Blockchain daodac

1.

what is Ethereum:

Ethereum is an innovation based on the application of technologies and concepts in bitcoin to computers. Ethereum itself imitates a lot of bitcoin technology to maintain the computer platform. blockchain technology is one of them
Ethereum platform can safely run any program users want

advantages of Ethereum over other competitive currencies before Ethereum appeared, some digital currencies imitated bitcoin. However, these projects have their own shortcomings, they can only support one or several specific applications at the same time< However, the reason why Ethereum can surpass the limitations of these projects in the past is because of the core idea of Ethereum

what Ethereum wants to implement is a blockchain protocol with built-in programming language. Since it supports programming language, in theory, any blockchain application can be defined with this language, and then run on Ethereum's blockchain protocol as an application

The design of Ethereum is very flexible and adaptable

Ethereum target sets the advantages of blockchain technology, in order to add the advantages of blockchain, such as decentralization, openness and security, to almost all computing fields

blockchain applications of Ethereum

Ethereum has many blockchain applications, such as digital applications of gold and stocks, financial derivatives applications, DNS and digital authentication, etc

Ethereum has achieved more than 100 blockchain applications by many start-ups

Ethereum has also been closely watched by some financial institutions, banking consortia (such as R3), as well as large companies like Samsung, Deloitte, RWE and IBM. As a result, a number of blockchain applications such as simplified and automated financial transactions, merchant loyalty index tracking, and gift cards designed to achieve decentralization of electronic transactions have emerged

the relationship between Ethereum and blockchain:

Ethereum is a programmable blockchain

Ethereum does not give users a series of preset operations (such as bitcoin transaction), but allows users to create complex operations according to their own wishes

in this way, Ethereum can be used as a platform for various types of decentralized blockchain applications, including but not limited to cryptocurrency

like other blockchains, Ethereum also has a peer-to-peer network protocol. Ethereum blockchain database is maintained and updated by many nodes connected to the network. Each network node runs the Ethereum simulator and executes the same instructions. Therefore, people sometimes call Ethereum "world computer"

2. The pain point of asset securitization business is that the authenticity of underlying assets cannot be guaranteed; There are many participants, many operation links and low transparency of transactions, resulting in information asymmetry and other problems, which makes it difficult to control the risks. The data pain points lie in the low efficiency of the flow among the participants, the large amount of manpower and material resources needed for the fund clearing and reconciliation between the transaction systems of all parties, the online and offline multiple channels of asset collection, and the inability to monitor the real situation of the assets. There are also problems of trust in the authenticity and accuracy of the underlying asset data of all parties in the transaction chain after the formation of the asset package

Change: the characteristics of blockchain disintermediation, consensus mechanism and non tampering can increase the efficiency of data flow, rece costs, monitor the real situation of assets in real time, and ensure the trust of all parties in the transaction chain on the underlying assets.

3. Users can use "dagt" token or "usdt" token to pay the credit service fee, so as to obtain dagt capital services.

4. One party: dagt pass holders, and users who use their own digital assets to initiate loan credit qualification applications
· users who are optimistic about the future of digital assets and hope to hold them for a long time, but have short-term and medium-term liquidity needs
two parties: dagt Foundation (non-profit), which is responsible for the R & D, operation and promotion of dagt projects
· based on blockchain technology, Provide digital asset loan credit service for credit users
tripartite: refers to institutions that comply with relevant national laws and have loan qualification, such as banks, online loan companies, small loan companies, etc.
· dagt system will realize system docking with third-party loan institutions

5.

On the morning of May 28, a special actor played Mao Zedong to participate in the 2018 Boao Asian blockchain forum. The video was forwarded in the circle of friends. In his speech, the actor said, "I thank you in the name of Mao Zedong.". According to the information of the organizer, the organizing committee includes panda capital and other investment institutions, and the activity is supported by Martian finance and other blockchain media. Beijing News reporter learned that panda capital and Mars finance and economics issued clarification statements afterwards, saying that they did not participate in the activities or cooperate with the forum. At the same time, the Organizing Committee announced that the actor's speech does not represent the organizing committee, but is only a part of the performance

according to the notice on prohibiting the use of the image of Party and state leaders for commercial promotion issued by the State Administration for Instry and commerce, it is prohibited to use and display the image and inscription of Party and state leaders (including those who have left or died) on commodities and their packages, as well as any form of expression involving the name of Party and state leaders; It is forbidden for enterprises to use the name and image of the party and state leaders to carry out any form of commercial propaganda and promotion activities. They are not allowed to use the images and inscriptions of the party and state leaders (including those who have left or died), or use special actors to promote procts or services with the image of the leaders

