TDC SP 2019 - Trilha Blochchain - Algoritmos de Consenso

Blockchain - Consensus Algorithms presentation by Leonardo Piedade.

Transcript

1. Globalcode – Open4education Blockchain – Algoritmos de Consenso Consensus Algorithms Leonardo Piedade
2. Globalcode – Open4education Speaker Leonardo Piedade - 15+ years programming - 12+ years developing using Java - BS Degree in Computer Science - Web, Integration Systems, Backend, Distributed Systems and Blockchain Platforms. leoabrahao@gmail.com
3. Globalcode – Open4education The Trust Machine “It is the first, full consensus distributed ledger mankind has ever seen” – Mastering Blockchain about Bitcoin https://www.economist.com/leaders/2015/10/31/the-trust-machine
4. Globalcode – Open4education https://www.technologyreview.com/s/610781/in-blockchain-we-trust/
5. Globalcode – Open4education Blockchain Principles Distributed Ledger Technology Data, assets, records, etc... Immutable transactions Everybody has a copy P2P Network Partial or Fully Distributed Consensus Untrusted Nodes Economic Model
6. Globalcode – Open4education Network Models Central Intermediary Competing Intermediaries No Intermediary (aka P2P)
7. Globalcode – Open4education “More precisely it is a decentralized distributed system” – Bitcoin In The Crypto World…
8. Globalcode – Open4education
9. Globalcode – Open4education CAP Theorem “Consistency is sacrificed in favor of availability and partition tolerance. But consistency is achieved over time” – Mastering Blockchain https://towardsdatascience.com/cap-theorem-and-distributed-database-management-systems-5c2be977950e ONLY PICK 2 OF THE 3!
10. Globalcode – Open4education Double Spending
11. Globalcode – Open4education “consensus algorithms exist to prevent double spending.” In The Crypto World…
12. Globalcode – Open4education “general agreement; harmony.” con
    sen
    sus /kənˈsen.səs/
13. Globalcode – Open4education “It is a process of agreement between distrusting nodes on a final state of data.” Consensus
14. Globalcode – Open4education The Two Generals Problem - 1975 https://www.youtube.com/watch?v=s8Wbt0b8bwY “Proved to be unsolved” https://mwhittaker.github.io/blog/two_generals_and_time_machines/
15. Globalcode – Open4education The Byzantine Generals Problem - 1982 https://people.eecs.berkeley.edu/~luca/cs174/byzantine.pdf “It can reach consensus as long as 2/3 are honest” - Lamport https://www.youtube.com/watch?v=dfsRQyYXOsQ
16. Globalcode – Open4education Fault Tolerance “The consensus algorithm should be able to run in the presence of faulty or malicious nodes.”
17. Globalcode – Open4education Classical Consensus “Every participant gets one vote” Examples: Paxos, Practical Byzantine Fault Tolerance (PBFT)
18. Globalcode – Open4education Classical Consensus “Problem: Who is a Participant?” Possible Solution: One IP address = One Vote?
19. Globalcode – Open4education Sybil Attack https://www.microsoft.com/en-us/research/wp-content/uploads/2002/01/IPTPS2002.pdf
20. Globalcode – Open4education
22. Globalcode – Open4education Classical Consensus Requires a Closed Network https://www.imdb.com/title/tt3531824
23. Globalcode – Open4education Classical Consensus Requires a Closed Network
26. Globalcode – Open4education Proof of Work (PoW) - 2009 “Proof-of-work is essentially one-CPU-one-vote” - Bitcoin whitepaper Examples: Bitcoin(*), Ethereum, Dogecoin, Litecoin, Zcash, Monero, Dash, Primecoin, Verge, Tether
29. Globalcode – Open4education Proof of Work (PoW)
30. Globalcode – Open4education Proof of Work (PoW)
31. Globalcode – Open4education Proof of Work (PoW)
32. Globalcode – Open4education
34. Globalcode – Open4education
36. Globalcode – Open4education Attacks “As long as a majority of CPU power is controlled by nodes that are not cooperating to attack the network, they'll generate the longest chain and outpace attackers.” – Bitcoin whitepaper https://bitcoin.org/bitcoin.pdf
37. Globalcode – Open4education 51% Attack or Double-Spend Attack https://medium.com/coinmonks/what-is-a-51-attack-or-double-spend-attack-aa108db63474
38. Globalcode – Open4education 51% Attack or Double-Spend Attack https://medium.com/coinmonks/what-is-a-51-attack-or-double-spend-attack-aa108db63474
39. Globalcode – Open4education 51% Attack
40. Globalcode – Open4education 51% Attack Myths https://www.binance.vision/pt/security/what-is-a-51-percent-attack
41. Globalcode – Open4education https://www.crypto51.app/
42. Globalcode – Open4education “Houston we have a problem.”
43. Globalcode – Open4education Mining Pools https://www.blockchain.com/pools 07/15/2019
44. Globalcode – Open4education Proof of Stake (PoS) Examples: Cardano (Ouroboros), Nxt, Blackcoin, Peercoin “Everyone gets to vote proportional to their wealth” https://www.youtube.com/watch?v=psKDXvXdr7k Randomized Block Selection Coin Age Selection
45. Globalcode – Open4education Delegated Proof of Stake (DPoS) – 2014 Examples: EOS, BitShares, Steem, Lisk, Ark Digital Democracy Votes are proportional to the currencies Faster alternative Delegates vs Network Speed https://www.youtube.com/watch?v=OVKAOwzAwHI
46. Globalcode – Open4education “Don't do it, if you can avoid it.” Public Networks?
47. Globalcode – Open4education Practical Byzantine Fault Tolerance (PBFT) - 1999 http://pmg.csail.mit.edu/papers/osdi99.pdf Examples: Corda*, Hyperledger*, Neo*, Quorum* Closed networks Leader-based Full peering
48. Globalcode – Open4education The Byzantine Fault Tolerance http://www.csl.sri.com/papers/emsoft01/emsoft01.pdf
49. Globalcode – Open4education The Byzantine Fault Tolerance https://lwn.net/Articles/540368/
50. https://developers.libra.org/docs/assets/papers/the-libra-blockchain.pdf
51. Globalcode – Open4education Facebook LibraBFT Libra HotStuff https://developers.libra.org/docs/assets/papers/libra-consensus-state-machine-replication-in-the-libra-blockchain.pdf https://www.cs.unc.edu/~reiter/papers/2019/PODC.pdf
52. Globalcode – Open4education Some “Mastering” books…
53. Globalcode – Open4education …and whitepapers https://arxiv.org/pdf/1711.03936.pdf https://arxiv.org/pdf/1904.03487.pdf https://www.bitcoil.co.il/Doublespend.pdf
54. https://blog.acolyer.org/2018/02/12/sok-consensus-in-the-age-of-blockchains/
55. Globalcode – Open4education Go further Proof of Activity Proof of Authority Proof of Burn Proof of Capacity/Space Proof of Deposit Proof of Elapsed Time Proof of Importance Proof of Storage Delayed Proof of Work PAXOS RAFT Tangle FBA Casper FFG Casper CBC Hashgraph
56. Globalcode – Open4education … download this! bit.ly/tdcsp-2019 Leonardo Piedade
57. linkedin.com/in/leoap github.com/lpiedade leoabrahao@gmail.com