Scaling Problem and Sidechain

A Lecture at Tokyo University

Transcript

1. εέʔϦϯά໰୊ͱ αΠυνΣʔϯٕज़ Cryptoeconomics Lab CTO - Sg
2. ϒϩοΫνΣʔϯ͸෺ཧֶͰ͢
3. Crypto - ҉߸ͷ
 Economics - ܦࡁֶ ͲΜͳܥ΋φογϡۉߧͱͯ͠ϞσϧԽ →ۉߧΛҠಈͤ͞ΔվળΛఏҊ →߈ܸΛίϛϡχςΟͱߟ͑Δ →؇࿨ΛίϛϡχςΟͱߟ͑Δ
4. πϘ bottleneck critical path Ҡಈͤ͞Δ΂͖φογϡۉߧ͸ͲΕ͔
5. ͏·͘վળ͢Δͱ࣍ͷπϘ͸มΘΔ
6. πϘ෼ੳ → ൃ໌ ↑ ↓ ؇࿨ ← ߈ܸߟҊ
7. Ϋϥ΢υΞʔΩςΫτ ήʔϜཧ࿦(ϛΫϩܦࡁ) ηΩϡϦςΟ޻ֶ
8. C2CΞϓϦاۀͷCTO ηΩϡϦςΟΩϟϯϓ ඈߦػ։ൃऀ
9. ϒϩοΫνΣʔϯͷຊ࣭ͱ͸ Permissionless Atomic State Machine
 Replication ୭Ͱ΋ࢀՃͷ த్൒୺͡Όͳ͍ ΦϯϥΠϯήʔϜ౳ͷ ਐΈ۩߹ͷ
 ਖ਼͍͠όοΫΞοϓͷ؅ཧํ๏
10. ڐՄͳ͘୭Ͱ΋ࢀՃͰ͖Δ Ͱ΋յ͞Εͳ͍ ڐՄΛग़͢Ϧʔμʔ͕͍ͳ͍ ௵ͨͯ͘͠΋௵͢૬ख͕͍ͳ͍ Permissionless
11. ϓϥΠϕʔτνΣʔϯͷ͜ͱ ࢀՃ͕ڐՄ੍ ߴ଎ͰɺDBͱ΄΅Ұॹ ίϯιʔγΞϜ͸࡞Γ΍͍͢ σʔλվ᜵͸ͦͦ͜͜͞Εʹ͍͘ ༨ஊ: Permissioned
12. ϓϥΠϕʔτνΣʔϯͷ͜ͱ ࢀՃ͕ڐՄ੍ ߴ଎ͰɺDBͱ΄΅Ұॹ ίϯιʔγΞϜ͸࡞Γ΍͍͢ σʔλվ᜵͸ͦͦ͜͜͞Εʹ͍͘ ༨ஊ: Permissioned
13. फڭ্ͷཧ༝Ͱ ϓϥΠϕʔτνΣʔϯͷ ࿩͸͠·ͤΜ
14. Permissionless Atomic State Machine
 Replication TxΛ1ສϊʔυʹίϐʔ͍ͨ͠ ෆಛఆଟ਺ʹίϐʔ͢Ε͹௵͞Εͳ͍
 ܖ໿ͱ͍͏ͷ͸Ձ஋ʹର͢Δঢ়ଶભҠͷهड़
