Mahesh Sreekumar Rajasree

CISPA Helmholtz Center for Information Security, Sankt Ingbert, Germany

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I am currently a Postdoctoral Researcher at CISPA Helmholtz Center for Information Security, hosted by Prof. Nico Döttling. My research focuses on public-key cryptography and quantum cryptography.

Previously, I was a Postdoctoral Fellow in the Department of Computer Science and Engineering, Indian Institute of Technology Delhi, where I worked under the guidance of Prof. Venkata Koppula.

I completed my PhD (as a Prime Minister’s Research Fellow) and MTech degree under the guidance of Prof. Manindra Agrawal in the Department of Computer Science and Engineering, Indian Institute of Technology, Kanpur. During that time, I was actively working on the cryptanalysis of symmetric-key cryptosystems and variants of the subset-sum problem.

My Erdős number is 3 (Me -> Antoine Joux -> Andrew M. Odlyzko -> Paul Erdős).

News

Jul 3, 2026 “Pigeonhole Equal Subset Sum: Subexponential Algorithm, Tight Lower Bounds and Average-Case Analysis” accepted at FOCS 2026!
Jun 1, 2026 Research visit to Charles III University of Madrid, Leganés Campus, Madrid, Spain, hosted by Prof. Lorena González-Manzano.
May 25, 2026 Research visit and talk at IMDEA Software Institute, Madrid, Spain, hosted by Prof. Dario Fiore.
May 5, 2026 “Chosen Ciphertext Secure Pseudorandom Codes in the Standard Model” accepted at CRYPTO 2026!
Mar 31, 2026 Research visit to Faculty of Mathematics, Informatics, and Mechanics, University of Warsaw, Poland.

Selected Publications

  1. Pigeonhole Equal Subset Sum: Subexponential Algorithm, Tight Lower Bounds and Average-Case Analysis
    Deepak Bhati, Pranjal DuttaAntoine Joux, and 2 more authors
    In Foundations of Computer Science - FOCS, 2026
  2. Chosen Ciphertext Secure Pseudorandom Codes in the Standard Model
    Nico DöttlingAntoine JouxVenkata Koppula, and 2 more authors
    In Advances in Cryptology - CRYPTO, 2026
  3. Separating Pseudorandom Codes from Local Oracles
    Nico DöttlingAnne Müller, and Mahesh Sreekumar Rajasree
    In Theory of Cryptography - TCC, 2025
    Outstanding Paper Award
  4. A Note on Adaptive Security in Hierarchical Identity-Based Encryption
    Rishab GoyalVenkata Koppula, and Mahesh Sreekumar Rajasree
    In Advances in Cryptology - CRYPTO, 2025
  5. Incompressible Functional Encryption
    Rishab GoyalVenkata KoppulaMahesh Sreekumar Rajasree, and 1 more author
    In Innovations in Theoretical Computer Science - ITCS, 2025