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Ethereum Voting Tutorial

A Guide To Developing An Ethereum Decentralized Voting Application

A Guide To Developing An Ethereum Decentralized Voting Application

A guide to developing an Ethereum decentralized voting application After the entire cryptocurrency market passed 700 billion dollars in market cap, the cryptocurrency space exploded over these last couple months. But this is just the beginning. As blockchain systems continue to evolve and scale, one great way to dip into this new space and leverage this technology is with decentralized applications, otherwise known as dApps. CryptoKitties , famous for its congestion of the Ethereum Blockchain, is a great example of a dApp, uniquely combining concepts of breedable and collectible cats with the blockchain. This sensational game is just one creative example out of a virtually unlimited number of opportunities. Although seemingly very complicated, certain frameworks and tools have been developed to abstract your interactions with the blockchain and smart contracts. In this blog post, I will go over one way to create a decentralized voting app on Ethereum. I will briefly go over Ethereum, but you probably should have an understanding of it to use this guide to the fullest. In addition, I do expect you to know Javascript. Essentially, a great decentralized application utilizing blockchain technology allows you perform the same actions you would today (like transferring money) without a trusted third party. The best dApps have a specific real world use-case that leverages the unique characteristics of blockchain. In essence, the blockchain is a shared, programmable, cryptographically secure and therefore trusted ledger which no single user controls and which can be inspected by anyone.- KlausSchwab Even though a voting app might not be a great app for consumers, Ive chosen to use it for this guide because the main issues blockchain solves transparency, security, accessibility Continue reading >>

Learn Solidity: Complete Example: Voting Ballot Smart Contract

Learn Solidity: Complete Example: Voting Ballot Smart Contract

Learn Solidity: Complete Example: Voting Ballot Smart Contract Learn Solidity: Complete Example: Voting Ballot Smart Contract In this post, we willgo through the complete example of a Voting Ballot smart contract. This is a fully working smart contract for voting . Notice: This is one of the multi-post series of Learn Solidity - Build Decentralized Application in Ethereum . This is an attempt to teach you all about Solidity - A Programming Language for Ethereum Based Smart Contracts . If you want to take this as a video course please signup using below button. pragma solidity ^0.4.9;/// @title Voting with delegation.contract Ballot { // This declares a new complex type which will // be used for variables later. // It will represent a single voter. struct Voter { uint weight; // weight is accumulated by delegation bool voted; // if true, that person already voted address delegate; // person delegated to uint vote; // index of the voted proposal } // This is a type for a single proposal. struct Proposal { bytes32 name; // short name (up to 32 bytes) uint voteCount; // number of accumulated votes } address public chairperson; // This declares a state variable that // stores a `Voter` struct for each possible address. mapping(address => Voter) public voters; // A dynamically-sized array of `Proposal` structs. Proposal[] public proposals; /// Create a new ballot to choose one of `proposalNames`. function Ballot (bytes32[] proposalNames) { chairperson = msg.sender; voters[chairperson].weight = 1; // For each of the provided proposal names, // create a new proposal object and add it // to the end of the array. for (uint i = 0; i < proposalNames.length; i++) { // `Proposal({...})` creates a temporary // Proposal object and `proposals.push(...)` // appends it to the end of `pro Continue reading >>

Bit-z Voting Tutorial

Bit-z Voting Tutorial

Heres what you need before you begin the process: Please make sure you have a valid form of ID, it can be: 1. drivers license 2. ID card or 3. passport. Scan the ID with no less than 1000K and clearly visible, in jpg, jpeg, or png format. If you have all this the process shouldnt take more than 5 minutes, ready? Write your emailaddress, a password of your choice, and ID number (drivers license, ID card or passport) and complete the verification code. Please press Submit. Go to your email and open an email called Please activate your account and click on the link. Before turning on 2FA, write down or print a copy of your 16-digit key andput it in a safe place.After that complete the two-Factory Authentication(2FA) process with yourLogin Password. Before you write your email address, click Get Verification Code. Check you email and get your2FA Code.Or scan to obtain the barcode with the Google Authentication app on your phone. Once you get in your account click on the top left button Vote. Please choose Jesus Coin from the list of coins numbered. Now push the blue letters that say Please complete level 3 verificationon the top right of the page. C- Create and confirm a password that is different from your login password A- Enter your social security or passport numbers B- Enter a scanne piece of ID with no less than 1000K and clearly visible, in jpg, jpeg, or png format C- Enter a picture of you holding your passport or ID card with your hands, and the picture must include a white paper writing Bit-Z and the current date. Your face must be clearly visible with equally clear ID details, failing to do so will have a negative impact on your approval progress Vote for Jesus Coin and receive your reward! Jesus Coins are built on the Ethereum Network. For this reason, you need Continue reading >>

