  IOTA is a distributed ledger technology that uses a Directed Acyclic Graph
(DAG) structure called the Tangle. It is known for its efficiency and is widely
used in the Internet of Things (IoT) environment. Tangle can be configured by
utilizing the tip selection process. Due to performance issues with light
nodes, full nodes are being asked to perform the tip selections of light nodes.
However, in this paper, we demonstrate that tip selection can be exploited to
compromise users' privacy. An adversary full node can associate a transaction
with the identity of a light node by comparing the light node's request with
its ledger. We show that these types of attacks are not only viable in the
current IOTA environment but also in IOTA 2.0 and the privacy improvement being
studied. We also provide solutions to mitigate these attacks and propose ways
to enhance anonymity in the IOTA network while maintaining efficiency and
scalability.
