Current position

Visiting Lecturer (since May 2017)
R C Bose Centre for Cryptology and Security
Indian Statistical Institute, Kolkata

Reach me at

EMail     (preferred mode)
Phone   +91 94323 44852     (only if urgent please)
Office   Room 404, 3rd Floor, Deshmukh Building

I am teaching

Course   Computing for Data Sciences
Degree   PGDBA -- First Year First Semester
The course website will be active shortly.

About Me about

I am a Researcher, positioned precariously at the confluence of Computer Science, Mathematics and Engineering, and I study the art and science of Cryptology and Information Security.

Academic Positions

Academic Background

I will be glad to share a copy of my CV, with further professional details, if you are interested.

Research research

My research inclination follows two apparently diverse tracks in Cryptology -- mathematical analysis of cryptographic primitives towards discovering practically exploitable vulnerabilities, and efficient engineering of cryptographic designs for high performance in practice.

In Cryptanalysis, my interests range across theoretical problems like statistical analysis of stream ciphers to lattice-based attacks on RSA and factorization. I also take active interest in applications of Cryptology in visual cryptographic schemes, key pre-distribution and electronic cash. The central theme of my research has always targeted at bridging the gap between theory and practice in Cryptology.

In addition to my primary interests in Cryptology, I am also inclined towards research topics in Number Theory that have close ties with cryptographic applications. Distribution of primes, primality testing algorithms, the factorization problem, lattice based analysis of cryptographic constructions, and topics in elliptic curve cryptography pique my interest. Time and again, I also like to explore elegant theoretical and computational problems in elementary Number Theory.

Teaching teaching

Computer Science

Since Fall 2014, I have taught the following courses at Indian Statistical Institute, Kolkata. Please feel free to browse through the course websites to know more about the course format and contents.

Publications publications

The following is a select list of my publications. Please feel free to check my DBLP page as well.
I will be glad to share a copy of my CV, with a complete list of publications, if you are interested.

Refereed Journal

  • Proving TLS-attack related open biases of RC4
      Des. Codes Cryptography 77(1): 231-253 (2015) -- S. Sarkar, S. Sen Gupta, G. Paul, S. Maitra
  • (Non-)Random Sequences from (Non-)Random Permutations -- Analysis of RC4 stream cipher
      Journal of Cryptology 27(1): 67-108 (2014) -- S. Sen Gupta, S. Maitra, G. Paul, S. Sarkar
  • High Performance Hardware Implementation for RC4 Stream Cipher
      IEEE Trans. Computers 62(4): 730-743 (2013) -- S. Sen Gupta, A. Chattopadhyay, K. Sinha, S. Maitra, B. P. Sinha
  • Designing Integrated Accelerator for Stream Ciphers with Structural Similarities
      Cryptography and Communications 5(1): 19-47 (2013) -- S. Sen Gupta, A. Chattopadhyay, A. Khalid
  • Counting Heron triangles with constraints
      INTEGERS 13: #A3 (2013) -- P. Stanica, S. Sarkar, S. Sen Gupta, S. Maitra, N. Kar

Refereed Conference

  • Dependence in IV-related bytes of RC4 key enhances vulnerabilities in WPA
      FSE 2014 -- S. Sen Gupta, S. Maitra, W. Meier, G. Paul and S. Sarkar
  • Attack on Broadcast RC4 Revisited
      FSE 2011 -- S. Maitra, G. Paul and S. Sen Gupta
  • Proof of Empirical RC4 Biases and New Key Correlations
      SAC 2011 -- S. Sen Gupta, S. Maitra, G. Paul and S. Sarkar
  • HiPAcc-LTE: An Integrated High Performance Accelerator for 3GPP LTE Stream Ciphers
      INDOCRYPT 2011 -- S. Sen Gupta, A. Chattopadhyay and A. Khalid
  • One Byte per Clock: A Novel RC4 Hardware
      INDOCRYPT 2010 -- S. Sen Gupta, K. Sinha, S. Maitra and B. P. Sinha
  • Partial Key Exposure Attack on RSA - Improvements for Limited Lattice Dimensions
      INDOCRYPT 2010 -- S. Sarkar, S. Sen Gupta and S. Maitra
  • Factoring RSA Modulus using Prime Reconstruction from Random Known Bits
      AFRICACRYPT 2010 -- S. Maitra, S. Sarkar and S. Sen Gupta


  • Analysis and Implementation of RC4 Stream Cipher
      PhD Thesis (2013) -- Advisor: Prof. Subhamoy Maitra, ISI Kolkata
  • Artin's Conjecture - Unconditional Approach and Elliptic Analogue
      MMath Thesis (2008) -- Advisor: Dr. Yu-Ru Liu and Dr. Wentang Kuo, Univ. of Waterloo

Synergy synergy

  • Member of Program Committee - Indocrypt 2016, Indocrypt 2015, Indocrypt 2014
  • Reviewer/Sub-reviewer for Journal of Cryptology, IEEE Trans. on Computers, CCDS, Crypto, Eurocrypt, Asiacrypt, FSE, SAC, Indocrypt, Africacrypt, ProvSec, etc.
  • Member of Organizing Committee for Indocrypt 2012, Indocrypt 2013 and VLSI Design 2016.
  • Organized several workshops and training programs in Cryptology and allied disciplines, hosted by Centre of Excellence in Cryptology, Indian Statistical Institute, Kolkata.
  • Organized several summer internships and training programs in Cryptology and allied disciplines, hosted by R C Bose Centre for Cryptology and Security, Indian Statistical Institute, Kolkata.
  • Organized several Mathematics workshops and training programs for school students, primarily targeted towards Mathematics Olympiad. Affiliated with the RMO Committee of West Bengal.
  • Co-organizer of various workshops and training programs in Free and Open Source Software.



Sourav's Photo

Member of

  • IACR [2012-13, 2014-15]
  • CRSI [Life Member]
  • AMS [2006-07, 2008-09]

You may like


I have had a bounty of hobbies and leisurely activities over the course of time -- sketching, magic, shayaari, recitation, karate, and many more. At present, I am interested in cooking, photography, web development, and free and open-source software movement.

I am also an avid reader, and I love listening to technical and non-technical lectures from various sources (TED talks are my favorite).