Prof. Meiqin Wang

Title: Towards New Symmetric-Key Ciphers


Meiqin Wang is Executive Vice-President of the School of Cyberspace Security,Shandong University and Vice-Director of Key Laboratory of Cryptologic Technology and Information Security,Ministry of Education, Shandong University. She received her PhD degree in Information Security from Shandong University. Her current research interests are cryptanalysis and design of the symmetric-key cipher. She received the first-class National Scientific and Technological Progress Award in 2021. She has published more than 70 high-level papers in peer-reviewed journals and conferences, including 20 papers in EUROCRTPT, ASIACRYPT and FSE. She has been the program committee of many international conferences, such as ASIACRYPT and FSE etc


The symmetric-key cipher is one of the most important cryptographic primitives deployed in tremendous devices due to its efficiency and security. A traditional paradigm of designing symmetric-key ciphers such as AES is usually to set up a security target first and then optimize the hardware and software implementations. Such a paradigm is suitable to design ciphers for standard execution environments. However, with the rapid development of IoT, 5G networks, and privacy computations, ciphers that run in such execution environment are required strict high-performance parameters such as a smaller chip area, lower encryption latency, lower power consumption, smaller AND depths, etc. Strict requirements for these criteria force us to leverage new design paradigms.

Prof. Juan A. Garay

Title: Cryptography in the Blockchain Era


Since Fall ’17, Juan A. Garay is a full professor at Texas A&M University’s Computer Science & Engineering Department. Previously, after receiving his PhD in Computer Science from Penn State, he was a postdoc at the Weizmann Institute of Science (Israel), and held research positions at the IBM T.J. Watson Research Center, Bell Labs, AT&T Labs–Research, and Yahoo Research. His current research interests include both foundational and applied aspects of cryptography and information security. He is the author of over 170 published works (including articles, patents, and edited volumes) in the areas of cryptography, network security, distributed computing, and algorithms; has been involved in the design, analysis and implementation of a variety of secure systems; and is the recipient of a Thomas A. Edison Patent Award, two Bell Labs Teamwork Awards, an IBM Outstanding Technical Achievement Award, and an IBM Research Division Award. Dr. Garay has served on the program committees of numerous conferences and international panels—including co- chairing Crypto 2013 and 2014, the discipline’s premier conference. He is a Fellow of the International Association for Cryptologic Research (IACR).


The advent of blockchain protocols such as Bitcoin has ignited much excitement, not only for their realization of novel financial instruments, but also for offering alternative solutions to classical problems in fault-tolerant distributed computing and cryptographic protocols. Underlying many of such protocols is a primitive known as “proof of work” (PoW), which for over 20 years has been liberally applied in the cryptography and security literature to a variety of settings, including spam mitigation, sybil attacks, and denial of service protection; its role in the design of blockchain-based protocols, however, is arguably its most impactful application. At a high level, the way PoWs enable such protocols is by slowing message passing for all parties indiscriminately, thus generating opportunities for honest parties’ views to converge, under the assumption that their aggregate computational power exceeds that of the adversary.

This talk comprises two parts. First, despite the evolution of our understanding of the PoW primitive, pinning down the exact properties sufficient to prove the security of Bitcoin and related protocols has been elusive. In this talk we identify such properties, and then construct a protocol whose security can be reduced to them in the standard model, assuming a common reference string (CRS — cf. a “genesis” block). All previous protocols rely on the “random oracle” methodology.

Second, regarding the realizability of two important problems in the area of cryptographic protocols — Byzantine agreement (BA) and secure multiparty computation (MPC) — we show how PoW blockchains allow to realize them even in the presence of a minority (i.e., t < n/2) of corrupted parties, as long as the majority of the computation resources remain in honest hands, while “clasicaly,” protocols can only tolerate up to t < n/3 corruptions in the absence of a private-state setup (e.g., a public-key infrastructure). We resolve this apparent contradiction with a new paradigm we call “Resource-Restricted Cryptography.”

The bulk of this talk is based on joint work with Aggelos Kiayias, Rafail Ostrovsky, Giorgos Panagiotakos and Vassilis Zikas.