concept of blockchain & decentralized application
TRANSCRIPT
Concept of BlockChain
& Decentralized
Application
timakin / @__timakin__
YAP(achimon)C::Asia Hachioji 2016 mid in Shinagawa
• github: timakin
• twitter: @__timakin__
• DeNA -> Translimit
• Go / Ruby / Node
• Blogmedium: https://medium.com/@timakin timekin.log: http://tech-savvy.hatenablog.com/
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P2P
P2P
Chain Flow
hash
target nonce
transactions transactions transactions
blockblock block
Inside of blockchain
• JSON
JSON
•
nonce
• parent hash
hash
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',}
Chain management• P2P
Node json
• Node
A
B
C
fork
Consensus Algorithm• Proof of Work
• Node 0
Node
• target nonce(hash value)
• Node
• Proof of Stake
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• ex) SHA256(prevhash + address + timestamp) <= 2^256 * balance (volume of stake) / diff
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Proof of Stake Velocity
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• PoW
10
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• PoS
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• Node
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DApp Stack
Decentralized ApplicationP2P Node
Permanent web
Decentralized Application
Processing
File Storage Database
Decentralized Application
Processing
File Storage Database
Processing
File Storage Database
Euthareum
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•
ether
Euthareum Client
• Geth (go-euthareum)
Node
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
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
Connect to private network
$ 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
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
Contract Code
# Solidity
contract SingleNumRegister { uint storedData; function set(uint x) { storedData = x; } function get() constant returns (uint retVal) {
return storedData; }}
Solidity JavaScript
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
Contract Code$ contract{ address: '0x8ea277dfe4195daf7b8c101d79da35d1eb4c4aeb', transactionHash: '0xeb76caefdfe5a9aa10b11743d317cf15f881d3b2e52ba3251dcf8e0718ed5b33', allEvents: function (), get: function (), set: function ()}
# $ contractAbiDefinition
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()
Run the app on 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
Run the app on EVM# geth$ vim client/lib/init.js
```//Web3web3 = new Web3();
//RPCif(!web3.currentProvider) web3.setProvider(new web3.providers.HttpProvider("http://localhost:8545"));
// EthAccountsEthAccounts.init();
//EthBlocksEthBlocks.init();```
Run the app on 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>```
Run the app on 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>```
Run the app on EVM# $ vim client/main.js
```// nodeStatusComponentTemplate.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
Euthareum•
• Euthareum
BigChainDB
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• key-value
JSON
• python
BigChainDB
RethinkDB
BigChainDB
https://speakerdeck.com/vrde/bigchaindb-how-we-built-a-blockchain-database-
on-top-of-rethinkdb
Install, Configuration# rethinkdb http://rethinkdb.com/docs/install/
# bigchainDB$ sudo pip install bigchaindb$ vim instance1.conf``` server-tag=originaldirectory=/databind=alldirect-io# Replace node?_hostname with actual node hostnames below, e.g. rdb.examples.comjoin=node0_hostname:29015join=node1_hostname:29015join=node2_hostname:29015# continue until there's a join= line for each node in the federation ```
Run the BigChainDB server# rethinkdb bigchaindb server$ rethinkdb --config-file path/to/instance1.conf$ bigchaindb init$ bigchaindb set-shards 1$ bigchaindb set-replicas 1$ bigchaindb start
Create a Digital Assetfrom 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
BigChainDB
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• key-value RethinkDB
IPFS
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• gateway REST API
curl
• P2P
Installhttps://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
WEBUI
Upload assets# $ ipfs add test.jpgadded 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
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
ex) gx-gohttps://github.com/whyrusleeping/gx-go
ipfs version
go package manager
ex) ipfs-picshttps://ipfs.pics/
ipfs
script
DApp•
• DB Storage
CDN
BigChainDB
Peer Node IPFS
Peer Node
Processing
File Storage Databasetr tr tr
bb b
bb b bb b
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• P2P
CDN
• Node
Client-Server
• or <
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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
• 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
• OSS
Go Go
• Docs White Paper
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• Euthareum
Github
Github
