# 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](https://en.wikipedia.org/wiki/Blockchain_(database)) : 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](https://medium.com/@lhartikk/a-blockchain-in-200-lines-of-code-963cc1cc0e54#.dttbm9afr5) 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](https://lhartikk.github.io/). 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) ### ```sh 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 ``` # testing