Source and transaction privacy in blockchain systems

Privacy in blockchains

We study transaction source privacy and transaction content privacy in blockchain systems.

Blockchain-based networks are often concerned with privacy. Two common types of privacy in blockchain networks are (1) transaction source privacy, and (2) transaction content privacy. Research has shown that Bitcoin, the most prominent cryptocurrency, cannot easily provide these privacy types. Hence, new protocols have been proposed. For example, Dandelion++ is a solution to the source privacy vulnerability in Bitcoin.

Practical systems, however, need to provide multiple privacy guarantees at the same time. To the best of our knowledge, source privacy and content privacy have not been considered simultaneously in the literature. Moreover, we conjecture that the cryptocurrency protocols, such as those that use a Dandelion++ network design for transaction content privacy could be susceptible to attacks against both types of privacy and also to performance attacks. Our focus in this project is on MimbleWimble-style protocols such as Beam and Grin. In this project, we will implement and validate different attacks against these existing privacy-focused protocols, and provide mitigations to those attacks. We will also explore the formalization of source and content privacy to better understand their relationship.

Additional Information

People: Seyed Ali Tabatabaee

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Systopia lab is supported by a number of government and industrial sources, including Cisco Systems, the Communications Security Establishment Canada, Intel Research, the National Sciences and Engineering Research Council of Canada (NSERC), Network Appliance, Office of the Privacy Commissioner of Canada, and the National Science Foundation (NSF).