content source: Beijing News

6. 1、 Similarity

distributed
git ensures that each code warehouse maintains a complete project library locally, not just the branch in which it works and its own submission history. At the same time, it also keeps all the snapshot and index information after the latest pull

on the blockchain, each node keeps a complete database locally, not just its own transaction information

traceability
in Git commit chain, each commit object contains a parent object (the object of the last commit, except the first commit), which can trace all the previous records

on the blockchain, each block contains the index of the previous block (except the genesis block), which can trace all valid transactions before<

tamper proof
in Git's commit chain, each object itself calculates a checksum before storing, and then references it with a checksum. Once modified, the checksums will not be correct, which means that it is impossible to change the contents of any file or directory without git's knowledge< The mechanism used by git to calculate the checksums is called SHA-1 hash. This is a string composed of 40 hexadecimal characters (0-9 and A-F), which is calculated based on the content or directory structure of the file in GIT. SHA-1 hash looks like this:



in the blockchain, each block contains the last block ID, and this block ID has two SHA-256 hashes, which are calculated based on the block content. Once the content is modified, the hash will change, which is inconsistent with the chain of other nodes and cannot be added to the longest chain, so the content cannot be tampered with< 2. Difference

collective consensus and central node will: 1 - blockchain merges based on collective consensus (POW / POS) to form the longest chain, which is the main chain

2 - in Git system, when multi node cooperation is carried out through the warehouse hosting platform, it is the manager of the platform project who controls the power of merge, which reflects the will of the central node<

cryptography
1 - in bitcoin blockchain, cryptography mainly uses the following methods

in the whole system of bitcoin blockchain, a large number of public encryption algorithms are used, such as Merkle tree hash number algorithm, elliptic curve algorithm, hash algorithm, symmetric encryption algorithm and some coding algorithms. The functions of various algorithms in bitcoin blockchain are as follows:

A) hash algorithm

the two hash functions used in bitcoin system are: 1. SHA-256, which is mainly used to complete pow (proof of workload) calculation; 2. Ripemd160, mainly used to generate bitcoin address

b) Merkle hash tree

binary tree or multi tree based on hash value. In the computer field, Merkle tree is mostly used for integrity verification. In the distributed environment, integrity verification can greatly rece the complexity of data transmission and calculation<

C) elliptic curve algorithm

in bitcoin, the public key cryptography algorithm based on secp256k1 elliptic curve mathematics is used for signature and verification. On the one hand, it can ensure that the user's account is not replaced by an impostor, on the other hand, it can ensure that the user can not deny the signed transaction. The private key is used to sign the transaction information, and the user's public key is used to verify the signature. If the verification is passed, the transaction information will be recorded and the transaction will be completed

d) symmetric encryption algorithm

the official bitcoin client uses AES (symmetric block cipher algorithm) to encrypt the wallet file. After the user sets the password, the private key of the wallet is encrypted by the user set password through AES to ensure the security of the private key of the client

e) base58 encoding

base58 is a unique encoding method used in bitcoin. It is mainly used to generate the wallet address of bitcoin, which is similar to the permutation algorithm mechanism in classical cryptography. Its purpose is to increase the readability of bitcoin and change the binary hash value into the address we see

2 - git: SSH key is mainly used for remote login verification, SHA-1 is used for code content checking sum<

SSH is the abbreviation of secure shell, developed by IETF's network working group. It is a protocol designed to provide security for remote login sessions and other network services. SSH protocol can effectively prevent information leakage in the process of remote management< The process of SSH transmission is as follows: (1) the remote host receives the user's login request and sends its public key to the user 2) The user uses the public key to encrypt the login password and send it back 3) The remote host uses its own private key to decrypt the login password. If the password is correct, the user is allowed to log in.

