A simple blockchain made in python.

This repository is a barebones implementation of a blockchain. It uses the proof of work protocol (sha256 with 4 leading zeros by default), and uses the 'longest is authoritative' consensus algorithm.

git clone https://github.com/kasperfred/blockchain.git
cd blockchain

The blockchain relies on requests and Flask.

This implementation offers a simple webapi for handling nodes.

To start a node, run the following command.

python3 app.py

This exposes a webapi you can use to communicate with the node.

GET: http://0.0.0.0:5000/

3f99f012-3620-494b-934b-261b6958c511

This will will add other nodes to the network.

POST: http://0.0.0.0:5000/nodes/register
BODY (JSON): {"nodes":["192.168.1.124:5000", "192.168.1.125:5000"]}

The body should be a JSON object with a nodes key containing a list of reachable addresses belonging to other nodes on the network.

Runs consensus algorithm (longest chain is authoritative)

GET: http://0.0.0.0:5000/nodes/resolve

Get the chain of the node.

GET: http://0.0.0.0:5000/chain

This will add a transaction to a future block.

POST: http://0.0.0.0:5000/transactions/new
BODY (JSON): {"whatever":"your transaction looks like"}

Transaction will be added to Block {block_index}

This will mine a block using the proof of work protocol.

GET: http://0.0.0.0:5000/mine