Tutorial For Building An Ethereum Dapp With Integrated Web3 Monitoring

Tutorial For Building An Ethereum Dapp With Integrated Web3 Monitoring

Tutorial for building an Ethereum DApp with Integrated Web3 Monitoring Tutorial on building an Ethereum decentralized app with Solidity and Truffle, and integrating Moesif API Insights for monitoring Web3 interactions. Co-founder @Moesif @TroveMarket, Worked @Zynga @Microsoft, Studied @MIT, Invested @HornetApp @ECitySky This post walks through the steps to creating a simple Ethereum DApp usingWeb3.js and Truffle and set up monitoring of the API transactions sent tothe blockchain. This article also provides explanation of various pieces of technologyinvolved in developing DApps. Decentralized Applications (or DApps) are applications that do not rely on a centralized backendrunning in AWS or Azure that power traditional web and mobile applications(outside of hosting the frontend code itself). Instead,the application interacts directly with a blockchain which can be thought of distributedcluster of nodes analogous to applications interacting directly with a masterlesscluster of Cassandra nodes with full replication on every peer in anuntrusted peer-to-peer network. These blockchain nodes do not require a leader which would defeat the purpose ofbeing truly decentralized. Unlike leader election in various consensus protocols like Raft and Paxos ,blockchain transactions are sent to and processed by random nodes via Proof of Work or Proof of Stake.These nodes are untrusted nodes running in an arbitrary sized network onvarious compute devices around the world. Such technology can enable true decentralized ledgers and systems of records. DApps are the frontend apps which interact with these blockchain over an API. For Ethereum , this API is a JSON-RPC layer called the Ethereum Web3 API which Moesif supports natively. Ethereum is an implementationof blockchain technology that ca Continue reading >>

Full Stack Hello World Voting Ethereum Dapp Tutorial

Full Stack Hello World Voting Ethereum Dapp Tutorial

Full Stack Hello World Voting Ethereum Dapp Tutorial This post will chronicle my attempts to follow the instructions of an article by Mahesh Murthy that does what the title suggests: implement an Ethereum-based voting app. As of now, it seems like most development will take place in the command line. Ive downloaded a Solidity extension for Visual Studio, but I feel the relative newness of Ethereum/Solidity/Blockchain means that it will be sometime before the IDE will be as mature as say C# development is in Visual Studio. The latest tools and methods will typically start at the command line, so thats where I will start. NB: remember to open command line with admin privileges. Had to restart an installation because of insufficient write privilege. Above is the setup of a fake blockchain environment for running the voting dapp on. And this is the fake ethereum host, ready & waiting for contracts (I believe!) Next, open another console to act as compiler and client, and enter node to open node console. The second circle shows as api connection to the given port number of the server, as seen in the circle of the above picture. NOTE: Forgot to post or keep this updated whilst I continued, so posting this unfinished version now, may update with further results. The main result was: Wow, this is pretty complicated. Looks like I cant just pick up Solidity and blockchain away, Im gonna have to learn AngularJS a derivation of Javascript, which thankfully I have some experience with but still will need more time than Im afforded right now. Continue reading >>

Zastrin | Learn Ethereum Programming By Doing Real-world Projects

Zastrin | Learn Ethereum Programming By Doing Real-world Projects

We are excited to introduce our new Referral program! If you liked our courses, please share this coupon code with your friends. For every friend who buys a course using your code, they receive 25% off and you will be credited 25% of the course price in to your account that you can use for future purchases. Zastrin teaches you Ethereum blockchain programming through real-world projects. Our courses will help you learn the core concepts and introduces you to the key libraries and frameworks required to build production quality dapps. Our step-by-step guides help you build projects from the ground up. Overview of a generic blockchain, concepts and workings of the Ethereum blockchain and languages and frameworks required to build decentralized applications. Decentralized application development is unlike web/mobile development. There are many moving parts and you have to carefully consider various issues such as security, time/space complexity and so on. Our courses help you think and architect successful decentralized applications. Truffle is a dapp development framework that is used to make application development easy. It abstracts away many complexities of the Ethereum blockchain development and helps accelerate development. Our Dapps will be built using the Solidity programming language using the Truffle framework. The goal of these courses is to help you understand the concepts of the Ethereum blockchain and build real-world decentralized applications. By the end of this series of courses, you'll be able to build your own decentralized applications. This is a beginner course ideal for any one with very basic or no knowledge of the Ethereum blockchain. In this course, you will build a simple Decentralized Voting application. In this course, you will build a Dapp whic Continue reading >>

