Bitchat And Chill 2025 08 14

Date: 2025-08-14
Presenter: Round Rock Bitcoiners

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Outline & Notes

Bitchat and Chill: Offline Bitcoin & Mesh Networking

Source: RRBTC (Round Rock Bitcoiners #38) Date: August 14, 2025

Problem & Solution

• Problem: Bitcoin wallets require network to broadcast transactions. Black-out scenarios make P2P value transfer impossible.
• Solution: Combine offline mesh networking with privacy-preserving eCash (Cashu)

Mesh Network Comparison

| Category | Radio | Examples | Use-Case | | Wi-Fi Mesh | 2.4/5 GHz | 802.11s, Google Nest | Home/City broadband | | Bluetooth Mesh | BLE | Bitchat, Briar | Secure local chat | | LoRa Mesh | Sub-GHz | Meshtastic | Long-range (km), low-bandwidth | | Hybrid | Multiple | Briar, Yggdrasil | Disaster response |

Key Platforms

• Bitchat (Jack Dorsey): Encrypted messenger over BLE. Noise Protocol, multi-hop relays. Payload ~512B.
• Meshtastic: Open-source LoRa firmware. Range 1-5 km. Max payload ~242B.
• Briar: Decentralized Android messenger. Bramble protocol, store-and-forward. Android-only.

Cashu + eCash Workflow

1. Mint: User creates token while online
2. Sender: Copies token (Base64) to clipboard
3. Transfer: Sends via Bitchat/Briar/Meshtastic while offline
4. Receiver: Gets encrypted message via mesh hop
5. Redeem: Redeems with mint once back online

Future Considerations

• Trust in mint required
• Scalability of BLE hops in crowds
• Community-run Cashu mints
• Mesh-first Bitcoin wallets

Slides in this Deck

• Deck Overview (All Slides)
• Slide 1
• Slide 2
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• Slide 9
• Slide 10
• Slide 11
• Slide 12
• Slide 13
• Slide 14
• Slide 15