare it unfavorably to longer‑standing secure systems (e.g., Briar), especially given the author’s broader privacy reputation.

Relation to Existing Projects

  • Compared and contrasted with: Briar, FireChat, Bridgefy, Meshtastic, Reticulum, Murmur, Meshenger, Berkanan, Scuttlebutt, Delta Chat, and others.
  • Several argue it partly reinvents wheels (BLE mesh standards, Reticulum) but acknowledge its tight Apple integration and E2EE + store‑and‑forward feature set as notable.

Apple Ecosystem, App Store, and Openness

  • Discussion on whether it can ship in the App Store given use of allowed APIs (MultipeerConnectivity/BLE).
  • Broader argument: some want first‑party iMessage‑over‑Bluetooth; others prefer open apps outside Apple’s store but note iOS background limits make serious P2P/mesh hard.
  • Extended debate on Apple’s walled garden, 30% cut, app‑review “security vs freedom,” and comparison with Android’s sideloading.

Economic / Incentive Mesh Ideas

  • A long subthread explores a more general concept: delay‑tolerant, device‑to‑device messaging with micropayments to relay nodes (tokens/Lightning/etc.).
  • Many point out hard problems: needing internet for blockchain, sybil attacks on reward paths, routing in sparse/mobile networks, and the risk of incentives overpowering utility (Helium as example).

Reception

  • Overall tone: technically intrigued, especially by a high‑profile CEO shipping open code, but cautious about practicality, Apple‑only scope, and real‑world adoption.