地点：长安校区 文津楼三段6层628报告厅

主办单位：永利yl23411 网络信息安全团队

报告题目：Secret sharing based on hyperplane geometry with its application in cryptographic protocols

报告时间：2019年6月6日（星期四） 8:30-10:00

报告人：夏喆 副教授

报告内容简介

In this talk, we revisit the secret sharing based on hyperplane geometry introduced by Blakley, and introduce its potentials that were not known by the crypto research community before. First, we show how it can be used to design threshold Paillier encryption so that the interpolation over Z_{\phi(n)} problem can be completely avoided. Second, we show that it has computational advantages over the secret sharing based on polynomial interpolation in (n, n) threshold secret sharing, and this attractive feature has many applications in designing cryptographic protocols, e.g. proactive secret sharing and attribute-based encryptions.

报告人简介

         夏喆，男，1982年7月出生，博士、武汉理工大学副教授、硕士生导师。2009年获得英国萨里大学博士学位，2009年至2013年在英国萨里大学从事博士后研究，2017年至2018年在澳大利亚伍伦贡大学进行访问学习，主要研究方向为密码学和信息安全。近年来在TIFS、DCC、IET Information Security、ACISP等国际期刊会议上发表学术论文40余篇，曾担任澳大利亚学术委员会（ARC）信息安全方向评审及ESORICS, EVT, Vote-ID等国际学术会议程序委员会委员。目前担任中国计算机学会推荐国际期刊《Journal of Information Security and Application》的副主编（Associate Editor），以及多个信息安全专刊的编委。

报告题目：Tutorial Talk on Polynomial-based Cryptography

报告时间：2019年6月6日（星期四） 10:10

报告人：Lein Harn 教授

报告内容简介

This tutorial talk will cover following topics.

1. What is polynomial-based cryptography?

▪ Univariate polynomial has been used in (t, n) secret sharing scheme.

▪ Bivariate polynomials, including both symmetric and asymmetric bivariate polynomials, have been used to establish pairwise keys of users.

▪ The threshold of bivariate polynomials.

1. Why do we study polynomial-based cryptography?

   ▪ Polynomial-based cryptography is suitable for future development (after quantum computing).

   ▪ Polynomial-based cryptography is suitable for current development (faster than public-key computation).

2. Why polynomial evaluation is much faster than public-key evaluations?

   ▪ The complexity of polynomial evaluation based on Horner’s rule is compared with modular exponentiation based on square-and-multiplication.

▪ I will include both theoretical and experimental results to support above claims.

1. What polynomial-based cryptography can provide?

   ▪ Secure secret reconstruction with confidentiality

   ▪ Secret sharing over network

   ▪ Threshold changeable secret sharing

   ▪ Group authentication and group key establishment

   ▪ Enhance key establishment in wireless sensor network with probabilistic sensor capture attack

2. What is the limitation of polynomial-based cryptography?

   ▪ After capturing t or more than t shares, attacker can recover the secret polynomial.

3. Future research

   ▪ Research in extension to threshold cryptography based on bivariate polynomial including threshold signature and threshold encryption.

   ▪ Research in secret sharing based on bivariate polynomial including multi-secret secret sharing, verifiable secret sharing, rational secret sharing.

   ▪ Research in group-oriented cryptography based on bivariate polynomial including what other group-oriented protocols can be developed based on bivariate polynomials.

   ▪ Research on multi-variable polynomial cryptography including general extension to multi-variate polynomials.

   ▪ Research on network applications based on bivariate polynomial including cloud computing, distributed database, IoT, wireless sensor networks, vehicle networks.

报告人简介

 Lein Harn received the B.S. degree in electrical engineering from the National Taiwan University in 1977, the M.S. degree in electrical engineering from the State University of New York-Stony Brook in 1980, and the Ph.D. degree in electrical engineering from the University of Minnesota in 1984. In 1984, he joined the Department of Electrical and Computer Engineering, University of Missouri- Columbia as an Assistant Professor, and in 1995, he has been promoted as a Full Professor, University of Missouri, Kansas City (UMKC). While at UMKC, he went on development leave to work in Racal Data Group, Florida for a year. His research interests include cryptography, network security, and wireless communication security. He has published over hundred research journal papers on digital signature design and applications, and wireless and network security.  He has written two books on security. He is currently investigating new ways of using secret sharing in various applications.