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

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

실행방법

1. Node1 에서 HTTP_PORT=3001 P2P_PORT=6001 npm start

2. Node2 에서 HTTP_PORT=3002 P2P_PORT=6002 npm start

3. Node 1이나 2에서 addPeer 명령어 보내기

Parameter :
{
	"peer" : "ws://localhost:6002"
}

4. newTransaction 명령어로 트랜잭션 발생

Parameter :
{
	"sender" : "0",
	"receiver" : "1",
	"value" : "1",
	"in_counter" : "0",
	"out_counter" : "0",
	"transactionHash" : "0",
	"inputs" : "0",
	"outputs" : "0"

}

5. transactions 명령어로 memory pool확인

6. Blocks 명령어로 블록체인확인

7. mineBlock 명령어로 블록 채굴

Parameter :
{
	"data": "localhost:3001"
}

(임의로 설정했음)