Developing a Decentralized Voting Application on Azure

Welcome to this hands-on lab where we will explore the fascinating intersection of blockchain technology and cloud computing, focusing on Microsoft’s Azure platform. As the demand for secure, transparent, and efficient systems continues to grow, decentralized technologies such as blockchain have stepped into the limelight. This lab is designed to give you practical experience in creating a decentralized voting application, providing a unique blend of cryptographic security measures offered by blockchain and the powerful computing resources available on Azure.

Why decentralized voting? Traditional voting systems, although generally reliable, are often subject to scrutiny regarding their transparency, security, and the possibility of fraud. Decentralized voting applications aim to mitigate these concerns by creating an immutable and transparent record of votes, accessible to anyone who wishes to verify the results, yet...

Technical requirements

To run the code and scripts presented in this chapter, you will need an account in the Azure cloud. A free account, which you can obtain at https://azure.microsoft.com/en-us/free/, will suffice.

All the source code is available in this book’s GitHub repository: https://github.com/PacktPublishing/Developing-Blockchain-Solutions-in-the-Cloud.

Introduction to developing a decentralized voting application on Azure

Ensuring data integrity, voter privacy, and system robustness is essential for any voting application, particularly in a decentralized environment. Before we cover the implementation details of the proposed solution, I would like to illustrate a few common cryptographic techniques that can be used to improve data integrity, voter privacy, and overall system robustness. We can then implement some or all of these techniques in the smart contract of the voting application:

Figure 14.1 – Cryptographic techniques in a decentralized application

Data integrity

A very common approach to ensure data integrity in a decentralized application is to digitally sign and verify a transaction. Digital signatures are based on asymmetric encryption algorithms and the use of private and public keys.

In our voting app, every vote can be digitally signed using the voter’s private key...

Setting up the blockchain network on Azure

Now, let’s progress with setting up the cloud infrastructure for the voting application, which includes a blockchain consortium on Azure and the relevant voting smart contract. The scripts in this section will leverage the Azure Command-Line Interface (CLI) for execution. We will deploy the smart contract with Truffle, and we will also need MetaMask or a similar Ethereum wallet to sign the voting transactions.

Creating a blockchain consortium on Azure

We will create a blockchain consortium through the Azure portal using bash instructions in the Azure CLI to set up an Ethereum network. Here is an example using the Azure CLI:

rg_name="MyResourceGroup"
location="eastus"
consortium_name="MyBlockchainConsortium"

First of all, we must set some global variables to indicate the following:

• The resource group where we will save all the deployed resources (the rg_name variable).
• The Azure region...

Developing the voting application frontend

After deploying the contract into the blockchain network, we need a frontend user interface for interacting with the voting application. The frontend code will then communicate with the smart contract and perform voting operations.

We will now create a Blazor UI frontend to interact with the Solidity smart contract. As Blazor runs on .NET, this example will use the Nethereum library, which is a .NET library for integrating Ethereum smart contracts using C# code.

Installing the necessary packages

First, let’s make sure we add the Nethereum.Web3 package to our Blazor project, either from the NuGet package manager in Visual Studio, as illustrated in the following screenshot, or by running a command-line instruction to install the package:

Figure 14.3 – The Nethereum.Web3 NuGet package

The bash command to add the Nethereum.Web3 package to our .NET solution is as follows:

dotnet add package...

Summary

This hands-on lab offered a comprehensive guide to building a decentralized voting application while utilizing Azure services for running a blockchain network and hosting a .NET Blazor frontend. The primary goal was to educate participants on how to create a robust, scalable, and secure voting platform that can be transparently audited and managed.

We learned about two key capabilities from this lab. The first one is related to the use of a smart contract for the voting logic, whereas the second one is related to the Blazor frontend and communication with the smart contract.

More specifically, we learned how to write, deploy, and interact with an Ethereum smart contract that handles the voting logic while using the Solidity programming language and the Nethereum library for .NET. We also developed a user interface in Blazor that interacts with the Ethereum smart contract, enabling users to cast votes, view candidates, and see real-time results.

In the next chapter...

Further reading

• Get started with Azure: https://azure.microsoft.com/en-us/get-started
• Blazor: https://dotnet.microsoft.com/en-us/apps/aspnet/web-apps/blazor
• Nethereum: https://nethereum.com/