Proof-of-work is a consensus algorithm underpinning blockchain platforms such as Bitcoin and Ethereum.

For a through explanation of how it works and a wider dive into the nuts and bolts of a blockchain, please check out this link.

In the meantime, this is a simple interface to visualize how it works. Follow the steps below to simulate how it works:

• Enter transactions - i.e. John sends 1 to Mary - and submit. Any transactions entered will be mined in the next block.
• Click on "Mine".

At this point, the algorithm takes an object representing the block to be mined - consisting of:

• A block ID that increments from the previous block
• The cryptographic hash of the previous block.
• The transactions that are pending.

It will then start the process of finding a proof (often referred to as a nonce) to add to this object, such that the hash of this object starts with four zeros. Once this proof is found, the new block is added to the chain. The validity of the proof (once it is available) is easily verifiable.

Having a reference to the previous block ensures that each block is "chained" to the previous one. Imposing a requirement for the cryptographic hash means that it would require considerable computing power to alter a transaction, as one would then need to find a valid hash for all subsequent blocks in order to keep the integrity of the chain.

Install dependencies

cd client
yarn install

Run a build:

yarn build

Start the server:

cd ..
flask run

The interface should now be visible on localhost:5000.

On the server side, the proof-of-work algorithm is written in Python and the server is set up using Flask.

The front end is developed with Vue and Vuetify.

This project was undertaken in my time as a student at Code Chrysalis.