CAREER: Towards Privacy and Availability of Inter-blockchain Communication

现在已经很明显，区块链代表的不仅仅是一项金融创新。有创新的公共或私人区块链解决方案，适用于供应链、物联网等。在我们高度互联的世界中，这些解决方案很快将不可避免地相互作用。与今天的互联网类似，这最终将导致形成一个区块链网络，其中交易跨不同的区块链流动。一些特别的工业努力已经在这个方向上开始；然而，缺乏科学的严谨性，隐私和可用性问题普遍存在。该项目正式定义了提供不同隐私和可用性权衡的区块链间通信(IBC)概念，并通过开发低开销密码和/或密码经济解决方案安全地实现了这些概念在现实世界中的使用。该项目的新颖性包括对IBC原语的仔细抽象，提供隐私和可用性之间创新权衡的高效协议设计，以及对提议的工具和协议的安全分析。随着区块链在未来几年连接起来，将出现许多进步，特别是以接入技术(例如，互联网传输协议的区块链对应)的形式出现，该项目的更广泛的意义和重要性包括为这些先进技术的发展提供强大、安全和隐私保护的通信平台。此外，随着当前区块链空间中利他主义的淡出和恶意活动的盛行，该项目的原则性方法将成为区块链之间交互的必要手段。本研究设计并实现了在存在恶意或易崩溃的连接器节点以及大规模活跃的网络级攻击者的情况下保护隐私的IBC协议。该项目还研究了隐私和非阻塞进度以及非源路由和虫洞攻击之间的反向关系，并开发了隐私感知蓝图和开源代码库，可以构成跨区块链交易的基础。调查人员积极与区块链社区互动(以出版物、研讨会、研讨会和课程材料的形式)，以展示隐私和可用性漏洞的严重性，并宣传开发的解决方案。通过提高对IBC隐私和可用性的基本了解，该项目实现了端到端的安全性，最终将增强公众对区块链互联网基础技术的信心，并将导致其快速接受跨不同域的分散和高度可用的资产跟踪。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.