http://7fa6xlti73nrpxl6cykao4wp7g3bg4624ghrtdomlvkeivvwclv2iyad.onion/related-comm.html
This loss of sender/receiver anonymity plagues all systems which include
external clients which interact through a separate communications
channel - that is, we can define some distinct edge of the channel. If
an adversary can monitor this edge link or the first-hop node within the
channel, this observer gains agent-message correlation. Obviously, the
ability to monitor this link or node depends on the adversary's
resources and the number of links and nodes which exist. ...