Mix Networks

High-Latency Anonymous Communication

What Are Mix Networks?

Mix networks (mixnets) provide stronger anonymity than Tor by adding delays and mixing messages together. They resist traffic analysis by breaking the timing correlation between input and output messages.

How Mixing Works

Mix Node Operation
Messages arrive: A, B, C, D
                 ↓
Mix node collects batch
                 ↓
Decrypt layer, reorder randomly
                 ↓
Messages leave: C, A, D, B (random order)

Observer cannot correlate input ↔ output

Mixnets vs Tor

AspectMix NetworksTor
LatencyHigh (minutes-hours)Low (sub-second)
Traffic AnalysisStrong resistanceVulnerable
Use CaseEmail, messagingWeb browsing
Real-timeNoYes

Modern Implementations

Nym

Modern mixnet with incentive layer

Active

Loopix

Continuous cover traffic design

Research

Mixmaster/Mixminion

Classic anonymous remailers

Legacy

Key Properties

  • Batch processing breaks timing
  • Cover traffic hides real messages
  • Multiple mix nodes for cascade
  • Resistant to global adversary
  • Pool mixing (Chaumian mixes)