7. <span style="font-family:Arial, Helvetica, sans-serif;">'use strict';</span>var CryptoJS = require("crypto-js");var express = require("express");var bodyParser = require('body-parser');var WebSocket = require("ws");var http_port = process.env.HTTP_PORT || 3001;var p2p_port = process.env.P2P_PORT || 6001;var initialPeers = process.env.PEERS ? process.env.PEERS.split(',') : [];class Block { constructor(index, previousHash, timestamp, data, hash) { this.index = index; this.previousHash = previousHash.toString(); this.timestamp = timestamp; this.data = data; this.hash = hash.toString(); }}var sockets = [];var MessageType = { QUERY_LATEST: 0, QUERY_ALL: 1, RESPONSE_BLOCKCHAIN: 2};var getGenesisBlock = () => { return new Block(0, "0", 1465154705, "my genesis block!!", "");};var blockchain = [getGenesisBlock()];var initHttpServer = () => { var app = express(); app.use(bodyParser.json()); app.get('/blocks', (req, res) => res.send(JSON.stringify(blockchain))); app.post('/mineBlock', (req, res) => { var newBlock = generateNextBlock(req.body.data); addBlock(newBlock); broadcast(responseLatestMsg()); console.log('block added: ' + JSON.stringify(newBlock)); res.send(); }); app.get('/peers', (req, res) => { res.send(sockets.map(s => s._socket.remoteAddress + ':' + s._socket.remotePort)); }); app.post('/addPeer', (req, res) => { connectToPeers([req.body.peer]); res.send(); }); app.listen(http_port, () => console.log('Listening http on port: ' + http_port));};var initP2PServer = () => { var server = new WebSocket.Server({port: p2p_port}); server.on('connection', ws => initConnection(ws)); console.log('listening websocket p2p port on: ' + p2p_port);};var initConnection = (ws) => { sockets.push(ws); initMessageHandler(ws); initErrorHandler(ws); write(ws, queryChainLengthMsg());};var initMessageHandler = (ws) => { ws.on('message', (data) => { var message = JSON.parse(data); console.log('Received message' + JSON.stringify(message)); switch (message.type) { case MessageType.QUERY_LATEST: write(ws, responseLatestMsg()); break; case MessageType.QUERY_ALL: write(ws, responseChainMsg()); break; case MessageType.RESPONSE_BLOCKCHAIN: handleBlockchainResponse(message); break; } });};var initErrorHandler = (ws) => { var closeConnection = (ws) => { console.log('connection failed to peer: ' + ws.url); sockets.splice(sockets.indexOf(ws), 1); }; ws.on('close', () => closeConnection(ws)); ws.on('error', () => closeConnection(ws));};var generateNextBlock = (blockData) => { var previousBlock = getLatestBlock(); var nextIndex = previousBlock.index + 1; var nextTimestamp = new Date().getTime() / 1000; var nextHash = calculateHash(nextIndex, previousBlock.hash, nextTimestamp, blockData); return new Block(nextIndex, previousBlock.hash, nextTimestamp, blockData, nextHash);};var calculateHashForBlock = (block) => { return calculateHash(block.index, block.previousHash, block.timestamp, block.data);};var calculateHash = (index, previousHash, timestamp, data) => { return CryptoJS.SHA256(index + previousHash + timestamp + data).toString();};var addBlock = (newBlock) => { if (isValidNewBlock(newBlock, getLatestBlock())) { blockchain.push(newBlock); }};var isValidNewBlock = (newBlock, previousBlock) => { if (previousBlock.index + 1 !== newBlock.index) { console.log('invalid index'); return false; } else if (previousBlock.hash !== newBlock.previousHash) { console.log('invalid previoushash'); return false; } else if (calculateHashForBlock(newBlock) !== newBlock.hash) { console.log(typeof (newBlock.hash) + ' ' + typeof calculateHashForBlock(newBlock)); console.log('invalid hash: ' + calculateHashForBlock(newBlock) + ' ' + newBlock.hash); return false; } return true;};var connectToPeers = (newPeers) => { newPeers.forEach((peer) => { var ws = new WebSocket(peer); ws.on('open', () => initConnection(ws)); ws.on('error', () => { console.log('connection failed') }); });};var handleBlockchainResponse = (message) => { var receivedBlocks = JSON.parse(message.data).sort((b1, b2) => (b1.index - b2.index)); var latestBlockReceived = receivedBlocks[receivedBlocks.length - 1]; var latestBlockHeld = getLatestBlock(); if (latestBlockReceived.index > latestBlockHeld.index) { console.log('blockchain possibly behind. We got: ' + latestBlockHeld.index + ' Peer got: ' + latestBlockReceived.index); if (latestBlockHeld.hash === latestBlockReceived.previousHash) { console.log("We can append the received block to our chain"); blockchain.push(latestBlockReceived); broadcast(responseLatestMsg()); } else if (receivedBlocks.length === 1) { console.log("We have to query the chain from our peer"); broadcast(queryAllMsg()); } else { console.log("Received blockchain is longer than current blockchain"); replaceChain(receivedBlocks); } } else { console.log('received blockchain is not longer than received blockchain. Do nothing'); }};var replaceChain = (newBlocks) => { if (isValidChain(newBlocks) && newBlocks.length > blockchain.length) { console.log('Received blockchain is valid. Replacing current blockchain with received blockchain'); blockchain = newBlocks; broadcast(responseLatestMsg()); } else { console.log('Received blockchain invalid'); }};var isValidChain = (blockchainToValidate) => { if (JSON.stringify(blockchainToValidate[0]) !== JSON.stringify(getGenesisBlock())) { return false; } var tempBlocks = [blockchainToValidate[0]]; for (var i = 1; i < blockchainToValidate.length; i++) { if (isValidNewBlock(blockchainToValidate[i], tempBlocks[i - 1])) { tempBlocks.push(blockchainToValidate[i]); } else { return false; } } return true;};var getLatestBlock = () => blockchain[blockchain.length - 1];var queryChainLengthMsg = () => ({'type': MessageType.QUERY_LATEST});var queryAllMsg = () => ({'type': MessageType.QUERY_ALL});var responseChainMsg = () =>({ 'type': MessageType.RESPONSE_BLOCKCHAIN, 'data': JSON.stringify(blockchain)});var responseLatestMsg = () => ({ 'type': MessageType.RESPONSE_BLOCKCHAIN, 'data': JSON.stringify([getLatestBlock()])});var write = (ws, message) => ws.send(JSON.stringify(message));var broadcast = (message) => sockets.forEach(socket => write(socket, message));connectToPeers(initialPeers);initHttpServer();initP2PServer();

