We are organizing a weekly seminar, Meet-in-the-Middle, from 18th August 2021. This seminar is held on each Wednesday from 16:00. The aim of this seminar is to create the diversification of the knowledge and to share and explore new research ideas in Computer Science and Mathematics among the researchers and the students. Each week, a designated speaker from IAI (Faculties and Students) or from other institutes will be delivering the talk. A prior notice about the topic is intimated a week before the talk.

Co-ordinator: Dr. Avijit Dutta (avijit.dutta@tcgcrest.org).

Online Meeting Link:

Meeting ID: 823 6262 7024
Passcode: 502333

All Previous Talks

  • Speaker: Dr. Tuhin Ghosh
    Affiliation: Harish-Chandra Research Institute
    Date: 24/01/2024
    Title: Inverse Problems and Invisibility Cloaking
    Abstract: I will start the talk by describing a few inverse problems that arise in several contexts. Solving inverse problems is in fact how we obtain a large part of our information about the world we live in. In the second part of the talk, I will discuss invisibility, addressing the question, “can we make objects invisible?” This has been a subject of human fascination and has to do with the non-unique aspect of the inverse problems.

  • Speaker: Dr. Sujoy Sinha Roy
    Affiliation: TU Graz, Austria
    Date: 17/01/2024
    Title: Introduction to the concept of homomorphic encryption and its hardware acceleration

  • Speaker: Dr. Arpita Patra
    Affiliation: IISc, Bangalore
    Date: 11/07/2024
    Title: Quadratic Multiparty Randomized Encodings Beyond Honest Majority and Their Applications
    Multiparty randomized encodings (Applebaum, Brakerski, and Tsabary, SICOMP 2021) reduce the task of securely computing a complicated multiparty functionality f to the task of securely computing a simpler functionality g. The reduction is non-interactive and preserves information-theoretic security against a passive (semi-honest) adversary, also referred to as privacy. The special case of a degree-2 encoding g (2MPRE) has recently found several applications to secure multiparty computation (MPC) with either information-theoretic security or making black-box access to cryptographic primitives. Unfortunately, as all known constructions are based on information-theoretic MPC protocols in the plain model, they can only be private with an honest majority. In this paper, we break the honest-majority barrier and present the first construction of general 2MPRE that remains secure in the presence of a dishonest majority. Our construction encodes every n-party functionality f by a 2MPRE that tolerates at most $t=\lfloor 2n/3\rfloor$ passive corruptions. We derive several applications including: (1) The first non-interactive client-server MPC protocol with perfect privacy against any coalition of a minority of the servers and up to t of the n clients; (2) Completeness of 3-party functionalities under non-interactive t-private reductions; and (3) A single-round t-private reduction from general-MPC to an ideal oblivious transfer (OT). These positive results partially resolve open questions that were posed in several previous works. We also show that t-private 2MPREs are necessary for solving (2) and (3), thus establishing new equivalence theorems between these three notions. Finally, we present a new approach for constructing fully-private 2MPREs based on multi-round protocols in the OT-hybrid model that achieve perfect privacy against active attacks. Moreover, by slightly restricting the power of the active adversary, we derive an equivalence between these notions. This forms a surprising, and quite unique, connection between a non-interactive passively-private primitive to an interactive actively-private primitive. Based on a joint work with Benny Applebaum, Yuval Ishai, Or Karni, accepted to CRYPTO’22.

  • Speaker: Prof. Mridul Nandi
    Affiliation: Professor, ISI Kolkata and Adjunct Professor, IAI, TCG CREST
    Date: 08/06/2023
    Title: Analysis of Recent Don Knuth’s Algorithm on Distinct Element Problem
    Abstract: In this talk, we address the Distinct Elements Problem in the context of streaming algorithms. The problem involves estimating the number of distinct elements in a given data stream (a_1, a_2,\ldots, a_m). A recent sampling-based algorithm proposed by Chakraborty et al. in 2022  (named CVM due to Professor Don E. Knuth)  has garnered significant interest and has even attracted the attention of renowned computer scientist Professor Don E. Knuth. He has proposed two algorithms D’ (a close variant of CVM) and D that are publicly available in https://www-cs-faculty.stanford.edu/~knuth/papers/cvm-note.pdfIn this talk, we describe a simple analysis of Algorithms D and D’. 

