![Distributed Hash Tables
• Open Services [OpenDHT]
• File sharing [CFS, OceanStore, PAST]
• Web cache [Squirrel, Coral]
• Censor-resistant stores [Eternity, FreeNet]
• Application-layer multicast [Narada, Scribe]
• Event notification [Scribe]
• Streaming [SplitStream]
• Naming systems [ChordDNS, INS]
• Query and indexing [Kademlia]
• Communication primitives [I3]
• Backup store [HiveNet]
• Web archive [Herodotus]](https://image.slidesharecdn.com/icdcsblockchainspedro-190612162705/85/Please-do-not-decentralize-the-Internet-with-permissionless-blockchains-8-320.jpg)
Please, do not decentralize the Internet (with permissionless) blockchains
- 1. Please, do not decentralize the Internet with (permissionless) blockchains Pedro García López, Alberto Montresor, Anwitaman Datta
- 2. Table of Contents • Motivation • History of P2P Networks • Blockchain hype and problems • Edge-centric computing and permissioned blockchains • Conclusions 2
- 3. MOTIVATION
- 4. Edge-centric Computing: Vision and Challenges 4 IEE P2P Steering Committee “In many aspects of human activity, there has been a continuous struggle between the forces of centralization and decentralization. Computing exhibits the same phenomenon; we have gone from mainframes to PCs and local networks in the past, and over the last decade we have seen a centralization and consolidation of services and applications in data centers and clouds.”
- 7. Distributed Hash Tables N1 N8 N14 N32 N21 N38 N42 N48 N51 N56 m=6m=6 K54 2m -1 0 N8+1 N8+2 N8+4 N8+8 N8+16 N8+32 N14 N14 N14 N21 N32 N42 Finger table +32 +16 +8 +4 +2 +1 lookup(K54) key pos 00 hash functionhash function 11 22 N-1N-1 33 ... xx yy zz lookuplookup (key) → data insert (key, data) lookuplookup (key) → data insert (key, data) ““Beattles”Beattles” 22 hash table hash bucket h(key)%Nh(key)%N 0 1 2 ... node key poshash functionhash function lookuplookup (key) → data insert (key, data) lookuplookup (key) → data insert (key, data) ““Beattles”Beattles” 22 h(key)%Nh(key)%N N-1
- 8. Distributed Hash Tables • Open Services [OpenDHT] • File sharing [CFS, OceanStore, PAST] • Web cache [Squirrel, Coral] • Censor-resistant stores [Eternity, FreeNet] • Application-layer multicast [Narada, Scribe] • Event notification [Scribe] • Streaming [SplitStream] • Naming systems [ChordDNS, INS] • Query and indexing [Kademlia] • Communication primitives [I3] • Backup store [HiveNet] • Web archive [Herodotus]
- 9. P2P euphoria • Diaspora • FreedomBox • Yacy Search engine • ArkOS • IPFS • BitTorrent • Wuala • Spotify • Skype
- 10. P2P decline
- 11. Problems of Open P2P Networks • Free riding and incentives • Performance problems due to instability, heterogeneity and churn • Security and fragility of open networks and peers • System Complexity and maintenance 11 Economical Rice Podcast
- 15. Blockchain euphoria • Initial Coin Offering (ICO) ● > 1000 (2018) ● Ethereum raised $18m in 2014 ● Block.one raised $4bn for the EOS blockchain ● Telegram raised $1.7bn for their cryptocurrency ● Tron bought the BitTorrent company for $140m ● FileCoin’s ICO received $200m million from accredited investors • Decentralized apps ● DTube (Decentralized Youtube) ● Graphite Docs (decentralized Google Docs) ● Hearth (decentralized Dropbox and Web hosting service) ● Props (decentralized video streaming) ● FileCoin (decentralized storage) ● OpenBazaar (decentralized eBay) 15
- 16. Problems of Permissionless Blockchain Networks • Incentives ● People are no longer mining Bitcoin on their home laptops ● The increasing resources required from participant nodes is expelling normal users • Performance ● Off-chain protocols, trusted groups, centralization, ... • Security and fragility ● Attacks: DAO, Ethereum Classic, Dapps and EVMs • System Complexity and maintenance ● Solidity, code complexity and size, updates 16
- 17. Problems of Permissionless Blockchain Networks • They cannot become a universal substrate for a decentralized Internet • Volatile cryptocurrencies cannot compete with Cloud stable pricing • Scalable services require disaggregation compute/storage, content distribution networks, and partitioned shared-nothing services 17
- 20. Edge-centric computing v2 20 The constant struggle between the forces of centralization and decentralization is inherent to the human nature and history. In the end, there is always a competition for power involving control and trust. In a centralized system, the participants must trust a central entity, which can effectively exercise control over them. In a decentralized system, both trust and control are spread between the participants.
- 21. Edge-centric Computing: Vision and Challenges 21
- 23. Permissioned Blockchains • Authenticated servers and controlled networks • Crash fault-tolerant (CFT) and byzantine fault tolerant (BFT) consensus protocols • Disentangled from Cryptocurrencies • Support for Smart contracts, decentralized Identity • Blockchain as a Service 23
- 24. Challenges • Hybrid architectures ● DPKI ? Solid ? • Blockchain islands • Interoperability ● Decentralized Identity • Control is in the edge • Trust is in the chains • Smart contracts ? 24
- 25. THANK YOU! This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 825184.