I made a new cryptosystem called OK-Mixnet. It has “perfect” security, as opposed to the usual pretty-good security. (Of course, it’s not magic–if your computer is hacked, the cryptosystem isn’t gonna protect your data). Despite the name, it’s not really a mixnet per se, it just similarly defends against SIGINT.
A writeup is here: https://za3k.com/ok-mixnet.md
The alpha codebase is here: https://github.com/za3k/ok-mixnet
Let me know if you’d like to join the open alpha. Email me your username and IP (you’ll need to forward a port).