You raise a valid concern about Byzantine nodes in the mix network. Our protocol design acknowledges this challenge and incorporates several mitigations:
- Random path selection: Senders choose mix nodes randomly, reducing the probability of selecting an all-Byzantine path.
- Configurable path length: Users can adjust the number of mix nodes in their path, balancing anonymity and Byzantine resistance.
- Deanonymization probability analysis: We’re conducting analyses on deanonymization probabilities under various attack models, including AS-level adversaries. Our preliminary results suggest that with proper implementation of Sphinx packet format, random delays, and careful path selection (using 3-4 distinct nodes), we can maintain a low deanonymization probability even against strong adversaries controlling a significant fraction of the network.
- Reputation system (planned): We’re exploring reputation mechanisms to help identify and avoid potentially malicious nodes.
While these measures significantly reduce risks, they don’t eliminate them entirely. We’re actively researching additional Byzantine-resistant techniques and welcome community input on further improvements.
Ultimately, the protocol aims to provide strong anonymity guarantees while maintaining a balance with practical usability in decentralized networks.