On the Security of the Dandelion Protocol

In this paper, we review the peer-to-peer blockchain transaction protocol, Dandelion, and develop an oracle-based model for its network and security. We formalize a series of security and functional criteria, such as unforgeability, non-repudiation, and immutability, into security experiments. In our model, we consider a quantum-capable adversary who seeks to undermine any of the security criteria while using oracles to simulate and interact with the Dandelion network. We then prove the security of Dandelion in our model with a series of (tight) security reductions as our main result. In addition, we prove that Dandelion is resistant to double-spending attacks.