sdns-calculator

DNS Stamp calculator component for Python. This tool generates DNS Stamps (for DoH/DoT/DoQ) by retrieving server certificates and computing necessary hashes locally.

Note: This tool requires an active internet connection to retrieve the server's SSL/TLS certificate, which is essential for generating the DNS Stamp. The calculation of the DNS Stamp itself is performed locally after the certificate is obtained.

• Thanks to jedisct1.
• Code implementations sourced from stamps-specifications

Why

This project was created to provide a local solution for generating DNS Stamps, particularly when direct certificate and hash computation through tools like dnscrypt-proxy is challenging. It aims to fill the gap for users seeking a straightforward, script-based approach.

Use

1. Install Python (3.7+)
2. Install the cryptography Python module: pip install cryptography
3. Download the script for your language (e.g., sdns-calculator.py)
4. Run it from your terminal: python sdns-calculator.py

Additionally, you can now select "Certificate Info" (option 5) to retrieve detailed server certificate information (Subject, Issuer, Serial Number, Validity, SHA256 Fingerprint, and TBS SHA256 Hash) for DoH/DoT protocols.

Important Note for Windows Users: If you encounter an ImportError: DLL load failed while importing _rust: The specified procedure could not be found. error when running the script, it is highly likely that your system is missing or has an outdated Microsoft Visual C++ Redistributable package. The cryptography library, which sdns-calculator depends on for secure operations, relies on these runtime components. To resolve this issue:

1. Download and install the latest Microsoft Visual C++ Redistributable
   • You can find the official download here: Microsoft Visual C++ Redistributable
   • It's generally recommended to download and install both the x86 and x64 versions, even if your Python installation is 64-bit, to ensure full compatibility.
2. Restart your computer after installation to ensure the changes take effect system-wide.
3. (Optional but recommended) If you've already tried to run the script and encountered the error before installing the redistributable, it's a good idea to reinstall cryptography after installing the redistributable: pip install --force-reinstall cryptography

If you encounter any problems during use, please submit your issues.