Blockchain Wallet

Overview

A Python-based educational blockchain wallet implementation that demonstrates core cryptocurrency concepts including key generation, transaction management, and basic blockchain operations. The project provides a command-line interface for users to create wallets, manage private keys, send transactions, and interact with a simplified blockchain network. This is designed as a learning tool to understand blockchain fundamentals rather than a production-ready cryptocurrency wallet.

User Preferences

Preferred communication style: Simple, everyday language.

System Architecture

Core Components

Wallet Management

• Uses ECDSA cryptography with SECP256k1 curve for key generation and signing
• Implements address creation through public key hashing with Base58 encoding
• Provides secure private key storage with password-based encryption using PBKDF2 and Fernet
• Supports wallet import/export functionality for key portability

Transaction System

• Implements digital signature-based transaction validation
• Includes transaction pooling mechanism for managing pending transactions
• Supports basic transaction features including amounts, fees, and optional messages
• Provides transaction history tracking and status management

Blockchain Implementation

• Simplified proof-of-work consensus mechanism with adjustable mining difficulty
• Block structure includes transaction data, timestamps, and cryptographic hashing
• Chain validation logic to ensure blockchain integrity
• Mining functionality with progress reporting and nonce-based hash targeting

Command Line Interface

• Interactive menu-driven user experience for wallet operations
• Real-time wallet status display including balance and unlock state
• Comprehensive error handling and user feedback
• Secure password input for sensitive operations

Security Architecture

Cryptographic Security

• ECDSA digital signatures for transaction authenticity
• SHA-256 hashing for block and transaction integrity
• Secure random number generation for private key creation
• Password-based key derivation for wallet file encryption

Access Control

• Wallet lock/unlock mechanism to protect private keys in memory
• Encrypted wallet file storage with user-defined passwords
• Private key exposure controls with user confirmation requirements

Data Storage

File-Based Storage

• JSON format for wallet data persistence
• Encrypted private key storage using cryptography library
• Transaction history maintained within wallet files
• Blockchain state persistence across sessions

External Dependencies

Cryptographic Libraries

• ecdsa - Elliptic curve digital signature operations using SECP256k1
• cryptography - Advanced encryption, key derivation, and secure storage
• base58 - Bitcoin-style address encoding for user-friendly addresses

Standard Libraries

• hashlib - SHA-256 hashing for blockchain operations
• json - Data serialization for wallet and transaction storage
• secrets - Cryptographically secure random number generation
• getpass - Secure password input without echo
• time - Timestamp generation for blocks and transactions

Development Tools

• Python 3.x runtime environment
• Standard library modules for file I/O, error handling, and system operations