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![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', }](https://image.slidesharecdn.com/random-160703071203/75/Concept-of-BlockChain-Decentralized-Application-14-2048.jpg)
![Contract Code # $ var source = "contract SingleNumRegister { uint storedData; function set(uint x) { storedData = x; } function get() constant returns (uint retVal) { return storedData; }}" $ var sourceCompiled = eth.compile.solidity(source) # $ var contractAbiDefinition = sourceCompiled.SingleNumRegister.info.abiDefinition $ var sourceCompiledContract = eth.contract(contractAbiDefinition) $ var contract = sourceCompiledContract.new({from:eth.accounts[0], data: sourceCompiled.SingleNumRegister.code}) Node](https://image.slidesharecdn.com/random-160703071203/75/Concept-of-BlockChain-Decentralized-Application-34-2048.jpg)
![Contract Code # $ var cnt = eth.contract([{ constant: false, inputs: [{ name: 'x', type: 'uint256' } ], name: 'set', outputs: [ ], type: 'function' }, { constant: true, inputs: [ ], name: 'get', outputs: [{ name: 'retVal', type: 'uint256' } ], type: 'function' } ]).at(‘0x8ea277dfe4195daf7b8c101d79da35d1eb4c4aeb'); # $ cnt.set.sendTransaction(3,{from:eth.accounts[0]}) ‘0x979c4e413a647673632d74a6c8b7f5b25a3260f3fefa4abea2dc265d61215939' # $ cnt.get()](https://image.slidesharecdn.com/random-160703071203/75/Concept-of-BlockChain-Decentralized-Application-36-2048.jpg)
![Create a Digital Asset from bigchaindb import crypto # testuser1_priv, testuser1_pub = crypto.generate_key_pair() # digital_asset_payload = {'msg': 'Hello BigchainDB!'} # tx = b.create_transaction(b.me, testuser1_pub, None, 'CREATE', payload=digital_asset_payload) # tx_signed = b.sign_transaction(tx, b.me_private) # b.write_transaction(tx_signed) # tx_retrieved = b.get_transaction(tx_signed['id']) tx_retrieved](https://image.slidesharecdn.com/random-160703071203/75/Concept-of-BlockChain-Decentralized-Application-47-2048.jpg)
Uploaded bySeiji Takahashi
Concept of BlockChain & Decentralized Application
The document outlines the concept of blockchain and decentralized applications, detailing the technical components such as nodes, proofs of work and stake, and the Ethereum blockchain ecosystem. It includes examples of code for smart contracts in Solidity and instructions for setting up private Ethereum networks and utilizing BigchainDB alongside IPFS for decentralized storage. Additionally, it references various resources and installation guides for Ethereum and related technologies.
Concept of BlockChain & Decentralized Application
- 1. Concept of BlockChain & Decentralized Application timakin /@__timakin__ YAP(achimon)C::Asia Hachioji 2016 mid in Shinagawa
- 3. • github: timakin •twitter: @__timakin__ • DeNA -> Translimit • Go / Ruby / Node • Blog medium: https://medium.com/@timakin timekin.log: http://tech-savvy.hatenablog.com/
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- 12. Chain Flow hash target nonce transactionstransactions transactions blockblock block
- 13. Inside of blockchain •JSON JSON • nonce • parent hash hash
- 14. 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', }
- 15. Chain management • P2P Nodejson • Node
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- 17. Consensus Algorithm • Proofof 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
- 19. • • PoW 10 • • •PoS • • • Node •
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- 24. Decentralized Application P2P Node Permanent web
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- 26. Decentralized Application Processing File StorageDatabase Processing File Storage Database
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- 28. Euthareum Client • Geth(go-euthareum) Node
- 29. Install https://github.com/ethereum/go-ethereum OS # install euthareum $brew tap ethereum/ethereum $ brew install ethereum # install go, gmp $ brew install gmp go # install geth $ git clone https://github.com/ethereum/go-ethereum $ cd go-ethereum $ make geth
