报告1题目：Secure Replication-Based Outsourced Computation Using Smart Contracts against Lazy Contractors

报告人：Willy Susilo教授

报告地点：腾讯会议 (453 966 184)

报告时间：2023年5月13日 9:00

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报告内容：

         The Replication-Based Outsourced Computation (RBOC) mechanism allows clients to outsource computing jobs to multiple contractors, with payment for honest contractors based on a majority vote. However, the traditional RBOC system suffers from issues with client privacy leakage, computation burden, and lazy contractors. To address these challenges, we propose a secure RBOC system that uses public-key encryption with equality tests (PKEET) via smart contracts, ensuring stability while protecting data privacy. This system effectively solves the privacy and computation burden problems but remains vulnerable to lazy contractor attacks, the root cause for which is that the existing PKEET schemes suffer from this type of attack. To solve this issue, we introduce PKEET against lazy encryptors (PKEET-LE), which provides security against lazy encryptors who aim to forge ciphertexts for a given ciphertext to pass the equality test between them without knowing the knowledge of the underlying plaintext. We construct a provably secure PKEET-LE scheme and evaluate its performance, demonstrating its practicality in the RBOC system using smart contracts.

报告人介绍：

        Willy Susilo (IEEE Fellow’2021) received the Ph.D. degree in computer science from the University of Wollongong, Australia. He is currently a Distinguished Professor and the Head of the School of Computing and Information Technology and the Director of the Institute of Cybersecurity and Cryptology, University of Wollongong. He has published over 400 research papers in the area of cybersecurity and cryptology. His main research interests include cybersecurity, cryptography, and information security. He was a recipient of the Australian Research Council (ARC) Future Fellow by the ARC and the Researcher of the Year Award by the University of Wollongong in 2016. He is the Editor-in-Chief of the Information journal. He has served as a program committee member in dozens of international conferences. He is currently serving as an Associate Editor in several international journals, including the ACM Computing Survey and the International Journal of Information Security (Springer). His work has been cited over 24,000 times in Google Scholar.

报告2题目: 随机数对密码学的影响

报告人：郭福春 教授

报告地点：腾讯会议 (453 966 184)

报告时间：2023年5月13日 13:00

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报告内容： 

     密码学在方案和协议的构造中经常使用随机数。虽然随机数处处可见，但在不同的方案里，其作用可能不一样。在本次报告里，我将系统介绍两方面的知识点。一是随机数的五大类作用；二是随机数在应用中可能出现的两大类问题。本次报告的目的是帮助密码学研究新生进一步打好密码学基础。

报告人介绍：

     郭福春，澳大利亚卧龙岗大学副教授，澳大利亚ARC DECRA Fellow， ARC Future Fellow。郭博士的密码学研究始于2005年并一直专注于公钥密码学方向的研究，特别是方案构造及安全归约理论技术。郭福春教授发表密码学相关学术论文若干篇以及中英两部著作《Introduction to Security Reduction》和《数字签名密史：从急需到有趣》。