Offlink

Offline-first, privacy-first peer-to-peer messaging over Bluetooth Low Energy (BLE).

Offlink is designed to exchange messages without relying on the internet, a SIM card, a mobile network, or a central messaging server.

Current status

Phase 0 — Architecture + verification foundation

The repository intentionally starts with documentation and CI rules before implementing BLE messaging.

Product principles

• Offline by default for core messaging.
• BLE-based application-level store-and-forward mesh.
• End-to-end encrypted message content.
• Relay nodes forward ciphertext; they do not need plaintext.
• Optional one-time location sharing.
• Low battery consumption is a first-class requirement.
• Minimal collection and local-first storage of personal data.
• Android-first MVP; iOS and ESP32 follow after the protocol is stable.
• Simple architecture with clear interfaces and Open/Closed Principle.
• Every phase has a verification gate.

Planned topology

Phone A <-> Phone B <-> Phone C
                    ^
                    |
                  ESP32

A message can travel through multiple nodes while its content remains encrypted.

Repository rules

• Do not push directly to main.
• Work on a feature branch.
• Open a Pull Request.
• Required GitHub Actions checks must pass.
• Human review is required before merging protocol/security changes.
• Never commit secrets, private keys, real user data, or credentials.

Documentation map

• BRAIN.md — AI/project context and non-negotiable rules.
• ARCHITECTURE.md — system structure and boundaries.
• PROTOCOL.md — packet and transport protocol.
• SECURITY.md — security model and controls.
• THREAT_MODEL.md — threats and mitigations.
• BLE.md — BLE/GATT design.
• BATTERY.md — power strategy and measurement.
• DATABASE.md — local data model.
• PRIVACY.md — privacy engineering baseline.
• DATA_MAP.md — what data exists, where it lives, and why.
• RETENTION.md — retention/deletion rules.
• VERIFICATION.md — phase acceptance criteria.
• TEST_MATRIX.md — test scenarios.
• ROADMAP.md — implementation phases.
• DEVELOPMENT.md — local development.
• CONTRIBUTING.md — contribution and PR rules.
• docs/DECISIONS.md — architecture decisions.
• docs/SOURCES.md — verified external sources.

License

License decision is intentionally pending until the project owner chooses the desired open-source terms.