Understanding private blockchains
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This document discusses private blockchains and how they differ from public blockchains. It explains that private blockchains are permissioned shared databases that use blockchain technology like cryptography and consensus algorithms to provide trust between entities that have limited trust. While they don't have the same properties as public blockchains like immutability and anonymity, private blockchains can enable use cases like financial settlement, provenance tracking, and interorganizational record keeping where a centralized database is not ideal due to lack of trust or need for disintermediation. The document addresses criticisms of private blockchains and blockchain technology in general. It also introduces the MultiChain platform for deploying private blockchains.
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Understanding private blockchains
- 1. Understanding private blockchains Dr Gideon Greenspan, Founder and CEO
- 2. A brief history of blockchains 2009 Bitcoin 2011—2013 Altcoins 2015— Many private blockchains http://corporate.comcast.com/comcast-voices/comcast-sponsors-internet-measurement-hackathon
- 3. Public blockchains in enterprises? • Low capacity • Poor governance • Unknown costs • Anonymous miners • Cryptocurrencies • Writable by all • Visible to all • One bloated ledger
- 4. Blockchains for enterprises • Private shared database • Byzantine fault tolerance • Control of capacity + cost • Designated “miners” • No cryptocurrency • Collective admin • Blockchain as tool not ideology
- 5. Tomato 1 This is just a shared database!
- 8. Peer-to-peer shared databases Node Node Node NodeTransaction Block Blockchain Consensus created by validator nodes
- 9. Peer-to-peer DB requirements • Atomic transactions – Self-contained “packets” • Peer-to-peer ⇒ origin unknown – Transactions digitally signed – All data tagged by public key/s • Shared write ⇒ transaction constraints – Bitcoin vs Ethereum style • Consensus mechanism
- 10. Signed by Bob Signed by Alice Alice £10 Bob $15 Alice $15 Bob £10 Bitcoin-style constraints Metadata: b469dc12a0746…
- 11. Ethereum-style constraints from = msg.sender fromvalue = contract.storage[from] to = msg.data[0] value = msg.data[1] if fromvalue >= value: contract.storage[from] -= value contract.storage[to] += value return(1) else: return(0)
- 12. A new type of shared database
- 13. Tomato 2 This is not immutable!
- 14. “Mining” in private chains • All blocks signed by miner • Only permitted miners ü No impersonation attacks • Mining diversity constraint ü Proof of work not required
- 15. On immutability • Public blockchains – Secured by hashing power – Mutable by 51% of hashrate – Threat: someone rich (e.g. a government) • Private blockchains – Secured by distributed consensus – Mutable by ≥51% of validators – Threat: validator collusion
- 16. Tomato 3 This is not a blockchain!
- 17. Public vs private blockchains Different Same Permissions model Peer-to-peer architecture Transaction censorship Byzantine fault tolerance Native cryptocurrency Public key cryptography “The blockchain” Transaction constraints Proof-of-work consensus Consensus chain of blocks
- 18. Public vs private blockchains Different Same Permissions model Peer-to-peer architecture Transaction censorship Byzantine fault tolerance Native cryptocurrency Public key cryptography “The blockchain” Transaction constraints Proof-of-work consensus Consensus chain of blocks
- 19. Philosophical Investigations “the meaning of a word is its use in the language” — LW
- 20. Tomato 4 This has no uses!
- 21. What are blockchains for? • Old problem: – Shared database (or ledger) – Multiple writers – Limited trust • Old solution: – Centralized database at intermediary • New possibility: – Use a (private) blockchain
- 22. Blockchains vs centralized DBs Advantages Disadvantages Disintermediation Confidentiality Robustness Performance
- 23. Post-trade settlement? • Interbank blockchain • Issue any asset on chain • Rapid settlement • Delivery versus payment • No need for reconciliation • Regulatory transparency
- 24. Post-trade settlement? • Interbank blockchain • Issue any asset on chain • Rapid settlement • Delivery versus payment • No need for reconciliation • Regulatory transparency Confidentiality
- 25. Strong blockchain use cases • Lightweight financial systems • Provenance tracking • Interorganizational record keeping – Multiparty data aggregation
- 26. Lightweight finance • Any asset can be tokenized on blockchain – Tokens issued by trusted entity/s – Token confers right of redemption • Disintermediates centralized control – More secure and cheaper • Confidentiality limits applications – Small financial trading circles – Gift cards, loyalty points
- 27. Provenance tracking • Digital certificate of authenticity – Physical transfer ⇒ token transfer – Verifiable chain of custody • Disintermediates risk of fraud – Collusion cannot corrupt • Confidentiality via multiple addresses – Fewer transactions between competitors – Regulation can still be a concern
- 29. Interorganizational records • Collectively record and notarize – Communications or transactions – Digital signatures + immutability • Infrastructure solution for large groups • Disintermediates external party – Cheaper and simpler • Confidentiality easily addressed – Encryption or hashing
- 30. Tomato 5 This is nothing new!
- 32. New? Bitcoin transaction model http://qiita.com/yanagisawa-kentaro/items/503dfce3762e3b1237c9
- 33. New? Compact state proofs https://blog.ethereum.org/2015/11/15/merkling-in-ethereum/
- 34. New: Awareness + Productization
- 38. Tomato 7 This is all vaporware!
- 39. MultiChain blockchain platform • Off-the-shelf private blockchains ü Easy to configure and deploy • Permission management ü Private and tightly controlled • Native asset support ü Tracked at network level • Extendable via metadata ü Up to 8MB arbitrary data per transaction
- 41. Questions? Visit www.multichain.com for: MultiChain download Getting started guide Developer docs and forum Popular private blockchain blog