- 30. Build private network $mkdir /home/test_u/eth_private_net { "nonce": "0x0000000000000042", "timestamp": "0x0", "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000", "extraData": "0x0", "gasLimit": "0x8000000", "difficulty": "0x4000", "mixhash": "0x0000000000000000000000000000000000000000000000000000000000000000", "coinbase": "0x3333333333333333333333333333333333333333", "alloc": {} } Genesis
- 31. Connect to privatenetwork $ geth --networkid "10" --nodiscover --datadir "/home/test_u/ eth_private_net" --genesis "/home/test_u/eth_private_net/ myGenesis.json" console 2>> /home/test_u/eth_private_net/ geth_err.log # private 10 id # peer # console
- 32. Contract Code # Solidity $sudo add-apt-repository ppa:ethereum/ethereum $ sudo apt-get update $ sudo apt-get install solc $ brew install cpp-ethereum $ brew linkapps cpp-ethereum $ solc —-version $ which solc # solc geth $ admin.setSolc(“which solc path") $ eth.getCompilers() • • Ethereum Virtual Machine Euthareum • Solidity • IDE: https://github.com/ethereum/browser-solidity
- 33. Contract Code # Solidity contractSingleNumRegister { uint storedData; function set(uint x) { storedData = x; } function get() constant returns (uint retVal) { return storedData; } } Solidity JavaScript
- 34. Contract Code # $ varsource = "contract SingleNumRegister { uint storedData; function set(uint x) { storedData = x; } function get() constant returns (uint retVal) { return storedData; }}" $ var sourceCompiled = eth.compile.solidity(source) # $ var contractAbiDefinition = sourceCompiled.SingleNumRegister.info.abiDefinition $ var sourceCompiledContract = eth.contract(contractAbiDefinition) $ var contract = sourceCompiledContract.new({from:eth.accounts[0], data: sourceCompiled.SingleNumRegister.code}) Node
- 35. Contract Code $ contract { address:'0x8ea277dfe4195daf7b8c101d79da35d1eb4c4aeb', transactionHash: '0xeb76caefdfe5a9aa10b11743d317cf15f881d3b2e52ba3251dcf8e0718ed5b33' , allEvents: function (), get: function (), set: function () } # $ contractAbiDefinition
- 36. Contract Code # $ varcnt = eth.contract([{ constant: false, inputs: [{ name: 'x', type: 'uint256' } ], name: 'set', outputs: [ ], type: 'function' }, { constant: true, inputs: [ ], name: 'get', outputs: [{ name: 'retVal', type: 'uint256' } ], type: 'function' } ]).at(‘0x8ea277dfe4195daf7b8c101d79da35d1eb4c4aeb'); # $ cnt.set.sendTransaction(3,{from:eth.accounts[0]}) ‘0x979c4e413a647673632d74a6c8b7f5b25a3260f3fefa4abea2dc265d61215939' # $ cnt.get()
- 37. Run the appon EVM # RPC geth $ geth --networkid "10" --nodiscover --datadir "/home/test_u/ eth_private_net" --genesis "/home/test_u/eth_private_net/myGenesis.json" --mine --unlock 0xa7653f153f9ead98dc3be08abfc5314f596f97c6 --rpc --rpcaddr "192.168.5.6" --rpcport "8545" --rpccorsdomain "*" console 2>> /home/ test_u/eth_private_net/geth_err.log # meteor project $ cd ~/eth-test # $ meteor create simple-app # Meteor $ meteor add twbs:bootstrap $ meteor add ethereum:web3 $ meteor add ethereum:accounts $ meteor add ethereum:blocks EVM
- 38. Run the appon EVM # geth $ vim client/lib/init.js ``` //Web3 web3 = new Web3(); //RPC if(!web3.currentProvider) web3.setProvider(new web3.providers.HttpProvider("http://localhost: 8545")); // EthAccounts EthAccounts.init(); //EthBlocks EthBlocks.init(); ```
- 39. Run the appon EVM $ vim client/main.html ``` <head> <title>Simple Ether Wallet</title> </head> <body> <template name="nodeStatusComponent"> <div class="panel panel-default"> <div class="panel-heading"> <h4>Node Status</h4> </div> <table class="table"> <tbody> <tr> <th scope="row">Node</th> <td>{{currentProvider}}</td> </tr> <tr> <th scope="row">Is Mining?</th> <td>{{isMining}}</td> </tr> <tr> <th scope="row">Hashrate</th> <td>{{currentHashrate}}</td> </tr> <tr> <th scope="row">Peer Count</th> <td>{{currentPeerCount}}</td> </tr> </tbody> </table> </div> </template> ```
