Simple Go Blockchain Implementation

Introduction

This project implements a fully functional blockchain system in Go. It provides the structures and functions for creating, managing, and interacting with a blockchain, including a Proof of Work consensus mechanism, Merkle Tree for efficient transaction verification, and a Wallet system for managing user identities and transactions.

Features

• Complete blockchain structure with blocks and transactions
• Proof-of-Work consensus mechanism
• Merkle Tree implementation for efficient transaction verification
• Wallet system for managing user identities and transactions
• Multi-wallet management system
• Transaction creation, signing, and verification
• UTXO (Unspent Transaction Output) model
• Persistent storage using BadgerDB
• Support for multiple nodes (with unique IDs)
• Genesis block creation
• Block mining
• Transaction and block serialization/deserialization
• Wallet persistence and recovery

Installation

$ git clone https://github.com/mapfumo/golang-blockchain.git
$ cd golang-blockchain
$ go build -o blockchain-cli main.go

Usage

$ ./blockchain-cli
Usage:
 getbalance -address ADDRESS - get the balance for an address
 createblockchain -address ADDRESS creates a blockchain and sends genesis reward to address
 printchain - Prints the blocks in the chain
 send -from FROM -to TO -amount AMOUNT -mine - Send amount of coins. Then -mine flag is set, mine off of this node
 createwallet - Creates a new Wallet
 listaddresses - Lists the addresses in our wallet file
 reindexutxo - Rebuilds the UTXO set
 startnode -miner ADDRESS - Start a node with ID specified in NODE_ID env. var. -miner enables mining

BadgerDB

This blockchain implementation uses BadgerDB, a fast, persistent key-value store written in Go. BadgerDB is chosen for its efficient performance and reliability in handling large volumes of data, making it suitable for blockchain storage needs.

Key Features of BadgerDB

• Fast Reads and Writes: BadgerDB provides high-performance key-value access, crucial for the rapid querying and updating required by a blockchain.
• Persistent Storage: It ensures that blockchain data is stored reliably across restarts, using an append-only log and a memory table.
• Low Overhead: Designed with a focus on minimal memory overhead and efficient disk usage.
• Transaction Support: Supports ACID transactions to ensure data integrity during updates.

How BadgerDB is Used in the Project

• Blockchain Data Storage: Blocks, transactions, and UTXO sets are stored in BadgerDB for efficient querying and persistence.
• Reindexing: The reindexutxo command rebuilds the UTXO set by scanning and reindexing data stored in BadgerDB.
• State Management: Maintains blockchain state and history through BadgerDB’s transaction and snapshot capabilities.

Consensus

The consensus algorithm is a simple implementation of Proof of Work.

Wallet System

The wallet system provides the following features:

• Key pair generation using Elliptic Curve Digital Signature Algorithm (ECDSA)
• Public address generation with version byte and checksum
• Address validation
• Wallet serialization and deserialization using gob encoding
• Multi-wallet management
• Wallet persistence and recovery from file storage

Resources

• Golang program to implement a Merkle tree
• Base58 - An easy-to-share set of characters
• Building a Blockchain in Golang