Designing The Architecture For Your Ethereum Application

Designing The Architecture For Your Ethereum Application

Developer and Security Researcher at Zeppelin Solutions. Designing the architecture for your Ethereum application As you are beginning with Ethereum development, and after going through some of the many excellent tutorial posts out there, you are faced with the challenge of building your first Ethereum-based app. This brings up a set of new challenges around designing the architecture and layout of your application: traditional client-server applications now have a third new component in the mix, the blockchain. In this article Ill cover some of the most traditional scenarios for Ethereum applications, which arise from the different interactions between these three components. Ill discuss serverless apps, browser plugins, private nodes, offline signing, and other issues that play a role when designing the layout of your solutions. The canonical flavour of an Ethereum app is a serverless one, where the entire flow of your app happens entirely between the client and the blockchain. The first step here is to actually distribute the client code to your users. The easiest way is to set up a static page that contains a web3-enabled web app. Such page can be hosted anywhere: AWS S3 , Google Cloud , Github pages , other cloud providers, or your own server. Furthermore, if you can count on your clients having either bzz or ipfs protocol support, you can even disitribute it via Swarm or IPFS for total decentralization. Next step is for the app to be able to read information from the blockchain, which, as you already know, requires a connection to an active Ethereum node. This will be set by your web3 provider , which is the piece that handles the actual web3 connection to a node. Now, some of your users may already have an established connection to a node, for instance, via the Continue reading >>

Build Your First Ethereum Smart Contract With Soliditytutorial

Build Your First Ethereum Smart Contract With Soliditytutorial

Finance & Tech Nerd, Investor, Blockchain & Crypto Enthusiast, Wannabe Polymath, Master of Discipline in Training, Laissez Faire. Talk Is Cheap. Build Your First Ethereum Smart Contract with Solidity Tutorial So you wanna build a smart contract? Perhaps you want to understand how they work, maybe you want to build your own Dapp, maybe you want to launch the very first billion dollar ICO (sarcasm)... Regardless of your intentions, learning how smart contracts work is invaluable. The Ethereum platform possesses enormous potential to create Dapps that could change the way we interact on the web in the decades to come. While Ethereum deploys smart contracts that work much like a standard blockchain transaction, they yield a conditional statement that must be met before a function(s) is executed. Smart contracts can be used for voting, crowdfunding, blind auctions, multi-signature wallets and MUCH more. Bob has his own scrap metal depot business in the United States, Eric is his iron scrap supplier. Eric is based out of China. Bob and Eric have a GREAT business relationship. They trust each other and have been doing business for a long time. Both have booming businesses, and Bob in particular sells out of iron scrap on a routine basis. Bob deploys a contract where once his iron scrap inventory reaches a certain range, he automatically sends an order out to Eric for X lbs of iron scrap at Y ether per ton. Eric agrees to the arrangement and accepts Bobs payment in ether right away. Eric gets to work right away and starts fulfilling Bobs order. Eric can exchange his ether at a local exchange online for Yuan for a tiny fee and itll be processed instantaneously. Whether Eric decides to hold ether or convert to Yuan is his choice, but either way he can now put this capital to wor Continue reading >>

Full Stack Hello World Voting Ethereum Dapp Tutorialpart1

Full Stack Hello World Voting Ethereum Dapp Tutorialpart1

Techie, Foodie, Traveler, Tinkering with Blockchain at www.zastrin.com Full Stack Hello World Voting Ethereum Dapp Tutorial Part1 In my previous post , I explained the high level architecture of Ethereum platform comparing it to a web application. As a developer, the best way to learn any new technology is by diving in and building toy applications. In this post, lets build a simple Hello World! application which is a Voting application. The application is extremely simple, all it does is initialize a set of contestants, let anyone vote for the candidates and display the total votes received by each candidate. The goal is not to just code an application but to learn the process of compiling, deploying and interacting with it. I have deliberately avoided using any dapp frameworks to build this application because the frameworks abstract away lot of the details and you fail to understand the internals of the system. Also, when you do use a framework, you will have more appreciation for all the heavy lifting the framework does for you! In lot of ways, this article is a continuation of the previous post . If you are new to the world of Ethereum, I recommend reading it before continuing. Learn the process of writing a contract, compiling it and deploying it in your development environment. Interact with the contract on the blockchain through a nodejs console. Interact with the contract through a simple web page to display the vote counts and vote for candidates through the page. The entire application set up and build was done on a fresh installation of ubuntu 16.04 xenial. I have set up and tested the application on macos as well. This is how I would visualize this application we are going to build. 1. Setting up the development environment Instead of developing the app ag Continue reading >>

