Glossary
What is cover traffic?
Cover traffic is decoy messages mixed in with real ones so that an observer cannot tell when you are actually communicating.
Even with content encrypted and senders hidden, the timing of your messages can leak your activity pattern. Cover traffic defeats this by producing decoy transactions indistinguishable from real ones.
PrivaMesh uses cover traffic so that timing and frequency analysis on the chain gets no usable signal - an observer cannot separate a genuine send from noise.
Traffic analysis is an old discipline and it does not need message content. Volume and timing alone reveal working hours, time zones, sleep patterns, and the moment something unusual happens. A sudden burst of activity at 3am is information, and encryption does nothing to hide it.
Cover traffic works by ensuring the observable signal is constant regardless of whether you are communicating. Decoy transactions are indistinguishable from real ones - same size, same shape, same kind of destination - so an observer counting activity learns your cover traffic rate rather than your behaviour.
The cost is real and worth stating: decoys consume bandwidth and, on a fee-based transport, a small amount of money to send nothing. That is the price of removing the timing channel, and it is the reason most messengers skip it and accept that their users’ activity patterns are visible.
Primary sources
- Signal: sealed senderSignal’s approach to hiding sender metadata, for comparison with stealth addressing.