A step-by-step project that builds a simplified version of Bitcoin from scratch using pure Python code. Designed to help developers deeply understand Bitcoin's core cryptography, data structures, and consensus mechanisms through hands-on practice.

This project is specifically designed for developers who want to understand Bitcoin principles through code, not as a production-ready wallet or node.

• Progressive Learning: From step1 to step10, each script focuses on a single core concept.
• Code as Documentation: High-quality, educational comments explain the "why" behind every line of code.
• Core Logic: Focus on cryptography, transaction structure (UTXO), block construction, and Proof of Work (PoW).
• Simplified Non-essentials: Temporarily ignores complex P2P networking and Base58 encoding for a smoother learning curve.

This project requires Python 3.9+.

1. Clone or Download the Project

   git clone https://github.com/picasso250/my-bitcoin.git
   cd my-bitcoin
   

2. Install Dependencies The project depends on the ecdsa library for elliptic curve digital signatures. We recommend using a virtual environment.

   # (Optional) Create and activate virtual environment
   python3 -m venv venv
   source venv/bin/activate  # macOS/Linux
   # venv\Scripts\activate   # Windows
   
   # Install all dependencies
   pip install -r requirements.txt
   

We strongly recommend executing and reading each script in numerical order, as knowledge from later steps builds upon earlier ones.

💡 Learning Tip: Pair Programming with AI

During your learning journey, we especially encourage you to interact frequently with AI assistants like Gemini. When you encounter code you don't understand, unclear concepts, or want to explore cryptographic details more deeply, don't hesitate to ask. Sharing code snippets and your questions directly with AI is an excellent way to consolidate knowledge and spark inspiration. Making this a habit will greatly accelerate your learning process.

• step1_generate_keys.py: Generate Bitcoin private and public keys.
• step2_sign_and_verify.py: Understand the core process of digital signatures.
• step3_public_key_to_address.py: Derive addresses from public keys.
• step4_build_simple_transaction.py: Build a structured transaction.
• step5_create_a_block.py: Pack signed transactions into a block.
• step6_mine_a_block.py: Introduce Proof of Work (mining) and block rewards.
• step7_single_utxo_transaction.py: Introduce the core concept of UTXO (single input, multiple outputs).
• step8_multi_input_utxo_transaction.py: Implement realistic payment scenarios (multiple inputs).
• step9_coinbase_in_utxo_block.py: Complete demonstration of Coinbase transactions and miner fees.
• step10_simulated_network_consensus.py: Simulate how multiple nodes achieve consensus through broadcasting.

Open your terminal and execute in order:

python step1_generate_keys.py
python step2_sign_and_verify.py
# ...and so on

Welcome any improvement suggestions or bug fixes! Please contribute through Pull Requests or Issues.