A watchtower monitors the blockchain for revoked commitment broadcasts on your behalf and can publish justice transactions if you are offline.
Complete Step 1 // Required reading in the study plan above, then continue here. This closes Implementation.
Step 2 — Core idea: someone watches when you sleep
Phones sleep. Laptops close. Lightning’s penalty model needs someone watching. Towers extend security to intermittent devices.
Analogy: A neighborhood security camera that only unlocks the evidence locker if a specific break-in pattern appears — without learning your daily life (ideally).
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Done when: You can explain why towers do not replace correct backups.
Step 3 — Threat model brief (lab)
Write offline-breach → tower justice, privacy tradeoffs, and one mitigation. Optional LND tower config on Polar.
Done when: Lab evidence (brief + privacy note + source) is complete. Complete the chapter quiz when prompted.
Next lesson
Lightning POS Project — invoices, webhooks, and settlement UX.