15. Bitcoin(Ձ஋͕ୈ1ڃࢢຽ) Ethereum(σʔλ͕ୈ1ڃࢢຽ) શ෦σʔλɻ Ձ஋΋ɺՁ஋ͷରՁʹͳΔσʔλ΋ɺͳΜ Ͱ΋ͳ͍σʔλ΋ɺͲ͏ಈ͔͔͢શ෦νΣʔ ϯʹΞοϓϩʔυ͓ͯ͘͠ελΠϧ Ձ஋ϕʔεɻ ͋ΔՁ஋ΛͲ͏ॲཧ͢Δ͔ɻ ෳࡶͳ͜ͱ͸Ͱ͖ͳ͍ɻ
16. PermissionlessͳϒϩοΫνΣʔϯͷಛ௃: - ୈࡾ࣍ੈքେઓͰ΋௵͞Εͳ͍҆৺ײ͋ΔγεςϜ - Φʔϓϯιʔεʹͯ͠ॳΊͯ҆શূ໌Ͱ͖Δ࢓૊Έ - ΦʔϓϯιʔεʹͲΜͲΜ੒Ռ͕ग़Δ - Φʔϓϯͳܝࣔ൘Ͱϥϑʹٞ࿦΍ݚڀΛ͢Δ - ҆ఆੑ΍ੑೳʹؔ͢Δ෦෼͸ϓϩτίϧ೚ͤΒΕΔ - ϓϩτίϧ(ن֨)ଆʹΠϯηϯςΟϒઃܭ͕͋Δ - Ұ౓ެ։͢ΔͱΑͬΆͲ͡Όͳ͍ݶΓߋ৽Ͱ͖ͳ͍ - ֎ͷੈքͷσʔλΛऔΓࠐΉͷʹҰۤ࿑͢Δ - τϥϯβΫγϣϯ(Tx)͕֬ఆ͢Δͷ͕ΊͬͪΌ஗͍ - Txͷಉ࣌ॲཧ਺͕ΊͬͪΌগͳ͍ - DoS(ݏ͕Βͤ)ରࡦʹͲΜͳTxʹ΋ख਺ྉ͕͋Δ
19. WebͷϊϦͰࢀೖ͖ͯͯ͠ ʮͳʹ͜ΕΫι͡ΌΜʯ ͱు͖ࣺͯͯఫୀ͢Δࣄྫଟ਺ ࠓ೥΋ͨͿΜͦ͏͍͏ͷ͕૿͑Δ
20. ͳͥ஗͍ʁ ΰγοϓΞϧΰϦζϜͱ͍͏ ϒϩοΫ/Tx఻೻ํࣜͰ1ສϊʔυ͸ ͪΐͬͱ͕͔͔࣌ؒΔɻ
21. pBFTʹͯ͠ϊʔυݮΒ͢Ҋ 33%߈ܸ଱ੑʹམͪΔ CSతͳηΩϡϦςΟϞσϧ Ͱ͸ͳ͘੓࣏తͳ΍ͭʹͳΔ ʢ࿫࿎߈ܸʣ ָ؍తཁ݅ʹ͔͠࢖͑ͳ͍
22. ઐ໳༻ޠղઆ1 TxͷΩϟύͰ͋ͬͯԠ౴଎౓Ͱ͸ͳ͍
23. Finality & Confirmation ઐ໳༻ޠղઆ2 TxͷԠ౴଎౓͕ͩɺऔҾֹۚʹΑͬͯ߈ܸ֬ ཰͸ҧ͏ͷͰ΢ΥϨοτʹΑͬͯ௕͔ͬͨΓ
24. ηΩϡϦςΟ ઐ໳༻ޠղઆ3 ϓϩάϥϜͷόά͚ͩͰ͸ͳ͘ γεςϜΛμϝʹ͢Δ߈ܸظ଴஋ͱె࿑ײͷ ܦࡁֶతͳόϥϯε΋ηΩϡϦςΟͷൣᙝ
25. σʔλΛॻ͖׵͑Δൣғ͕ඃΒͳ ͍΍ͭΛฒྻԽ͠Α͏Ҋ ൣғ͕͔ͿΒͳ͍ͱ ΊͬͪΌૣ͍͕ɺ͔ ͿΔͱ஗͍. ·͋༗ྗ ͳεέʔϦϯάͷ͏ ͪͷͻͱͭ. Sharding!