- 40. Run the appon EVM # $ vim client/main.html ``` <head> <title>Simple Ether Wallet</title> </head> <body> <template name="nodeStatusComponent"> <div class="panel panel-default"> <div class="panel-heading"> <h4>Node Status</h4> </div> <table class="table"> <tbody> <tr> <th scope="row">Node</th> <td>{{currentProvider}}</td> </tr> <tr> <th scope="row">Is Mining?</th> <td>{{isMining}}</td> </tr> <tr> <th scope="row">Hashrate</th> <td>{{currentHashrate}}</td> </tr> <tr> <th scope="row">Peer Count</th> <td>{{currentPeerCount}}</td> </tr> </tbody> </table> </div> </template> ```
- 41. Run the appon EVM # $ vim client/main.js ``` // nodeStatusComponent Template.nodeStatusComponent.helpers({ // currentProvider: function(){ return web3.currentProvider.host; }, // // true false isMining: function(){ return web3.eth.mining; }, // currentHashrate: function(){ return web3.eth.hashrate; }, // currentPeerCount: function(){ return web3.net.peerCount; } }); ``` meteor
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- 45. Install, Configuration # rethinkdbhttp://rethinkdb.com/docs/install/ # bigchainDB $ sudo pip install bigchaindb $ vim instance1.conf ``` server-tag=original directory=/data bind=all direct-io # Replace node?_hostname with actual node hostnames below, e.g. rdb.examples.com join=node0_hostname:29015 join=node1_hostname:29015 join=node2_hostname:29015 # continue until there's a join= line for each node in the federation ```
- 46. Run the BigChainDBserver # rethinkdb bigchaindb server $ rethinkdb --config-file path/to/instance1.conf $ bigchaindb init $ bigchaindb set-shards 1 $ bigchaindb set-replicas 1 $ bigchaindb start
- 47. Create a DigitalAsset from bigchaindb import crypto # testuser1_priv, testuser1_pub = crypto.generate_key_pair() # digital_asset_payload = {'msg': 'Hello BigchainDB!'} # tx = b.create_transaction(b.me, testuser1_pub, None, 'CREATE', payload=digital_asset_payload) # tx_signed = b.sign_transaction(tx, b.me_private) # b.write_transaction(tx_signed) # tx_retrieved = b.get_transaction(tx_signed['id']) tx_retrieved
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- 49. IPFS • • gateway RESTAPI curl • P2P
- 50. Install https://ipfs.io/docs/install/ go # $ ipfs init $ipfs daemon # peer $ ipfs swarm peers # ipfs image $ ipfs cat /ipfs/QmW2WQi7j6c7UgJTarActp7tDNikE4B2qXtFCfLPdsgaTQ/cat.jpg >cat.jpg $ open cat.jpg # localhost webui $ open http://localhost:5001/webui
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- 52. Upload assets # $ ipfsadd 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
- 53. 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
- 54. ex) gx-go https://github.com/whyrusleeping/gx-go ipfs version go package manager
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- 56. IPFS • • gateway RESTAPI curl • gateway (https://ipfs.io/ipfs/$hash) •
- 57. DApp • • DB Storage CDN BigChainDB PeerNode IPFS Peer Node Processing File Storage Database tr tr tr bb b bb b bb b
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- 60. • http://www.meti.go.jp/press/2016/04/20160428003/ 20160428003-2.pdf • http://www.slideshare.net/ks91020/ss-58535780 • 5 http://www.slideshare.net/cookle/5-58379474
- 61. • Ethereum-WhitePaper-JP https://github.com/kurihei/Ethereum-WhitePaper-JP/blob/master/%5BJapanese%5D-White- Paper.md •Ethereum Specification https://github.com/ethereum/go-ethereum/wiki/Ethereum-Specification • Gitbook Ethereum https://www.gitbook.com/book/a-mitani/mastering-ethereum/details • BigchainDB: how we built a blockchain database on top of RethinkDB https://speakerdeck.com/vrde/bigchaindb-how-we-built-a-blockchain-database-on-top-of-rethinkdb • White Paper: BigchainDB: A Scalable Blockchain Database(DRAFT) https://www.bigchaindb.com/whitepaper/bigchaindb-whitepaper.pdf • White Paper: IPFS - Content Addressed, Versioned, P2P File System (DRAFT 3) https://ipfs.io/ipfs/QmR7GSQM93Cx5eAg6a6yRzNde1FQv7uL6X1o4k7zrJa3LX/ipfs.draft3.pdf
- 62. • OSS Go Go •Docs White Paper pdf • • Euthareum Github Github