**Introduction to Secret Sharing.**

Advanced Training in Mathematics Workshop (ATMW) on Cryptology (April 10-14, 2018), Indian Statistical Institute (ISI), Kolkata, India, sponsored by National Centre for Mathematics (a joint centre of IIT Bombay and TIFR, Mumbai), April 11, 2018.**Introduction to Randomness, Numbers and Cryptography.**

Scholastic Test of Excellence in Mathematical Sciences (STEMS) Camp (February 9-11, 2018), Chennai Mathematical Institute, Chennai, India, February 10, 2018.**Design and Analysis of Encryption Algorithms.**

Workshop on Some Theoretical Aspects in Computing and Applications (January 8-12, 2018), Department of Computer Science and Technology, Indian Institute of Engineering Science and Technology (IIEST), Shibpur, Howrah, India, January 12, 2018.**Cryptographic Security for Communication Network.**

National Conference on Advancement of Security in Modern Communication Network (ACIN), Electronics and Communication Engineering Department, Dr. Sudhir Chandra Sur Degree Engineering College, Kolkata, India, October 27, 2017.**Cryptography: a saga of reincarnation!**

Annual Technical Fest – DAKSHH, Heritage Institute of Technology, Kolkata, India, March 20, 2017.**Random number generation and its applications.**

Workshop on Mathematics, Computer Science and Cryptology (Jan 30-31, 2017), Bhawanipur Education Society College, Kolkata, India, January 30, 2017.**From Battle-fields to Bank ATMs — the Evolution of Cryptology.**

Seminar at Bhawanipur Education Society College, Kolkata, India, September 16, 2016.**How Randomness Is Used in Cryptography.**

One-day State-Level Workshop on Mathematics, Computer Science and Cryptology, Department of Mathematics, Computer Science and Science Forum, Mrinalini Datta Mahavidyapith, Birati, Kolkata, India, August 23, 2016.**From Randomness to WiFi Security and Beyond.**

Seminar at Department of Mathematics and Statistics, Himachal Pradesh University, Shimla, India, June 6, 2016.**Some Ores from Crypto-mines.**

Special Research Talk for Summer Internship in Cryptology (May 16 – July 15, 2016), Indian Statistical Institute (ISI), Kolkata, India, May 20, 2016.**Introduction to Stream Cipher Security.**

Workshop on Cryptology for North Eastern States (January 21-27, 2016), Applied Statistics Unit (ASU), Indian Statistical Institute (ISI), Kolkata, India, January 27, 2016.**Introduction to Stream Cipher Design.**

Workshop on Cryptology for North Eastern States (January 21-27, 2016), Applied Statistics Unit (ASU), Indian Statistical Institute (ISI), Kolkata, India, January 25, 2016.**Overview of Hardware Cryptography.**

Workshop on Digital Design (Nov 6-8, 2015), Advanced Computing and Microelectronics Unit (ACMU), Indian Statistical Institute (ISI), Kolkata, India, November 6, 2015.**Non-randomness of Reduced-round Salsa20 and Its Implications.**

Workshop on Security of Symmetric Ciphers in Network Protocols (May 25-29, 2015), International Centre for Mathematical Sciences (ICMS), Edinburgh, under EPSRC-DST Indo-UK Initiative in Applied Mathematics, May 28, 2015.**Differential Cryptanalysis of Salsa20.**

Targeted Training Program at Indian Statistical Institute (ISI), Delhi, India, March 20, 2015.**Linear Cryptanalysis of HC-128.**

Targeted Training Program at Indian Statistical Institute (ISI), Delhi, India, March 20, 2015.*An Application of Random Graphs in Cryptanalysis.*

ASU Seminar Series, Applied Statistics Unit (ASU), Indian Statistical Institute (ISI), Kolkata, India, March 3, 2015.*A Short Tour of Symmetric Key Encryption: Stream Ciphers.*

National Level North East Workshop on Cryptology (January 22-24, 2015), C.I. College, Bishnupur, Manipur, India, January 23, 2015.*A Short Tour of Symmetric Key Encryption: Block Ciphers.*