26. ॲཧΛ֎஫͠Α͏Ҋ ຊ౰ʹ͍ΖΜͳఏҊ͕͋Δ
27. ຊ࣭ʹཱͪฦΔͱ "Ethereum" Λεέʔϧ͍ͤͨ͞ ETHΑΓ҆͘߈ܸͰ͖ΔͳΒ ͦΕ͸ETH͡Όͳ͍
28. ETHʹஔ͍͍ͯΔ͓ۚΛ μϝͳαΠυνΣʔϯʹ ETHΑΓ҆͘߈ܸͰ͖ΔͷͰ ϦεΫ૿
29. μϝͳαΠυνΣʔϯΑΓ EOSͷ͕Ϛγ
30. μϝͳαΠυνΣʔϯ ͬͯ ಠࣗνΣʔϯ͡ΌͶʁ
31. αΠυνΣʔϯ͸ݬ૝
32. ͦ΋ͦ΋αΠυνΣʔϯ ͱ͍͏ݴ༿Λ ୭͕ݴ͍ग़ͨ͠ͷ͔Ṗ
33. ྑ࣭ͳαΠυνΣʔϯͱ͸Կ͔
34. ྑ࣭ͳαΠυνΣʔϯͱ͸ ਌νΣʔϯͷηΩϡϦςΟΛ࣋ͭ
35. Plasma Off-chain Transaction Verification Protocol
36. Ethereumͷࢿ࢈อશੑͷ·· ॲཧΛ҆શʹΦϑϩʔυ͢Δٕज़ ΤάθΫςΟϒαϚϦ
37. ΤάθΫςΟϒαϚϦ2 ళฮͰTx͕2ඵͰ֬ఆͰ͖Δ ҰํͰݸਓؒૹۚͷfinalityΛՄมʹ ΤϯυϢʔβʔ͸Ψεෆཁ ΤεΫϩʔίϯτϥΫτ౳Մ ·ͣ͸ҡ࣋අ͸~1000ສԁ/೥
 ҡ࣋අ͸νϡʔχϯάͰ҆͘ͳΔ໨ॲ͋Γ
38. ࢓૊Έʹ͍ͭͯ
39. H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H H Sparse Merkle Tree (ૄϚʔΫϧ໦) Bob΁
 1000JPY ૹΓ·͢
 Alice ϒϩοΫ
40. Bob΁
 1000JPY ૹΓ·͢
 Alice Merkle Root͸ETHʹอଘ ࢠνΣʔϯͷຖϒϩοΫੜ੒࣌ Proof͸΢ΥϨοτʹอଘ TxBytes΋΢ΥϨοτʹอଘ
41. Bob΁
 1000GYENૹΓ·͢
 Alice Merkle Root͸32bytes TransactionѹॖޮՌ ߴ͞5ͷπϦʔ͸Proof͕5ͭ 1Tx 100bytes~͘Β͍ͷαΠζ
42. ࣌ؒ blocktime 1෼ શͯͷϒϩοΫͷProofΛ͓࣋ͬͯ͘͜ͱͰɺ ࢠνΣʔϯTransactionͷଘࡏূ໌͕Ͱ͖Δ
43. TransactionͷѼઌ͕ͻͱͭ औҾཤྺ͕Ұ௚ઢ JPY
44. ͋Δ༬ۚΠϕϯτ͔ΒḷͬͯɺऔҾཤྺ͕Ұ௚ઢ Alice Bob Carl David
45. Davidͷ͓ۚΛӡӦ͚ͩվ͟ΜͰ͖Δ͕ ѱ͍͜ͱΛ͠Α͏ͱͯ͠΋ɾɾɾ Alice Bob Operator David ଞਓͷ͓ۚͰ Exit 1week଴ͪ
46. Operator͸ɺDavidʹ͓͕ۚ౉ΔTxͷ ଘࡏূ໌ʹ߹ҙ͍ͯ͠ΔͷͰ Alice Bob Operator David Exit Carl David Challenge
 (ҟٞਃཱͯ)
47. ΋͠ଘࡏূ໌ʹΦϖϨʔλʔ͕߹ҙ͍ͯ͠ͳ͔ͬͨΒʁ Alice Bob Carl David Carl: “ૹ͕ۚಧ͔ͳ͍ʂ”
 Carl:
 “ࢿ࢈ΛकΔͨΊʹExit͢Δʂ” Operator:
