Blockchain Demo

This application is a simple implementation of a blockchain using the React JavaScript library and the SHA256 cryptographic hash function from the crypto-js library. It includes a Block class that defines a block and a Blockchain class that defines a blockchain.

The Block class has a constructor function that initializes the properties of the block, including the data, previous hash, timestamp, nonce, and hash. It also includes a calculateHash function that calculates the hash of the block and a mineBlock function that mines the block by repeatedly calculating the block's hash until it meets the difficulty requirement. The Blockchain class has a constructor function that initializes the chain property with an array containing the genesis block. It also includes a createGenesisBlock function that creates and returns the genesis block and a getLatestBlock function that returns the latest block in the chain.

The DIFFICULTY variable is set to 2 and the computeHash, generateRandomPhrase, startTimer and endTimer are helper functions.

The code also includes a console.log statements for debugging and understanding the flow of the code.

This is a simple implementation that can be used as a starting point to understand the basic mechanics of a blockchain.

Classes

Blockchain

The Blockchain class represents a blockchain, which is a chain of blocks that contain data. It has the following methods:

• createGenesisBlock creates and returns the first block in the blockchain, known as the genesis block.
• getLatestBlock returns the latest block in the chain.
• addBlock adds a new block to the chain by setting the new block's previous hash to the hash of the latest block, mining the new block, and adding it to the chain.
• calculateNonce calculates the nonce value of a block by repeatedly recalculating the block's hash until it meets the required difficulty level (determined by the DIFFICULTY constant).
• verifyNonce verifies the nonce of a block by comparing it to the nonce value calculated using calculateNonce.

Block

The Block class represents a block, which consists of data and a hash. A block's hash is calculated using the SHA-256 cryptographic hash function and is based on the block's data, previous block's hash, timestamp, and nonce. It has the following methods:

• calculateHash calculates and returns the hash of the block.
• mineBlock mines the block by repeatedly recalculating the block's hash until it meets the required difficulty level (determined by the difficulty argument).

Components

App

The App component is a React component that displays the blocks in the blockchain and allows the user to add new blocks to the chain or verify the nonce of a block. The user can input data for a new block in a text field, and when the user clicks the "Add block" button, the addBlock

Running the App

To run the app, you will need to have Node.js and npm installed on your machine.

Clone the repository or download the source code. Navigate to the project directory in a terminal. Run npm install to install the required dependencies. Run npm start to start the development server. The app will be available at http://localhost:3000/. Note that this app is a client-side application and does not require a backend server to function. However, it does use the SHA-256 cryptographic hash function, which is provided by the crypto-js library.