National Level North East Workshop on Cryptology (January 22-24, 2015), C.I. College, Bishnupur, Manipur, India, January 23, 2015.*Statistical Cryptanalysis of RC4 as used in WEP, WPA and TLS: Foundations and Important Results.*

Winter School on Interplay Between Statistics and Cryptology (December 1-5, 2014), organized by Applied Statistics Unit, Indian Statistical Institute, Kolkata, in collaboration with EPSRC-DST Indo-UK Initiative in Applied Mathematics, December 3, 2014.*Number Theoretic Algorithms for Public Key Cryptography.*

Course on Cryptography, Department of Computer Science & Engineering, Tripura Institute of Technology (TIT), Agartala, India, November 8, 2014.**From Insecure Randomness to Secure Pseudo-randomness: A journey with permutation over integers modulo N.**

Colloquium at Department of Computer Science, University at Albany, State University of New York, U.S.A., July 21, 2014.*Permutation, Randomness and WiFi Security.*

Seminar at Department of Computer Science, University of Nevada, Las Vegas, U.S.A.,July 17, 2014*Symmetric Key Cryptography: Stream Ciphers.*

Short Term Course on Cryptography (May 18-24, 2014), Department of Mathematics, Indian Institute Technology (IIT) Kharagpur, India, May 18, 2014.**Introduction to Classical Cryptography.**

Short Term Course on Cryptography (May 18-24, 2014), Department of Mathematics, Indian Institute Technology (IIT) Kharagpur, India, May 18, 2014.*Introduction to Block Ciphers.*

Staff Development Programme on Cryptography & Information Security (Sep 21-25, 2013), Govt. College of Engineering & Textile Technology – Berhampore, Murshidabad, India, Sep 22, 2013.*Introduction to Cryptology.*

Staff Development Programme on Cryptography & Information Security (Sep 21-25, 2013), Govt. College of Engineering & Textile Technology – Berhampore, Murshidabad, India, Sep 21, 2013.*Biases and Distinguishers of the RC4 Stream Cipher.*

Seminar at Crypto and Security group, Department of Electrical and Information Technology, Lund University, Sweden, March 27, 2013.*A Look into (Non-)Randomness of RC4 Stream Cipher.*

Theory Seminar at Center for the Theory of Interactive Computation (CTIC),Aarhus University, Denmark, March 22, 2013.*The RC4 Landscape: Hills, Canyons and Plateaus.*

Seminar at Security and Cryptography Laboratory (LASEC), School of Computer and Communication Sciences (I&C), Ecole Polytechnique Federale de Lausanne (EPFL), Switzerland, February 8, 2013.*Connection between Information Theory and Security.*

Seminar at the Institute for Communication Technologies and Embedded Systems (ICE), Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen, Germany, June 26, 2012.*An Overview of Classical Information and Classical Cryptography.*

Workshop on Information and Security in Quantum World (March 28-30, 2012), Indian Statistical Institute, Kolkata, India, March 28, 2012.*Distinguishing Attacks on Stream Ciphers.*

ASU Seminar Series, Applied Statistics Unit (ASU), Indian Statistical Institute (ISI), Kolkata, India, November 29, 2011.*Trivial and Non-trivial Issues of TRIVIUM.*

Workshop on eSTREAM Ciphers (Sep 30-Oct 1, 2011), Indian Statistical Institute, Delhi Centre, India, September 30, 2011.*Stream Ciphers: from One Time Pad to 4G.*

National Level Workshop on Cryptology (September 29-30, 2011) for College and University Teachers and Students, West Bengal State University, Barasat, India, September 29, 2011.*How to Send Secret Messages in Public.*

NAMSAA Popular Talk Series, New Alipore Multipurpose School, Kolkata, India, September 24, 2011.*Partial State Exposure of HC-128 and Its Consequences.*

Indo-Japan Joint Workshop on Cryptography, Indian Statistical Institute, Kolkata, India, September 15, 2011.*Random Number Generation and Stream Cipher.*