 “CarlͷUTXOΛ࢖༻͢ΔUTXO΋ͳ͍͠ɺཤྺ΋ਖ਼ ͍͔͠ΒɺWithdrawͯ͠΋͍͍Α” Txੜ੒ Txੜ੒ Txੜ੒ Commit Commit Conf Conf Exit Conf Conf Conf Conf David:
 “Carl͸ૹ͍ۚͨͬͯ͠͏͚ ͲɺConfͱΕͳ͍͔Β঎඼ ͸౉ͤͳ͍ͳ͋”
48. Only one honest user ݪଇ ࣗ෼Ҏ֎͸ΈΜͳάϧ
49. ཤྺʹΑΔෆਖ਼ূ໌
 (શෆਖ਼औҾ͸ҟٞਃཱͯՄ) ଘࡏূ໌ (Merkle Proof) Proof of Silence
 (ʮ௜໧͸ੋͳΓʯݪଇ) Ethereumͱಉ͡ηΩϡϦςΟΛ΋ͨΒ͢ ઈົͳτϨʔυΦϯؔ܎ Trustless Sidechain
50. Proof of Silence a.k.a Optimist Pattern
 (ʮ௜໧͸ੋͳΓʯݪଇ) ݟ׳Εͳ͍୯ޠ͕ɾɾɾ Exit͕Withdraw͞ΕΔʹ͸ʮ΋͠ෆਖ਼ʹExit͞ΕΑ͏ͱ͠ ͍ͯΔ࢒ߴͷ࣋ͪओ͕͍ΔͳΒɺͦΕʹؾ͚ͮΔ͚ͩͷ े෼ͳ࣌ؒΛ଴ͭʯͱ͍͏৚͕݅͋Δɻ͜Ε͸҉໧ʹ ʮͦͷࣄલऔΓܾΊͷ্Ͱෆຬ͕ͳ͍ͳΒɺͦͷ Withdrawal͸ਖ਼౰ͳͷͩΖ͏ʯͱ͍͏ϧʔϧ͕͋Δɻ͜ ΕΛ “Proof of Silence” ͱ໋໊͓ͯ͘͠ͱɺཧղ͠΍͢ ͍ɻ͋͘·Ͱɺ୭͔͕໌ࣔతʹঝೝ͠ͳ͍ઃܭͰҾ͖ग़ ͠Λݕূ͍͔ͨ͠Β͜ͷΑ͏ͳઃܭʹͳ͍ͬͯΔɻ
51. ࢿ࢈อશੑ100% ҆ఆՄಈੑ99.999999% ਺ֶతอূ ޻ֶతվળ ཉுΒͳ͍͠ద౰ʹࡁ·ͤͳ͍όϥϯε
52. ࢿ࢈อશੑ100% ҆ఆՄಈੑ99.999999% ਺ֶతอূ 0.000001%͕ى͖ͨ ͜Μͳͱ͖Ͳ͏͢Δʁ
53. ނো͔ѱҙ͔αʔόʔఀࢭ
 Ͱ΋τϥετϨεͳͷͰ PlasmaࢠνΣʔϯ αʔόʔ Plasma਌νΣʔϯ
 ίϯτϥΫτ 0.000001% 1. ͓͕ۚಈ͔ͤͳ͍… 2. ୤ग़
54. Ongoing Research 0.5ඵTx: Fast Finality τʔΫϯͷަ׵: Swap Tx ҡ࣋අͷઅ໿: Commit Aggregation Stable Coinͷಋೖ
55. ೔ຊͰͷԠ༻ AlipayͱมΘΒͳ͍଎౓Ͱ࢖͑Δ ۜߦɾେاۀɾελʔτΞοϓͷ ൃߦ͢ΔԁݐͯεςʔϒϧίΠϯΛ Plasma಺Ͱ૬ޓӡ༻ ΤεΫϩʔΛ࢖ͬͨΞϓϦ͕Ұؾʹ૿͑Δ
56. ৽ڵࠃͰͷԠ༻ γΣΞϦϯάΤίϊϛʔܥΞϓϦ͕ ҆৺ͯ͠࢖͑ΔΑ͏ʹͳΔ ܾࡁػೳΛͦΕͧΕ͍࣋ͬͯΔ͕ɺ ݱ஍௨՟ݐͯτʔΫϯͳͷͰ૬ޓӡ༻ָ͕ ΠϯυωγΞͷGoJEKͷΑ͏ʹ ΠϯϑϥʹͳΔ ੓෎͕৴༻Ͱ͖ͳ͍ࠃ͸ WBTC΍BTCTϕʔεͰऔҾ͢Δ
57. ΑΓҡ࣋අ͕҆͘ͳΓ ୭Ͱ΋࢖͑Δಓ۩ʹͳΔ After Serenity
58. τϥϯβΫγϣϯͷ ϓϩάϥϚϒϧԽ τϥϯβΫγϣϯͷ θϩίετԽ ॏཁͳύϥμΠϜ
59. Nash EquillibriumΛNudge͢Δ޻ֶ Security GuaranteeͰޡຐԽ͞ΕΔͳ ·ͱΊ ωοτϫʔΫޮՌͱθϩԽ͢Δม਺ΛݟΑ