  • Speaker: Mr. Prabal Banerjee
    Affiliation: Co Founder at Avail
    Date: 30/05/2023
    Title: Addressing the Data Availability Problem in Blockchains
    Relevant Links: [Video]  [BoardWork]

  • Speaker: Dr. Arijit Ghosh
    Affiliation: Associate Professor, ISI Kolkata
    Date: 03/05/2023
    Title: Hyperplane cover of symmetry preserving subsets of the hypercube and its generalizations
    Relevant Links: [Video]  [BoardWork]

  • Speaker: Dr. Sourav Chakraborty
    Affiliation: Associate Professor, ISI Kolkata
    Date: 03/05/2023
    Title: Estimating the size of union of sets in streaming model
    Relevant Links: [Video]  [BoardWork]

  • Speaker: Dr. Prahllad Deb
    Affiliation: Postdoctoral Fellow at Ben-Gurion University of the Negev, Israel
    Date: 29/03/2023
    Title: Towards a noncommutative theory of Cowen-Douglas class of noncommuting operators

  • Speaker: Mr. Sagnik Nandy
    Affiliation: University of Pennsylvania
    Date: 11/01/2023
    Title: Orchestrated AMP: A novel way of Data Integration
    Relevant Links: [Video

  • Speaker: Dr. Debsoumya Chakraborti
    Affiliation: Post Doctoral Fellow at Institute for Basic Sciences (IBS), South Korea
    Title: Colorful combinatorics
    Relevant Links: [Video

  • Speaker: Prof. Mridul Nandi
    Affiliation: Professor, ISI Kolkata
    Date: 09/11/2022 
    Title: A Brief Overview of Streaming Algorithm
    Relevant Links: [Video]

  • Speaker: Dr. Payel Sadhukhan
    Affiliation: Post Doctoral Fellow, IAI, TCG CREST
    Date: 02/11/2022 
    Title: Random Walk-steered Majority Undersampling
    Relevant Links: [Video]

  • Speaker: Dr. Arun Maiti
    Affiliation: Post Doctoral Fellow, IIT Bombay
    Date: 12/10/2022
    Title: Cohomology of unordered flag manifolds
    Abstract: The (complex and real) complete flag manifolds are important objects in algebraic topology and geometry. The cohomology of these spaces is well known. Viewing complete flags as ordered bases, we obtain unordered complete flag manifolds by forgetting the ordering of the bases. Motivated by questions arising in algebraic topology and Banach geometry, we (jointly with Lorenzo Guerra) study the cohomology of the later spaces. In this talk, I will present a method for computing the mod-2 cohomology and obtain a complete description of the cohomology of these spaces in lower orders. A few of the important applications of our work will also be discussed.

  • Speaker: Dr. Navnath Daundkar 
    Affiliation: Post Doctoral Fellow, IIT Bombay
    Date: 28/09/2022
    Title: Moduli spaces of polygonal linkages via cellular surgery

  • Speaker: Dr. Mrinal Nandi 
    Affiliation: Assistant Professor, Department of Statistics, West Bengal State University
    Date: 21/09/2022
    Title: Some Applications of Algebra and the concept of Symmetry
    Relevant Links: [Boardwork] [Video]

  • Speaker: Dr. Avisek Gupta
    Affiliation: Post Doctoral Fellow, IAI – TCG CREST
    Date: 10/08/2022
    Title: Machine Learning under Weak Supervision: Reducing the cost of labelling data
    Relevant Links: [Slides] [Video]

  • Speaker: Dr. Rahul Gangopadhyay
    Affiliation: Post Doctoral Fellow, EIMI and SPbU, Saint Petersburg.
    Date: 27/07/2022
    Title: Crossings in Geometric Hypergraphs
    Relevant Links: [Slides]  [Video]

  • Speaker: Dr. Aranya Lahiri
    Affiliation: SEW Visiting Assistant Professor at UC San Diego
    Date: 06/07/2022
    Title: Irreducibility of rigid analytic vectors in p-adic principal series representations.
    Relevant Links: [Video]