Tutorial Workshop on Cryptology, Rajabazar Science College Campus, University of Calcutta, India; jointly organized by the University of Calcutta & the Centre of Excellence in Cryptology, Indian Statistical Institute, July 16, 2011.*Wireless Encryption Algorithms.*

UGC Refresher Course for College and University Teachers on Security in Wired and Wireless Networks, School of Mobile Computing and Communication, Jadavpur University, Kolkata, India, July 14, 2011.*Randomness and Cryptography.*

Seminar organized by Computer Chapter of IEEE Calcutta Section, School of Mobile Computing and Communication, Jadavpur University, Kolkata, India, July 13, 2011.*Cryptology: The Art and Science of Secure Communication.*

Workshop on Emerging Technology in Computing, June 8, 2011, St. Thomas’ College of Engineering & Technology, Kolkata, India.*Fundamentals of Stream Ciphers.*

National Level Instructional Workshop on Cryptology (May 9-13, 2011), Centre for Cyber Security, Amrita Vishya Vidyapeetham, Coimbatore, India, May 11, 2011.*Cryptosystems and Cryptanalytic Attacks.*

Training on Information and Network Security, Scientific Analysis Group (SAG), Defence Research & Development Organisation (DRDO), Delhi, Ministry of Defence, Govt. of India, February 4, 2011.*Symmetric Key Cryptography: Some Modern Stream Ciphers.*

BARC Lecture Series on Cryptology, Supercomputing Facility, Computer Division, Bhabha Atomic Research Centre (BARC), Mumbai, India, November 23, 2010.*State of the Art Software Stream Ciphers.*

National Level Instructional Workshop on Cryptology (for University and College Teachers of the North-East Region, May 5-7, 2010), Department of Mathematics, Manipur University, Imphal, India, May 6, 2010..**Construction of Full State from Half State of HC-128**

Seminar at Coding & Cryptography Research Group (CCRG), Division of Mathematical Sciences, School of Physical & Mathematical Sciences, Nanyang Technological University (NTU), Singapore, March 10, 2010.*New Distinguishing Attacks on HC-128.*

Security Fundamentals (SF) Meeting, Research Center for Information Security (RCIS), National Institute of Advanced Industrial Science and Technology (AIST), Akihabara Site, Tokyo, Japan, July 13, 2009.*Stream Cipher RC4: A Case Study.*

Workshop on Teaching Cryptology at Undergraduate Level, Indian Statistical Institute (ISI), Kolkata, India; jointly organized by the Cryptology Research Society of India (CRSI) and the Institute of Mathematical Sciences (IMSc), Chennai, India; partially sponsored by Department of Science and Technology (DST), Government of India, June 18, 2009.*Recent Advances in RC4 Cryptanalysis.*

Workshop on Cryptography, Institute of Mathematics and Applications (IMA), Bhubaneswar; co-organized by the National Institute of Science Education and Research (NISER), Bhubaneswar (an Autonomous Institution of Department of Atomic Energy, Government of India); sponsored by the Science and Technology Department, State Council on Science and Technology, Government of Orissa and Institute of Mathematical Sciences (IMSc), Chennai, India, December 6, 2008.*Cryptology: A Technical Overview.*

Seminar at TwoPiRadian Infotech Private Limited (http://www.2pirad.com), Kolkata, India, February 2, 2008.**On New Weaknesses of the RC4 Stream Cipher**.

Centre for Applied Cryptographic Research (CACR) Seminar Series, University of Waterloo, Ontario, Canada, August 22, 2007.*Structural Weakness of the Key Scheduling of RC4.*

1st Indo-French Workshop on Cryptography and Related Topics (IFW), Paris, France, organized by the Indo-French Centre for the Promotion of Advanced Research under the Department of Science and Technology (DST), Government of India and the Ministry of Foreign Affairs, Government of France, June 11, 2007.*Basics of Public Key Cryptography.*

State Level Seminar on Application of Cryptology in Industry and Cryptanalysis (ACIC), Science City, Kolkata, India, organized by the Department of Information Technology of the RCC Institute of Information Technology and Partially Sponsored by Cognizant Technology Solutions (CTS), May 5, 2007.