Bitcoin Cryptography Implementation

Simple Bitcoin cryptography implementation that generates BTC addresses from scratch and sends custom transactions with Bitcoin Core RPC.

🎥 Featured in my YouTube video: https://youtu.be/z2Ju7pcE6wo

Features

• Address Generation (main.ipynb): Generate Bitcoin addresses from private keys using secp256k1

  • Legacy addresses (P2PKH)
  • SegWit addresses (Bech32)
  • Private key formats: decimal, hex, WIF

• Transaction Sending (send.ipynb): Send Bitcoin with custom messages via Bitcoin Core RPC

  • OP_RETURN data embedding
  • PSBT workflow

Quick Start

1. Install dependencies:

   pip install -r requirements.txt

2. For transaction sending, create .env file:

   RPC_USER=your_username
   RPC_PASSWORD=your_password
   RPC_HOST=127.0.0.1
   RPC_PORT=8332

3. Run the notebooks:

   • main.ipynb - Generate Bitcoin addresses
   • send.ipynb - Send transactions (requires Bitcoin Core)

Importing Addresses to Bitcoin Core

After generating addresses, you can import them to Bitcoin Core to monitor transactions:

1. Get descriptor info - Open Bitcoin Core console and run:

   getdescriptorinfo "combo(WIF)"
   

   Example:

   getdescriptorinfo "combo(Kz6dh8Ny4HuCDrWEsyBZsUUjz16ab1hmgR5ihvKFx7wGGFibe7Cc)"
   

   Response:

   {
     "descriptor": "combo(02ffd6ef90a5bb4ca138aaad516560aa80157ae0629a27099660dfd5039bc3fa2b)#l3la8e8y",
     "checksum": "04fk0myz",
     "isrange": false,
     "issolvable": true,
     "hasprivatekeys": true
   }

2. Import the descriptor - Use the descriptor with checksum:

   importdescriptors '[{"desc": "combo(WIF)#DESCRIPTOR", "timestamp": "now"}]'
   

   Example:

   importdescriptors '[{"desc": "combo(02ffd6ef90a5bb4ca138aaad516560aa80157ae0629a27099660dfd5039bc3fa2b)#l3la8e8y", "timestamp": "now"}]'
   

Note: The timestamp parameter determines when to start scanning for transactions:

• "now" - Only scan for new transactions from current time
• 0 - Scan from the beginning of the blockchain (full rescan)
• Unix timestamp - Scan from a specific date (e.g., 1640995200 for Jan 1, 2022)

The descriptor format includes the checksum after the # symbol for verification.

Dependencies

• ecdsa - Elliptic curve cryptography
• base58 - Address encoding
• bech32 - SegWit address encoding
• bitcoinrpc - Bitcoin Core RPC client

Warning

⚠️ Educational purposes only. Do not use for real funds.