Full Stack Hello World Voting Ethereum Dapp Tutorialpart2

Full Stack Hello World Voting Ethereum Dapp Tutorialpart2

Full Stack Hello World Voting Ethereum Dapp Tutorial Part2 [Tutorial was last updated in January 2018] In part 1 of this tutorial, we built a simple voting application in our development environment using ganache. Now, lets get this application on the real blockchain. Ethereum has a few public test blockchains and one main blockchain. Testnet: There are a few test blockchains such as Ropsten, Rinkeby, Kovan. Think of these as a QA or a staging server, they are used for testing purposes only. All the Ether you use on these networks is fake. Mainnet (also called Homestead): This is the blockchain which the entire world transacts on for real. There is real value to the Ether you use on this network. In this tutorial, we will accomplish the following: Install geth the client software used to download the blockchain and run the Ethereum node on your local machine. Install the Ethereum dapp framework called Truffle which will be used for compiling and deploying our contract. Make small updates to our Voting application to make it work using truffle. Compile and deploy the contract to the Rinkeby testnet. Interact with the contract through truffle console and then through a webpage. I have installed and tested everything on MacOS and Ubuntu. Installation is pretty straightforward: [email protected]:~$ sudo apt-get install software-properties-common [email protected]:~$ sudo add-apt-repository -y ppa:ethereum/ethereum [email protected]:~$ sudo apt-get update [email protected]:~$ sudo apt-get install ethereum You can find installation instructions for various platforms here: Once you have installed geth, run the below command in your command line console: [email protected]:~$ geth --rinkeby --syncmode "fast" --rpc --rpcapi db,eth,net,web3,pers Continue reading >>

Create A Democracy Contract In Ethereum

Create A Democracy Contract In Ethereum

"On the Blockchain, no one knows you're a fridge" So far, all contracts we listed were owned and executed by other accounts probably held by humans. But there is no discrimination against robots or humans in the Ethereum ecosystem and contracts can create arbitrary actions like any other account would. Contracts can own tokens, participate in crowdsales, and even be voting members of other contracts. In this section we are going to build a decentralized and democratic organization that exists solely on the blockchain, but that can do anything that a simple account would be able to. The organization has a central manager that decides who are the members and the voting rules, but as we'll see, this can also be changed. The way this particular democracy works is that it has an Owner which works like an administrator, CEO or a President. The Owner can add (or remove) voting members to the organization. Any member can make a proposal, which is in the form of an ethereum transaction to either send ether or execute some contract, and other members can vote in support or against the proposal. Once a predetermined amount of time and a certain number of members has voted, the proposal can be executed: the contract counts the votes and if there are enough votes it will execute the given transaction. pragma solidity ^0.4.16;contract owned { address public owner; function owned() public { owner = msg.sender; } modifier onlyOwner { require(msg.sender == owner); _; } function transferOwnership(address newOwner) onlyOwner public { owner = newOwner; }}contract tokenRecipient { event receivedEther(address sender, uint amount); event receivedTokens(address _from, uint256 _value, address _token, bytes _extraData); function receiveApproval(address _from, uint256 _value, address _token, byt Continue reading >>

Part 2: Ethereum Testnets

Part 2: Ethereum Testnets

In contrast to bitcoin, Ethereum lets you publish all kinds of contracts that do not have to be related to cryptocurrency at all. You could, for example, write a voting app where you give users the possibility to vote for a certain candidate. You find that idea acting as the basis for this tutorial: Full Stack Hello World Voting Ethereum Dapp Tutorial .It is easy to follow the tutorial and it starts to give you a feeling for writing contracts. Moreover, it introduces a developing framework and different ways to connect to a testnet. Now that we are talking about it, the amount of possible ethereum testnets were a bit confusing to me in the beginning. That's why I want to give an overview of those before I advice you to go on with the tutorials. Testing your application on the testrpc testnet is one of the fastest and easiest ways to test the functionality of your smart contracts. Testrpc simulates an Ethereum client and is based on node.js. This network is only meant for testing and development purposes and it comes with ready-made accounts that you can use. I would recommend to use this testnet in the beginning. Then we have the official Ethereum test networks. Those are very similar to the Ethereum network with the only exception that the ether used in those networks does not have any buying power. But it is perfect to test your contracts. However, just as in the ethereum network you need to pay gas (network fee) to the miners in order to perform actions on the network such as transactions. But don't worry, you do not have to buy it! It is indeed quite simple to get free ether for testing purposes in these testnets, just follow the instructions on the testnet website (e.g. for Rinkeby ) and you will have some test ether on your account in no time. You can find a very Continue reading >>

