Reimplementing Tor from Scratch for a Single-Hop Proxy

3 months ago

The author, a student, needed a fast VPN for mundane tasks like accessing email and installing Linux packages at school, without the anonymity features of Tor.
Tor's multi-hop routing was too slow, leading the author to explore connecting directly to an exit node, which Tor intentionally disables for security reasons.
The author discovered that Tor blocks direct client connections to exit nodes by checking identity digests to prevent single-hop proxy usage.
By starting a relay node and using its keys, the author bypassed Tor's restrictions to establish a direct connection to an exit node, improving speed.
The project involved reimplementing Tor from scratch in C++ for better control and debugging, focusing on cryptography and networking.
Key steps included TLS handshakes, version exchanges, certificate verification, and key exchanges to establish a secure connection.
The author successfully benchmarked the custom implementation (Kurrat) against Tor Browser, finding it faster for their needs.
The implementation emphasizes error handling with std::optional and modular design for portability and maintainability.
The code is open-source, with contributions and installation instructions available on GitHub.

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