  • Speaker: Dr. Benjamin Wesolowski
    Affiliation: CNRS researcher (Chargé de Recherche), Institut de Mathématiques de Bordeaux (IMB), France
    Date: 22/06/2022
    Title: Hard Problems for Isogeny-based Cryptography

  • Speaker: Dr. Tanmay Basu
    Affiliation: Assistant Professor, IISER Bhopal
    Date: 15/06/2022
    Topic: Role of NLP for Information Extraction from Unstructured Biomedical Text

  • Speaker: Daniel Vallieres
    Affiliation: Assistant Professor, California State University Chico
    Date: 01/06/2022
    Title: Iwasawa theory and graph theory
    Relevant Links: [Video]

  • Speaker: Dr. Luca De Feo
    Affiliation: Research Staff Member, IBM Research Europe
    Date: 25/05/2022
    Title: Isogeny graphs for cryptography
    Relevant Links: [Abstract][Slides][Video]
  • Speaker: Prof. Steven Galbraith
    Affiliation: Head, Mathematics Department, Cyber Security Foundry, University of Auckland
    Date: 18/05/2022
    Title:  Isogeny based cryptography and zero-knowledge proofs of isogeny
    Relevant Links: [Abstract] [Video]

  • Speaker: Mr. Cédric Dion 
    Affiliation: Ph.D. student at Université Laval
    Date: 11/05/2022
    Title: Arithmetic statistics for 2-bridge links
    Relevant Links: [Abstract] [Video]

  • Speaker: Dr. Debanjana Kundu
    Affiliation: PIMS Postdoctoral Fellow at UBC, Vancouver
    Date: 04/05/2022
    Title: Introduction to the theory of elliptic curves and Iwasawa theory
    Relevant Links: [Abstract] [Board-Work] [Video]

  • Speaker: Dr Angsuman Das
    Affiliation: Assistant Professor, Presidency University, Kolkata
    Date: 27/04/2022
    Title: Groups and Graphs
    Relevant Link: [Abstract] [Slides] [Video]

  • Speaker: Dr. Apratim Chakraborty
    Affiliation: Post Doctoral Fellow, IAI TCG CREST
    Date: 06/04/2022
    Title: Elsers conjecture and the topology of U-nucleus complex
    Links: [Abstract] [Slides] [Boardwork] [Video]

  • Speaker: Prof. Prasant Mohapatra
    Affiliation: Professor, Vice Chancellor for Research at University of California, Davis (UC Davis)
    Date: 04/04/2022
    Title: Vulnerabilities in Federated Learning Networks
    Links: [Abstract] [Slides] [Video]

  • Speaker: Prof. Avishek Adhikari
    Affiliation: Professor, Head of Mathematics Department, Presidency University
    Date: 17/03/2022
    Title: Practical Attacks on a Class of Secret Image Sharing Schemes: Few Open Issues
    Links: [Abstract] [Slides] [Board-work] [Video]

  • Speaker: Dr. Angshul Majumdar
    Affiliation: Associate Professor, IIIT Delhi
    Date: 16/03/2022
    Title: Deep Learning based Clustering
    Links: [Abstract] [Slides] [Video]

  • Speaker: Dr. Debolina Ghatak
    Affiliation: Post-Doctoral Fellow at IAI, TCG CREST
    Date: 09/03/2022
    Title: Inference from Private Microdata 
    Links: [Abstract] [Slides] [Video]

  • Speaker: Mr. Arka Banerjee
    Affiliation: Final year Ph.D. student at the University of Wisconsin-Milwaukee 
    Date: 02/03/2022
    Title: Obstruction to coarse embedding
    Links: [Abstract] [Board-Work] [Video]

  • Speaker: Dr. Avik Chakraborti
    Affiliation: Lecturer in Computer Science (E&R), University of Exeter.
    Date: 23/02/2022
    Title: A Brief Introduction to White-box Cryptography
    Links: [Abstract] [Slides] [Video]

  • Speaker: Dr. Ruhul Amin
    Affiliation: Assistant Professor, Computer and Information Sciences Department, Fordham University 
    Date: 16/02/2022
    Title: Homology Based Sequence Annotation Algorithms
    Links: [Abstract] [Slides] [Video]


