Voting ethereum

The system works like this: an election admin sends ethereum a 'white list' of voters. Later, when a voter registers for an election, he or she puts down a small deposit. Voters then have a limited time to cast their vote, or lose the deposit. When a vote is cast, it is first encrypted before being submitted to ethereum.

Once all the votes are in or the time limit for voting is up , ethereum computes the tally, keeping votes private. And once the final voter casts a vote, he or she cannot change that vote, even after computing the tally. McCorry explained that his approach rides on the fact that the people in the election are known — an advantage in that it allows the use of peer pressure to encourage voting. Road ahead Moving forward, McCorry foresees a time when decentralized vote collections are implemented widely.

Because it has been in academic literature for years, but it has never been practically implemented," McCorry said. He added that the project — the code for which is now available on Github — also demonstrates that ethereum can support cryptography, as the Open Vote Network uses both ElGamal and zero-knowledge proofs.

In the input field next to the Create button, enter an array of candidate names like ["Rama", "Nick", "Jose"] and click Create. You should see a message in Solidity that the transaction is waiting to be mined. To mine the transaction go to the Geth CLI and type: miner. You have now deployed the Smart Contract.

The deployed contract has an address location on blockchain and an interface, which allows you to interact with it. Copy the interface and the address to a text file. You will need them later. To copy the contract interface go to the Compile tab and click Details. This will open a popup, which will have a copy button for the interface. To copy the contract address click on the copy button next to the contract name. You can now stop mining. Go to the Geth CLI and type: miner.

You are going to interact with your Smart Contract using the Web3 library.

Confirm. ethereum failed transaction sorry, that

Voting: Voters vote for their preferred candidate's name publicly listed in the Blockchain using the function "vote". Election result: Any vote before the start datetime and after end datetime will not be accepted by the Smart Contract. Any vote from an unauthorized Ethereum address will not be accepted by the Smart Contract. Only one vote from each authorized Ethereum address will be accepted by the Smart Contract.

Election result can be audited in real time in the Blockchain. Any vote to an unregistered candidate will not be valid. The whole process from the registrations to the voting and counting the results is open to audition by anyone. Contribution This basic schema can be implemented today with the existing infrastructure. A contract is written in Solidity , a smart contract language, and is a collection of code and data that resides at a specific address on the Ethereum blockchain.

Smart Contracts, along with the Blockchain, are the basis of all Decentralized Applications. They are, like Blockchain, immutable and distributed, which means upgrading them will be a pain if they are already on the Ethereum Network. Fortunately, here are some ways to do that. This API abstracts the communication with Ethereum Clients, allowing developers to focus on the content of their application.

You must have a web3 instance imbedded in your browser to do so. Other Tools we will use Truffle is a popular testing development framework for Ethereum. It includes a development blockchain, compilation and migration scripts to deploy your contract to the Blockchain, contract testing, and so on. It makes development easier! Metamask brings Ethereum to your browser. It is a browser extension that provides a secure web3 instance linked to your Ethereum address, allowing you to use Decentralized Applications.

We will not be using Metamask in this tutorial, but it is a way for people to interact with your DApp in production. Instead, we will inject our own web3 instance during development. For more information, check out this link. For ease of explanation, it will just be a one page application where a user can enter their ID and vote for a candidate. There will also be a button that counts and displays the number of votes per candidate. This way, we will be able to focus the process of creating and interacting with the smart contracts within an application.

The source code for this entire application will be in this repository , and you will need to have Node. Thus, I created this repo the one linked in the instructions above. Build artifacts describe the function and architecture of your contract and give Truffle Contracts and web3 information on how to interact with your Smart Contract in the Blockchain.

Write your Smart Contracts Enough with the setup and introduction. For any application, you want your smart contracts to be as simple as possible, even stupidly simple. So, you really want it to work perfectly——meaning, the more complex it is, the easier it is to make a mistake. Our contract will include: State Variables — variables that hold values that are permanently stored on the Blockchain. We will use state variables to hold a list and number of Voters and Candidates.

Functions — Functions are the executables of smart contracts. They are what we will call to interact with the Blockchain, and they have different levels of visibility, internally and externally. This allows Javascript callback functions or resolved promises to view the certain value you wanted to pass back after a transaction.

This is because every time you make a transaction, a transaction log will be returned. Struct Types — This is very similar to a C struct. Structs allow you to hold multiple variables, and are awesome for things with multiple attributes. Candidates will only have their name and party, but you can definitely add more attributes to them. Mappings — Think of these like hash-maps or dictionaries, where it has a key-value pair. We will use two mappings. These five encompass many of the structures a smart contract will generally use.

These types are explained more in depth here. Note that this file should be called Voting. Basically, we have two Structs types that hold multiple variables that describe a Voter and a Candidate. With Structs, we are able to assign multiple properties to them, such as emails, address, and so on.

To keep track of Voters and Candidates, we put them into separate mappings where they are integer indexed. We also keep track of the number of Voters and Candidates, which will help us index them. I know, contrary to what I said earlier about making contracts super simple, I made this contract a little more complicated in comparison to what this application actually does.

