- [SoK: Secure Messaging](http://cacr.uwaterloo.ca/techreports/2015/cacr2015-02.pdf) - evaluation of current secure messaging solutions based on security, usability and adoption
- [The Differences Between Onion Routing and Mix Networks](https://crypto.is/blog/mix_and_onion_networks) - brief comparison
- [Anonymity Trilemma: Strong Anonymity, Low Bandwidth Overhead, Low Latency—Choose Two](https://eprint.iacr.org/2017/954.pdf) - on fundamental tradeoff for anonymous communication protocols
- [Briar](https://briarproject.org/) - messaging app employing several censorship-resitance techniques, like direct device-to-device comms (bluetooth, wifi), Tor routing