It has now become clear that blockchains represent much more than a financial innovation. There are innovative public or private blockchain solutions for supply chains, the "Internet of Things", and beyond. In our highly inter-connected world, it is inevitable that these solutions will soon have to interact with each other. Similar to the Internet today, this will eventually result in formation of a network of blockchains where transactions flow across disparate blockchains. Some ad hoc industrial efforts have already begun in this direction; however, the scientific rigor is missing, and privacy and availability issues are pervasive. This project formally defines inter-blockchain communication (IBC) notions offering different privacy and availability trade-offs and securely realizes those notions toward real-world use by developing low-overhead cryptographic and/or crypto-economic solutions. The project's novelties includes careful abstractions of IBC primitives, efficient protocol designs offering innovative trade-offs between privacy and availability, and security analyses for the proposed tools and protocols. As the blockchains get connected over the coming years, numerous advances, particularly in the form of access technologies (e.g., blockchain counterparts of Internet transport protocols) will emerge, and the project's broader significance and importance includes offering robust, secure, and privacy-preserving communication platforms for development of these advanced technologies. Furthermore, as the current altruism in the blockchain space fades out and malicious activities become prevalent, the project's principled approach will become a necessity for inter-blockchain interactions.
This research designs and implements privacy-preserving IBC protocols in presence of malicious or crash-prone connector nodes as well as large-scale active network-level attackers. The project also studies the inverse relationships between privacy and non-blocking progress, and non-source routing and wormhole attacks, and develops a privacy-aware blueprint and open-source code-base that can form the basis of the transactions across the blockchains. The investigators actively interact with the blockchain community (in the form of publications, seminars, workshops, and course materials) to demonstrate the severity of privacy and availability vulnerabilities, and to promote the developed solutions. By improving fundamental understanding of privacy and availability of IBC, this project enables its end-to-end security that will ultimately enhance public confidence in the technology underlying the internet of blockchains and will lead to its rapid acceptance for decentralized and highly-available asset tracking across different domains.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
