l4v VS cryptography

Yes! https://github.com/seL4/l4v/tree/master/spec/haskell

Ah, and sorry, I forgot, I don't use any third party libs for the networking. It's all from scratch to be as efficient as possible, and usable over low-bandwidth links. I used a library for fetching network card details when using physical ethernet devices as interfaces, and I used the very well-regarde cryptography.io library for the cryptographic primitives that I use in the implementation.

When I try to install the Cryptography package for Python through either pip install cryptography or by downloading the package from their site and running python setup.py, I get the following error:

I know you mentioned it, but for anyone who hasn't read what happened with the cryptography package when they changed the backend to rely on Rust. I take no stance on the issue, but the drama of it is a fantastic read.

Here you go: https://github.com/pyca/cryptography/issues/5771 enjoy.

There's a discussion on Github issues of Cryptography lib if you want more details : https://github.com/pyca/cryptography/issues/6804

This cause issue when using some libraries (eg. Python cryptography : https://cryptography.io)

Yes, I would say that pyO3 + maturin or setuptools-rust is the most common setup nowadays. https://github.com/pyca/cryptography is an example for a mixed Rust + Python package.

You don't get the benefit of "security" by using version ranges. If anything, your builds must produce same result whether they're built a year later, tomorrow, or next month, when built from same source configuration. In fact, it's less secure because you might get an update that breaks entire API or builds (See: cryptography library update breaking entire ecosystem. a library that must be as stable as possible. What if it packaged malware instead?)