The Bitcoin P2P network currently represents a reference benchmark for modern cryptocurrencies. Its underlying protocol
defnes how transactions and blocks are distributed through all participating nodes. To protect user privacy, the identity of
the node originating a message is kept hidden. However, an adversary observing the whole network can analyze the spread
pattern of a transaction to trace it back to its source. This is possible thanks to the so-called rumor centrality, which is caused
by ...
The Bitcoin P2P network currently represents a reference benchmark for modern cryptocurrencies. Its underlying protocol
defnes how transactions and blocks are distributed through all participating nodes. To protect user privacy, the identity of
the node originating a message is kept hidden. However, an adversary observing the whole network can analyze the spread
pattern of a transaction to trace it back to its source. This is possible thanks to the so-called rumor centrality, which is caused
by the symmetry in the spreading of gossip-like protocols. Recent works try to address this issue by breaking the symmetry
of the Difusion protocol, currently used in Bitcoin, and leveraging proxied broadcast. Nonetheless, the complexity of their
design can be a barrier to their adoption in real life. In this work, we propose Clover, a novel transaction relay protocol that
protects the source of transaction messages with a simple, yet efective, design. Compared to previous solutions, our protocol
does not require building propagation graphs, and reduces the ability of the adversary to gain precision by opening multiple connections towards the same node. Experimental results show that the deanonymization accuracy of an eavesdropper
adversary against Clover is up to 10 times smaller compared to Difusion.
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