CAREER: Temporal Cryptography and Verifiable Lotteries

彩票每年用于分发数十亿美元的现金奖，以及重要的资源，包括移民签证，学校安置和法官上诉案件的分配。人们希望公众相信，这些彩票是公平进行的，具体来说，结果是随机的，没有偏见，在正式宣布之前是不可预测的或秘密的。今天，几乎所有的彩票要么不向公众提供任何技术保证，要么依赖于古老的物理随机性生成方法，如滚动骰子或旋转轮盘。该项目将为加密验证彩票奠定坚实的科学基础，即使对远程观察者也能提供强有力的保证，即彩票是公平的。为此，该项目将从新兴的时间（基于时间的）密码学领域开发新工具，包括可验证的延迟函数和定时承诺。时态密码学是分布式随机性协议和其他应用的强大构建块，但关键问题仍然是如何参数化和分析这样的协议。其次，该项目将发展时间密码学的理论，并考虑其与随机生成，共识和一般多方计算协议的经典边界和不可能结果的关系。最后，该项目将通过对彩票机制的实证研究和用户研究，了解当前对加密验证的期望和反应，从而建立对彩票需求和用户期望的实际理解。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Lotteries are used to distribute billions of dollars annually in cash prizes, as well as important resources including immigration visas, school placements and assignments of judges to appeal cases. One would like to have public confidence that these lotteries were conducted fairly, specifically that the results were random and without bias and that they were not predictable or secretly known prior to their official announcement. Today, nearly all lotteries either provide no technical assurance to the public whatsoever or rely on ancient means of physical randomness generation such as rolling dice or spinning wheels. This project will build a solid scientific foundation for cryptographically verifiable lotteries that can provide strong assurance, even to remote observers, that a lottery was fair.To do so, this project will develop new tools from the emerging field of temporal (time-based) cryptography, including verifiable delay functions and timed commitments. Temporal cryptography is a powerful building block for distributed randomness protocols and other applications, but key questions remain on how to parameterize and analyze such protocols. Second, the project will develop the theory of temporal cryptography and consider its relation to classic bounds and impossibility results on randomness generation, consensus and general multiparty computation protocols. Finally, this project will build a practical understanding of lottery requirements and user expectations through empirical study of lottery mechanisms and user studies to understand current expectations and reactions to cryptographic verifiability.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.