However, I did this so that it would be a lot easier for you guys to make edits and add features to this application afterward more on that at the end. Note that the state variables numCandidates and numVoters are not declared public. We are using 32bytes for strings instead of using the string type. When a user votes, a new Voter struct is created and added to the mapping. In order to count the number of votes a certain candidate has, you must loop through all the Voters and count the number of votes.

Candidates operate on the same behavior. Thus, these mappings will hold the history of all Candidates and Voters. Instantiate web3 and contracts With our Smart Contract completed, we now need to run our test blockchain and deploy this contract onto the Blockchain. To start the development Ethereum blockchain, go to your command line and run: truffle develop This will live on your command line. Since Solidity is a compiled language, we must compile it to bytecode first for the EVM to execute.

Next, we must migrate the contract. Remember that your contract is deployed to a certain address on the Blockchain, so whenever you make changes, your contract will be located at a different address. Migrations help you do this and also help you move data around. Your smart contract is now on the Blockchain forever. Well, not really…. If you are using Ganache, you will not need to call truffle develop.

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A guide to developing an Ethereum decentralized voting application by Timothy Ko A guide to developing an Ethereum decentralized voting application Photo by Andre Francois After the entire cryptocurrency market passed 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. Why make a Decentralized Voting app? 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. Even if the attacker was able to achieve that while incorrectly entering user votes with their real IDs under the radar, end to end voting systems could allow voters to verify whether their vote was correctly entered in the system, making the system extremely safe.

Core Components of Ethereum I do expect you to have an understanding of Blockchain and Ethereum for the remainder of this guide. Smart Contracts act as the back-end logic and storage. A contract is written in Solidity , a smart contract language, and is a collection of code and data that resides at a specific address on the Ethereum blockchain. Smart Contracts, along with the Blockchain, are the basis of all Decentralized Applications.

They are, like Blockchain, immutable and distributed, which means upgrading them will be a pain if they are already on the Ethereum Network. Fortunately, here are some ways to do that. This API abstracts the communication with Ethereum Clients, allowing developers to focus on the content of their application.

You must have a web3 instance imbedded in your browser to do so. Other Tools we will use Truffle is a popular testing development framework for Ethereum. It includes a development blockchain, compilation and migration scripts to deploy your contract to the Blockchain, contract testing, and so on. It makes development easier!

Metamask brings Ethereum to your browser. It is a browser extension that provides a secure web3 instance linked to your Ethereum address, allowing you to use Decentralized Applications. We will not be using Metamask in this tutorial, but it is a way for people to interact with your DApp in production. Instead, we will inject our own web3 instance during development. For more information, check out this link. For ease of explanation, it will just be a one page application where a user can enter their ID and vote for a candidate.

There will also be a button that counts and displays the number of votes per candidate. This way, we will be able to focus the process of creating and interacting with the smart contracts within an application. The source code for this entire application will be in this repository , and you will need to have Node. Thus, I created this repo the one linked in the instructions above. Build artifacts describe the function and architecture of your contract and give Truffle Contracts and web3 information on how to interact with your Smart Contract in the Blockchain.

Write your Smart Contracts Enough with the setup and introduction. For any application, you want your smart contracts to be as simple as possible, even stupidly simple. So, you really want it to work perfectly——meaning, the more complex it is, the easier it is to make a mistake.

Our contract will include: State Variables — variables that hold values that are permanently stored on the Blockchain. We will use state variables to hold a list and number of Voters and Candidates. Functions — Functions are the executables of smart contracts. They are what we will call to interact with the Blockchain, and they have different levels of visibility, internally and externally.

This allows Javascript callback functions or resolved promises to view the certain value you wanted to pass back after a transaction. This is because every time you make a transaction, a transaction log will be returned. Struct Types — This is very similar to a C struct.

Structs allow you to hold multiple variables, and are awesome for things with multiple attributes. Candidates will only have their name and party, but you can definitely add more attributes to them. Mappings — Think of these like hash-maps or dictionaries, where it has a key-value pair. We will use two mappings. These five encompass many of the structures a smart contract will generally use.

These types are explained more in depth here. Note that this file should be called Voting. Basically, we have two Structs types that hold multiple variables that describe a Voter and a Candidate. With Structs, we are able to assign multiple properties to them, such as emails, address, and so on. To keep track of Voters and Candidates, we put them into separate mappings where they are integer indexed. We also keep track of the number of Voters and Candidates, which will help us index them.

I know, contrary to what I said earlier about making contracts super simple, I made this contract a little more complicated in comparison to what this application actually does. The EIP author is responsible for reaching consensus within the community and documenting alternative opinions. Given the high technical barrier for submitting a well-formed EIP, historically, most EIP authors are typically application or protocol developers. Why do EIPs matter? EIPs play a central role in how changes happen and are documented on Ethereum.

They are the way for people to propose, debate and adopt changes. Every network upgrade consists of a set of EIPs that need to be implemented by each Ethereum client on the network.