  • Speaker: Bibhas Chandra Das
    Affiliation: Research Scholar, IAI – TCG CREST
    Date: 09/02/2021
    Title: Dynamic Symmetric Searchable Encryption for Conjunctive Queries
    Links: [Abstract] [Slides] [Video]

  • Speaker: Dr. Dipayan Das
    Affiliation: Post Doctoral Fellow, CISPA-Helmholtz Center for Information Security
    Date: 29th December 2021
    Title: Digital Signatures from ID scheme: Lattice Challenges & Open Problems
    Links: [Abstract] [Slide] [Video]

  • Speaker: Dr. Satrajit Ghosh
    Affiliation: Assistant Professor, IIT Kharagpur
    Date: 22nd December 2021
    Title: In search for sub-linear PSI protocols
    Links: [Abstract] [Board-Work] [Video]

  • Speaker: Mr. Anirban Sanyal
    Affiliation: Department of Economics, UCSC
    Date: 17th December 2021
    Title: Forecasting with Real Time Information
    Links: [Slides]

  • Speaker: Dr. Kuldeep Saha
    Affiliation: Post Doctoral Fellow, IAI TCG CREST, Kolkata
    Date: 08th December 2021
    Title: Persistent Homolgy and Data Analysis
    Links: [Slides] [Video]

  • Speaker: Prof. Mridul Nandi
    Affiliation: Professor, Indian Statistical Institute, Kolkata
    Date: 01st December 2021
    Title: Some Indifferentiable Attacks on Cryptographic Designs
    Links: [Abstract] [Board-work] [Video]


  • Speaker: Dr. Kaushik Chakraborty
    Affiliation: Senior Research Associate, University of Edinburgh, UK
    Date: 24th November 2021
    Title: How to Secure your Cryptosystem with Key-Recycling even if P=NP
    Links: [Slides] [Video]

  • Speaker: Dr. Payel Sadhukhan
    Affiliation: Post Doctoral Fellow, IAI, TCG CREST
    Date: 17th November 2021
    Title of the talk: Open set classification – when you predict more than what you learn
    Links: [Slides] [Video]

  • Speaker: Prof. Samiran Chattopadhyay
    Affiliation: Professor, IAI, TCG CREST
    Date: 10th November 2021
    Title of the talk: A Learning Experience in Performance Improvement of High Throughput Wireless Access Networks
    Links: [Slides] [Video]

  • Speaker: Mr. Arijit Shaw
    Affiliation: Junior Research Fellow, IAI, TCG CREST
    Date: 22nd October 2021
    Title of the talk: CrystallBall: Gazing in the Black Box of SAT Solving
    Links: [Slides] [Video] [Abstract]

  • Speaker: Prof. Rana Barua
    Affiliation: Visiting Scientist, IAI, TCG CREST
    Date: 22nd September 2021
    Title of the talk: On the equation $RX^2+SY^2\equiv 1\bmod N$ and its application to Cryptography
    Abstract: We shall look at attempts at solving the congruence and how it has been used in constructing certain cryptographic primitives.

  • Speaker: Prof. Utpal Chattopadhyay
    Affiliation: Professor at Indian Statistical Institute, Bangalore
    Date: 15th September 2021
    Title of the talk: Quantum Mechanics- Looking back after 100 years
    Links: [Abstract] [Video]

  • Speaker: Dr. Prasenjit Majumder
    Affiliation: Professor at DAIICT, Gandhinagar and Visiting Scientist at IAI, TCG-CREST.
    Date: 8th September 2021
    Title of the talk: Natural Language Processing: Miles to go
    Links: [Abstract] [Slides] [Video]
  • Speaker: Dr. Avijit Dutta
    Affiliation: Post-doctoral Scholar at IAI, TCG-CREST
    Date: 25th August, 2021
    Title of the talk: A Brief Introduction to Zero-Knowlege Proofs
    Links: [Slides] [Video]

  • Speaker: Prof. Bimal Kumar Roy (Inauguration talk)
    Affiliation: Professor at ISI, Honorary Chairman at IAI, TCG-CREST
    Date: 18th August 2021.
    Title of the talk: Some Interesting Ongoing Research Problems in Cryptology, Artificial Intelligence and Machine Learning, and Mathematics.