Ethereum Pet Shop -- Your First Dapp | Truffle Suite

Ethereum Pet Shop -- Your First Dapp | Truffle Suite

This series of tutorials will take you through building your first dappan adoption tracking system for a pet shop! This tutorial is meant for those with a basic knowledge of Ethereum and smart contracts, who have some knowledge of HTML and JavaScript, but who are new to dapps. Note: For Ethereum basics, please read the Truffle Ethereum Overview tutorial before proceeding. Creating a Truffle project using a Truffle Box Compiling and migrating the smart contract Creating a user interface to interact with the smart contract Pete Scandlon of Pete's Pet Shop is interested in using Ethereum as an efficient way to handle their pet adoptions. The store has space for 16 pets at a given time, and they already have a database of pets. As an initial proof of concept, Pete wants to see a dapp which associates an Ethereum address with a pet to be adopted. The website structure and styling will be supplied. Our job is to write the smart contract and front-end logic for its usage. There are a few technical requirements before we start. Please install the following: Once we have those installed, we only need one command to install Truffle: To verify that Truffle is installed properly, type truffle version on a terminal. If you see an error, make sure that your npm modules are added to your path. Creating a Truffle project using a Truffle Box Truffle initializes in the current directory, so first create a directory in your development folder of choice and then moving inside it. mkdir pet-shop-tutorialcd pet-shop-tutorial We've created a special Truffle Box just for this tutorial called pet-shop, which includes the basic project structure as well as code for the user interface. Use the truffle unbox command to unpack this Truffle Box. Note: Truffle can be initialized a few different ways Continue reading >>

Build Your First Blockchain Application In 5 Quicksteps

Build Your First Blockchain Application In 5 Quicksteps

Build Your First Blockchain Application in 5 QuickSteps Click here to share this article on LinkedIn To say there is hype around blockchain is an understatement. But in order for this revolution to keep advancing, we need more engineers! Recently, it was announced that there are 14 job openings for every one blockchain engineer. Its clear that theres a talent scarcity and the goal of this tutorial is to provide a blockchain foundation where you can quickly build your first full-stack decentralized application (DApp). We will be building a DApp that works as a voting system and the code can be found here . This tutorial will go over creating, compiling, and deploying the contract on a local blockchain network. You will then have the ability to interact with the contract via a nodejs cosole or a webpage GUI. Keep in mind that this can be completed with limited technical knowledge but it was designed for those that have a little coding experience. As we go through the steps, there will be a brief background on the process meant to serve as a high level overview. If any particular areas catch your interest, dont hesitate to Google around for more information. This is a lightweight approach that allows you to hit the ground running with a full stack project. This tutorial features no frameworks, limited dependencies, and no BS. Step 1: Clone repository and install dependencies # The tutorial was created with the below versions Ganache is a blockchain simulator that runs in memory locally. We will be using this as the test Ethereum blockchain for our app: Solidity code must be compiled. We will use solc to compile our solidity code: We will compile the contract from within the nodejs console: > web3 = new Web3(new Web3.providers.HttpProvider("We can ensure that the web3 obje Continue reading >>

Full Stack Hello World Voting Ethereum Dapp Tutorialpart3

Full Stack Hello World Voting Ethereum Dapp Tutorialpart3

Techie, Foodie, Traveler, Tinkering with Blockchain at www.zastrin.com Full Stack Hello World Voting Ethereum Dapp Tutorial Part3 In Part 1 , we built a simple voting dapp and got it working on our local machine. In Part 2 , we moved our app to use truffle framework and deployed it to the public Ropsten testnet and interacted with it through the truffle console and through a webpage. In this tutorial, we will add few more features to our voting dapp in order to learn a few key concepts. Here is what you will learn in this tutorial: Learn to use new data types like struct to organize and store data on the blockchain. Learn the concept of tokens and its usage. Learn to make payments using Ether, the currency of the Ethereum blockchain platform. You can find all the code in chapter3 directory in this repository: As you may know, in a general election, every citizen gets to cast one vote for their favorite candidate. However there are elections like electing a board of directors of a company where you are a shareholder, you get to vote based on the number of shares you own in that company. So, the more shares you own, the more votes you get. Lets enhance our voting dapp to support this type of election. We will add functionality for anyone to purchase shares in the company. They can then use those shares to vote for the candidates. We will also add a feature to lookup voter information. In the Ethereum blockchain world, these shares are more commonly referred to as tokens. We will refer to these shares as tokens in the rest of this tutorial. If you want to skip all the explanation and want to just see the contract file, you can find it here: . The first step is to declare the variables we need to store all the information we are interested in. Below are the contract variab Continue reading >>

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