Reused R Bitcoin

A Python-based toolset for detecting and analyzing repeated ECDSA or Schnorr nonces (r values) in Bitcoin transaction signatures. Nonce reuse is a critical cryptographic vulnerability that can lead to private key compromise. This actor is intended for security research, auditing, and educational purposes.

Overview

When a Bitcoin transaction is signed, a cryptographically secure random number called a nonce (k) is required. If the same nonce is reused with the same private key (resulting in a repeated r value in the signature), the signatures become mathematically linked. This allows anyone with the two signatures to potentially compute the private key, breaking the security of the address.

This tool scans blockchain data to identify such r-repeats, helping researchers and developers audit key safety, investigate vulnerabilities, and understand failure modes in signing implementations.

Key Features

• Detects ECDSA & Schnorr Nonce Reuse: Identifies repeated r values across transactions for a given set of Bitcoin addresses.
• Blockchain Data Fetching: Can pull transaction data from public blockchain APIs or work with local datasets.
• Security-Focused: The tool itself does not collect, transmit, or store any personal user data or results.
• Educational Resource: Provides a practical means to study a well-known cryptographic vulnerability and its real-world occurrences.

How to Use

Prerequisites

• Python 3.10 or newer.
• Sufficient storage for blockchain data (size depends on analysis scope).
• Internet connection (if fetching live data).
• Required Python packages:
  bash pip install requests tqdm ecdsa

Basic Operation

The primary function is to check a list of Bitcoin addresses for nonce reuse. Prepare a text file (addresses.txt) with one address per line.

Run the main analysis script:

python find_r_repeats.py --input addresses.txt

The tool will fetch transaction history for each address, extract signatures, and compute r values to find duplicates.

Input/Output

• Input: A file containing Bitcoin addresses (one per line). The tool can also accept pre-downloaded transaction data in JSON format for offline analysis.
• Output: A report listing any addresses where repeated r values were detected, along with the transaction IDs (txids) of the vulnerable signatures. Output is typically printed to the console and can be redirected to a file.

Example Address List

The actor documentation includes a sample list of addresses historically associated with this vulnerability, such as:

1HXSnvNGK8oYQCyLDkpHNZ2sWPvFsYQcFU
112KZ24UgNndZqdnu2cXwXStSjtY78ZRUh
12ZXAga2nRxBECsMDjFypWuL9UkKEaS4Z3

Security & Responsibility Notice

️ Important: This tool is for research and educational purposes only. Understanding this vulnerability helps in building more secure systems. Any incorrect, malicious, or unauthorized use is solely the responsibility of the user.

Safety Recommendations:
* Use well-audited, up-to-date cryptographic libraries (e.g., libsecp256k1).
* Prefer correctly implemented RFC 6979 (deterministic nonce generation).
* Use reputable hardware wallets or HSMs for high-value keys.
* Never reuse a private key across different applications or blockchains.
* Avoid brainwallets or low-entropy passphrases for key generation.
* Monitor your own signatures for r-repeats as a defensive check.

You are encouraged to review the source code to verify its functionality and security. The tool operates read-only against public blockchain data.