https://github.com/kigawas/minichain

Mini blockchain in Python
https://github.com/kigawas/minichain

bitcoin blockchain cryptocurrency ethereum python3

Last synced: 19 days ago
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Mini blockchain in Python

• Host: GitHub
• URL: https://github.com/kigawas/minichain
• Owner: kigawas
• License: mit
• Created: 2018-04-27T12:04:23.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2023-03-07T20:58:55.000Z (over 1 year ago)
• Last Synced: 2024-10-18T15:08:01.421Z (29 days ago)
• Topics: bitcoin, blockchain, cryptocurrency, ethereum, python3
• Language: Python
• Homepage: https://kigawas.me/minichain/
• Size: 384 KB
• Stars: 12
• Watchers: 2
• Forks: 5
• Open Issues: 3
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# minichain

[![License](https://img.shields.io/github/license/kigawas/minichain.svg)](https://github.com/kigawas/minichain)

[![CI](https://img.shields.io/github/workflow/status/kigawas/minichain/Build)](https://github.com/kigawas/minichain/actions)

[![Codecov](https://img.shields.io/codecov/c/github/kigawas/minichain.svg)](https://codecov.io/gh/kigawas/minichain)

- Using the freshest Python 3 syntax

- UTXO model

- Nakamoto consensus, or PoW

- P2P part is powered by `asyncio` and [`kademlia`](https://github.com/bmuller/kademlia)

- Elliptic curve part is powered by [`coincurve`](https://github.com/ofek/coincurve)

## How to run

Install dependencies first by running `poetry install`.

Open 3 terminals and run separately:

```bash

python -m chain 8999 --mine --debug # block time is around 5s

python -m chain 9000 -b 127.0.0.1 8999 --debug  # no mining

python -m chain 9001 -b 127.0.0.1 9000 --debug --mine  # connecting second node

```

## How to implement

### Find peers

This repo is leveraging [Kademlia algorithm](https://github.com/bmuller/kademlia) for finding peers via UDP and syncing blockchain via TCP.

You can create a UDP server and a TCP server listening at the **same port** to simplify the logic. When it's found peers by Kademlia, our node just directly connects to that IP and port to start syncing blockchain data.

### Sync blocks

A simple example about syncing the latest block:

1. Sending `REQUEST_LATEST_BLOCK` message to a peer or peers.

2. When receiving `REQUEST_LATEST_BLOCK`, send back the message `RECEIVE_LATEST_BLOCK` with block data.

3. When receiving `RECEIVE_LATEST_BLOCK`:

   1. Check the received block is valid or not;

   2. If valid, add it to our blockchain and broadcast it to peers;

   3. Else, check if the block is ahead;

      1. If ahead, sending `REQUEST_BLOCKCHAIN` to peers and wait for the incoming blockchain data.

      2. Else, which means our blockchain is the freshest, do nothing.

For more details, check the [`p2p.py`](https://github.com/kigawas/minichain/blob/master/chain/p2p.py) code. The logic is simple, but more powerful protocols (like log replication of Raft protocol) are based on the simple ideas behind the implementation here.

## Reference

Go check [this](https://blockchaindemo.io/) and [this](https://coindemo.io/) to learn the basics and stay tuned with this repo!