Blockchain on Go

Blockchain on Go

1. 1. BlockChain on Go @__timakin__ / DevFest Tokyo 2017
2. 2. • • Github: timakin / Twitter: @__timakin__ • Gunosy Inc. • Go / Swift • community • golang.tokyo • roppongi-golunch • blockchain.tokyo
3. 3. golangtokyo.connpass.com
4. 4. • Blockchain • Go Blockchain
5. 5. Blockchain • • -> JSON • P2P
6. 6. Chain Flow hash target nonce transactions transactions transactions blockblock block
7. 7. Example of block { difficulty: '137447', extraData: '0x476574682f76312e302e312f6c696e75782f676f312e342e32', gasLimit: 3141592, gasUsed: 0, hash: '0x4d3063b91cbaa12bf2de81014c1319febc9f197c93f81b0746afaffaa9496620', nonce: '0x28fda83cb19ed497', number: 100, parentHash: '0x5885cdec1d1410580eaaf1fb7ef9db245a735822d48e816c73d926b7c9872f15', size: 536, timestamp: 1439451765, totalDifficulty: '13551548', transactions: [ ], transactionsRoot: '0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421', }
8. 8. Consensus Algorithm • Proof of Work • Node 0 
 Node • target nonce(hash value) • Node 
 
 • Proof of Stake • • ex) SHA256(prevhash + address + timestamp) <= 2^256 * balance (volume of stake) / diff • 
 Proof of Stake Velocity
9. 9. Decentralized Application Processing File Storage Database Processing File Storage Database
10. 10. • • • • • • ms •
11. 11. • • 2017/10/1 135GB •
12. 12. • • Bitcoin Ethereum • • Read/Write
13. 13. • ms • •
14. 14. http://blockchaindemo.io/
15. 15. Go Blockchain • Go C++ Python • Go
16. 16. Go? • • • •
17. 17. btcd • Bitcoin fork • bitcoin/bitcoin C++ • libbitcoin(C++), BitcoinJ(Java) • • JSON-RPC API 

18. 18. geth(go-ethereum) • Go • Ethereum protocol Go • Ethereum • Windows OS • geth( 7832) cpp-ethereum( 1710), pythereum( 1487), ethereumj(760)
19. 19. Ethereum 
 (geth) 
 P2P Network +
20. 20. Mist Wallet
21. 21. https://ethstats.net/
22. 22. HyperLedger • • Supported by The Linux Foundation • • IBM Intel J.P.Morgan MUFG NEC etc…
23. 23. HyperLedger ref: http://gaiax-blockchain.com/hyperledger-project
24. 24. HyperLedger Projects Fabric PBFT 
 
 
 * 
 * http://www.jpx.co.jp/corporate/research-study/working-paper/tvdivq0000008q5y-att/ JPX_working_paper_No15.pdf

25. 25. HyperLedger Fabric Network ref: https://www.ibm.com/developerworks/jp/cloud/library/j_cl-blockchain-basics-bluemix/
26. 26. PBFT (Practical Byzantine Fault Tolelance) ref: https://www.ibm.com/developerworks/jp/cloud/library/j_cl-blockchain-basics-bluemix/
27. 27. ChainCode • Go Java
28. 28. ChainCode
29. 29. World State • ChainCode R/W KVS JSON • ChainCode
30. 30. shim.ChaincodeStubInterface • chaincode WorldState Ledger API • Init, Invoke • Get/Put/Delete State World State • shim.Success, shim.Error res payload writer 200, 400, 500
31. 31. HyperLedger Composer Fabric Web IDE
32. 32. HyperLedger Composer Web UI (Fabric) 4 Model: Access Control: Read/Write Script: JS Query: Model REST API
33. 33. IPFS • P2P • Blockchain • • ipfs.pics Gyazo Winny
34. 34. Upload assets # $ ipfs add test.jpg added QmaC9pUA3grWJ948u1VWRLG1wPLP8YZe7b3HopBGk4zZyA test.jpg $ ipfs cat /ipfs/QmaC9pUA3grWJ948u1VWRLG1wPLP8YZe7b3HopBGk4zZyA > butaman.jpg $ open https://ipfs.io/ipfs/QmaC9pUA3grWJ948u1VWRLG1wPLP8YZe7b3HopBGk4zZyA # $ ipfs add -r ~/myproject # Fuse $ ipfs mount $ ls /ipfs/$hash/ # $ ipfs add -q test.mp4
35. 35. API Client var ipfs = require('ipfs-client'); var stream = ipfs.cat('QmTE9Xp76E67vkYeygbKJrsVj8W2LLcyUifuMHMEkyRfUL'); stream.pipe(process.stdout); ipfs.add(process.stdin, function(err, hash) { console.log(hash); }); https://www.npmjs.com/package/ipfs-client API Scala Go JavaScript
36. 36. WebUI
37. 37. • Go C++ • API CLI • WebUI