Advances in Onion Routing: Description and backtracing/investigation problems

Onion routers were born about 10 years ago as a sort of blended military/research project. The main goal of it was the avoidance of traffic analysis (TA). TA is used in part to identify the remote IP addresses that a given host seeks to contact. This technique may have various purposes, from simple statistical analysis to illegal interception. In response, to protect personnel whose communications are being monitored by hostile forces, researchers from the US Naval Research Laboratory conceived a system, dubbed “Onion Routing”, that eludes the above two operations.In this author's opinion, the original “owners” of the project lost control of it. Software is freely available that enables anyone to utilize a network of onion routers. The result is a strong evolution (in terms of “privacy”) that is very difficult to manage, especially when an international investigation must be performed.