Naivechain - a blockchain implementation in 200 lines of code

Motivation

All the current implementations of blockchains are tightly coupled with the larger context and problems they (e.g. Bitcoin or Ethereum) are trying to solve. This makes understanding blockchains a necessarily harder task, than it must be. Especially source-code-wisely. This project is an attempt to provide as concise and simple implementation of a blockchain as possible.

What is blockchain

From Wikipedia : Blockchain is a distributed database that maintains a continuously-growing list of records called blocks secured from tampering and revision.

Key concepts of Naivechain

Check also this blog post for a more detailed overview of the key concepts

HTTP interface to control the node
Use Websockets to communicate with other nodes (P2P)
Super simple “protocols” in P2P communication
Data is not persisted in nodes
No proof-of-work or proof-of-stake: a block can be added to the blockchain without competition

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Naivecoin

For a more extensive tutorial about blockchains, you can check the project Naivecoin. It is based on Naivechain and implements for instance Proof-of-work, transactions and wallets.

Quick start

(set up two connected nodes and mine 1 block)

npm install
HTTP_PORT=3001 P2P_PORT=6001 npm start
HTTP_PORT=3002 P2P_PORT=6002 PEERS=ws://localhost:6001 npm start
curl -H "Content-type:application/json" --data '{"data" : "Some data to the first block"}' http://localhost:3001/mineBlock

Quick start with Docker

(set up three connected nodes and mine a block)

docker-compose up
curl -H "Content-type:application/json" --data '{"data" : "Some data to the first block"}' http://localhost:3001/mineBlock

HTTP API

Get blockchain

curl http://localhost:3001/blocks

Create block

curl -H "Content-type:application/json" --data '{"data" : "Some data to the first block"}' http://localhost:3001/mineBlock

Add peer

curl -H "Content-type:application/json" --data '{"peer" : "ws://localhost:6001"}' http://localhost:3001/addPeer

Query connected peers

curl http://localhost:3001/peers