  In this article, we present Ariadne, a privacy-preserving communication
network layer protocol that uses a source routing approach to avoid relying on
trusted third parties. In Ariadne, a source node willing to send anonymized
network traffic to a destination uses a path consisting in nodes with which it
has pre-shared symmetric keys. Temporary keys derived from those pre-shared
keys to protect communication privacy using onion routing techniques, ensuring
session unlinkability for packets following the same path.
  Ariadne enhances previous approaches to preserve communication privacy by
introducing two novelties. First, the source route is encoded in a fixed size,
sequentially encrypted vector of routing information elements, in which the
elements' positions in the vector are pseudo-randomly permuted. Second, the
temporary keys used to process the packets on the path are referenced using
mutually known encrypted patterns. This avoids the use of an explicit key
reference that could be used to de-anonymize the communications.
