Lightning Network Watchtower

Transcript

1. Lightning Network Watchtower blockchain.tokyo #8 @parakeety

2. ࣗݾ঺հ • Ԭా༸ฏ • github: parakeety • twitter: @parakeety_ •

   ڵຯؔ৺: Lightning Network, DEX, mimblewimble

3. Lightning Network͓͞Β͍ • Bitcoin networkͱ࿈ܞ͢Δ΋͏Ұͭͷp2p network • opening txͱclosing tx͸Bitcoin

   networkʹbroadcast͞ Εॻ͖ࠐ·ΕΔ͕ɺ్தͷcommitment tx͸broadcast ͤͣʹͻͨ͢Βߋ৽͢Δ • commitment tx͸ॺ໊ࡁΈͰ͍ͭͰ΋Bitcoin network ʹ͍ͭͰ΋broadcastͯ֬͠ఆͤ͞Δࣄ͕Ͱ͖Δ

4. 0QFOJOH
   5SBOTBDUJPO $MPTJOH
   5SBOTBDUJPO $PNNJUNFOU
   5SBOTBDUJPO  $PNNJUNFOU
   5SBOTBDUJPO  ΞυϨεA: 5BTC ΞυϨεB: 5BTC

   ΞυϨεA: 4BTC ΞυϨεB: 6BTC ΞυϨεA͔ΒΞυϨεBʹ1BTCૹۚ ΞυϨεAͷॴ༗ऀ͸Commitment Transaction(1)Λbroadcast͢Δincentive͕͋Δ

5. ݹ͍ෆਖ਼ͳCommitment TxΛbroadcastͨ͠৔߹ • ҰఆظؒҎ಺ʹɺऔΓ໭͢tx(justice tx)Λ࡞੒ͯ͠ broadcast͢Ε͹ɺopening txͷdepositΛશͯճऩ͢ Δࣄ͕Ͱ͖Δ

6. ෆਖ਼ͳCommitment txճऩͷ՝୊ • ݹ͍ෆਖ਼ͳcommitment tx͕broadcast͞Ε͔ͯΒɺҰ ఆظؒҎ಺ʹjustice txΛ࡞੒ͯ͠ɺbroadcast͠ͳ͍ͱ ͍͚ͳ͍ • ͭ·ΓɺBitcoin

   networkΛ؂ࢹ͢Δඞཁ͕͋Δ • ৗ࣌ىಈ͍ͯ͠Δfull nodeͰ͋Ε͹Մೳ͕ͩɺϞόΠϧ ୺຤ͩͱݫ͍͠

7. Watchtower

8. Watchtower • ϞόΠϧ୺຤ͳͲͷৗ࣌ىಈ͕೉͍ܰ͠ྔΫϥΠΞϯτ ͷ୅ΘΓʹɺBitcoin NetworkΛ؂ࢹ • ݹ͍Commitment tx͕broadcast͞ΕͨͷΛݕ஌͠ɺ justice txΛbroadcastͯ͘͠ΕΔ

   • LightningͷϑϧϊʔυͷҰػೳͱ࣮ͯ͠૷༧ఆ

9. Watchtowerͷ࢓૊Έ • ܰྔΫϥΠΞϯτ͸ɺCommitment txΛߋ৽͢Δ౓ ʹɺjustice txΛ࡞੒͠ɺWatchtowerʹૹΔ • ͋ͱ͸Watchtower͕ࣗಈͰճऩͯ͘͠ΕΔ • 1ͭͷWatchtowerͰ͸ͳͯ͘ɺෳ਺ͷWatchtowerʹ

   outsource͢Δ

10. WatchtowerͷΠϯηϯςΟϒ • ܰྔΫϥΠΞϯτͷ୅ΘΓʹෆਖ਼ͳCommitment txΛ ৗ࣌؂ࢹͯ͠΋Β͏ࣄʹରͯ͠ରՁΛ෷͏ࣄ͕૝ఆ͞Ε ͯΔ • Retribution: ճऩֹͨۚ͠ͷҰ෦ΛWatchtowerʹࢧ෷ ͏

    • Pay-per-state: Commitment txΛߋ৽͠ɺjustice txΛૹ Δ౓ʹใुΛࢧ෷͏

11. ·ͱΊ • ϞόΠϧ୺຤ͷৗ࣌ىಈ͕೉͍͠ΫϥΠΞϯτͰ΋҆৺ ͯ͠Lightning NetworkΛ࢖͑ΔΑ͏ʹͳΔʹ͸ɺ Watchtower͕ඞཁ