8.

At present, blockchain has developed from 1.0 to 3.0 era: 1.0 is bitcoin, 2.0 is Ethereum, and 3.0 is DAPP era. DAPP is to blockchain just as app is to IOS and Android

DAPP brings us hope for the future blockchain world based on consensus mechanism, smart contract, cross chain integration and other blockchain technologies. In the future, we may need only one DAPP to handle many cooperation and transactions based on "trust" and "value". Because this DAPP already contains most of your important assets, including your personal credit, bank deposits, consumption, friends and so on

This is the original intention of Da dapps

Da dapps is a one-stop application ecological platform of global blockchain developed by equity bank's Bahamas international technology R & D center and relying on Intelligent innovation technology. Da dapps will grasp the trend of the digital era of blockchain, integrate the existing advantages of artificial intelligence, and strive to use innovative technology and blockchain to change the global financial and payment system

Da dapps is a model unit of wdeo of the United Nations. The cooperative organizations are UBS group, United digital central bank of the world, world digital stock exchange, Panamanian Sintai bank, etc. Da dapps integrates decentralized social, payment, wallet, application, cloud storage and other functions to provide users with decentralized ecological services. Da dapps is expected to be the IOS or Android in DAPP application, and become the hot focus of DAPP in the world

with its technical advantages, the project team has provided intelligent technology services for financial consulting, asset management, banking and securities derivatives trading, fund and foreign exchange business in many countries around the world. The project abides by the laws and regulations under the framework of the United Nations digital economy organization, relies on the strong strength of banks and the international top resource advantages of cooperative institutions, and ensures the asset security of global digital currency users from multiple dimensions. In addition, we will make ecological layout all over the world, and strive to build a global top multi business form as one of the blockchain one-stop ecosystem

the project team has been working hard to promote DAPP's ecological sustainable innovation and development, and actively developed various tools to make decentralized applications easy to use, cheap and fast. At the same time, the platform cooperates with DAPP application development teams all over the world to promote new and creative DAPP, so as to change the global DAPP development, service and operation mode

in order to better promote the global expansion plan of Da dapps platform and promote the development of dapps instry, the project party decided to hold a grand Ecological Application Conference in Ha Long Wan, Vietnam from June 29 to July 3, 2019

this press conference adheres to the purpose of "leading the world and linking the future". Discuss the development trend of Da dapps global blockchain ecological application, and jointly witness Da global circulation, convenient payment and global online and offline massive scene applications

according to the development of the mainstream DAPP, the Da dapps platform has been involved in nine categories, such as trading market, guessing, game, finance, social networking, media, storage, assets and governance. Offline application cooperation instries include latex, aloes, gambling, ty-free shops, real estate, etc

9. It's from a Singapore non-profit foundation.

10. It's the Singapore Foundation: grandteam. Dagt foundation is a non-profit organization established in Singapore. As the operation entity of dagt project, the foundation will focus on the development and construction of dagt system and effectively implement the work in accordance with the established objectives.