I am an Associate Professor in the Department of Computer Science at NUS, and a Principal Investigaror at CQT. Before joining NUS/CQT, I was a post-doctoral researcher for two years each in the School of Computer and Communication Sciences at EPFL, and the Department of Computer Science at New York University. I completed my PhD under the guidance of Prof. Ueli Maurer at ETH Zurich in February, 2012. 

Research Interests:

Broadly speaking, I am interested in discrete structures and their applications in theoretical computer science. In particular, I am interested in the following:

•  Information-theoretic Cryptography

•  Randomness Extractors and Applications

•  Lattices in Computer Science

•  Coding Theory

•  Computational number theory

Cryptographers think of me  as a theorist, and theorists think of me as a cryptographer. I like to think of myself as a theorist. Perhaps that makes me a cryptographer :)

Open positions:

I am looking for highly motivated PhD students and postdocs interested in all aspects of computational complexity, discrete mathematics, and algorithms. If you are interested, send me an email.

I am always happy to host very strong PhD students for a 2-3 month internship. If you are interested, please write to me. I typically don't invite undergraduate students for an internship unless you are interested in a PhD position at NUS in the near future. 

Link to our group research seminar

Group Members (present and past):

• Graduate Students:
  Eldon Chung, 2020-present
  Zeyong Li, 2020-present
  
  

• Postdoc:

Pranjal  Datta,  2023-present

• Senior Research fellow:
  Maciej Obremski, 2018-present
  
  
  

• Regular visitors:

Alexander  Golovnev
Noah Stephens-Davidowitz
Siyao Guo

• Alumni:

Erick Purwanto, PhD student, 2016-2019   -->   Teaching fellow,  XJTLU
Priyanka Mukhopadhyay, PhD student, 2016-2018  -->  postdoc, UToronto
Rajendra Kumar: PhD student and postdoc, 2019-2022  --> postdoc, Weizmann Institute.
Jianwei Li: Postdoc, 2018-2019  

Publications:

1.  Unforgeability in Stochastic Gradient Descent. [link]

Teodora Baluta, Ivica Nikolikj, Racchit Jain, Divesh Aggarwal and Prateek Saxena.
ACM CCS 2023. 

2. Why we couldn't prove SETH hardness of the Closest Vector Problem for even norms! [link]
   Divesh Aggarwal and Rajendra Kumar.
   FOCS 2023.

3. Engineering an Efficient Approximate DNF-Counter. [link]
   Mate Soos,  Divesh Aggarwal,  Sourav  Chakraborty, Kuldeep S. Meel, Maciej Obremski.
   IJCAI 2023.

4. Extractors: Low Entropy Requirements Colliding with Non-malleability. [link]
   Divesh Aggarwal, Eldon Chung, Maciej Obremski.
   CRYPTO 2023. 

5. Lattice Problems Beyond Polynomial Time. [link]
   Divesh Aggarwal, Huck Bennett, Zvika Brakerski, Alexander Golovnev, Rajendra Kumar, Zeyong Li, Spencer Peters, Noah Stephens-Davidowitz, Vinod Vaikuntanathan.
   STOC 2023.

6. Quantum Secure Non-malleable codes in the split-state model. [link]
   Divesh Aggarwal, Naresh Goud Boddu, Rahul Jain.
   In IEEE Transactions of Information Theory, 2023.

7. Quantum Measurement Adversary. [link]
   Divesh Aggarwal, Naresh Boddu, Rahul Jain, and Maciej Obremski.
   IEEE Transactions of Information Theory, 2023. 

8. Survey: Non-malleable codes in the split-state model. [link]
   Divesh Aggarwal, Marshall Ball, Maciej Obremski.
   Entropy 2022.

9. On Secret Sharing, Randomness, and Random-less Reductions for Secret Sharing. [link]
   Divesh Aggarwal, Eldon Chung, Maciej Obremski, and Joao Ribeiro.
   TCC 2022.

10. Privacy Amplification with Tamperable Memory via Non-malleable Two-source Extractors. [link]
    Divesh Aggarwal, Maciej Obremski, Joao Ribeiro, Mark Simkin, and Luisa Siniscalchi.
    In IEEE Transactions on Information Theory, 2022.

11. Rate One-Third Non-Malleable Codes. [link]
    Divesh Aggarwal, Bhavana Kanukurthi, Sai Lakshmi Bhavana Obbattu, Maciej Obremski, Sruthi Sekar.
    STOC 2022.

12. Algebraic Restriction Codes and their Applications. [link]
    Divesh Aggarwal, Nico Dottling, Jesko Dujmovic, Mohammad Hajiabadi, Giulio Malavolta, Maciej Obremski.
    In ITCS 2022.

13. An Improved Time-Approximation Factor tradeoff for (H)SVP. [link]
    Divesh Aggarwal, Zeyong Li, Noah Stephens-Davidowitz.
    In EUROCRYPT 2021.

14. Improved Classical and Quantum Algorithms for the Shortest Vector Problem via Bounded Distance Decoding. [link]
    Divesh Aggarwal, Yanlin Chen, Rajendra Kumar, Yixin Shen.
    In STACS 2021, QIP 2022.

15. A Note on the Concrete Hardness of the Shortest Independent Vectors Problem in Lattices. [link]
    Divesh Aggarwal, Eldon Chung.
    In Information Processing Letters 2021.

16. Dimension preserving reductions between SVP and CVP in Different p-Norms. [link]
    Divesh Aggarwal, Yanlin Chen, Rajendra Kumar, Zeyong Li, Noah Stephens-Davidowitz.
    In SODA 2021.

17. Fine-grained hardness of CVP(P)– Everything that we can prove (and nothing else). [link]
    Divesh Aggarwal, Huck Bennett, Alexander Golovnev, Noah Stephens-Davidowitz.
    In SODA 2021.

18. A constant rate non-malleable code in the split-state model. [link]
    Divesh Aggarwal, Maciej Obremski.
    In FOCS 2020.

19. Extractor Lower Bounds, Revisited. [link]
    Divesh Aggarwal, Siyao Guo, Maciej Obremski, Joao Ribeiro, Noah Stephens-Davidowitz.
    In RANDOM 2020.

20. Slide reduction, revisited–Filling the gaps in SVP approximation. [link]
    Divesh Aggarwal, Jianwei Li, Phong Nguyen, Noah Stephens-Davidowitz.
    In CRYPTO 2020.

21. How to extract useful randomness from unreliable sources. [link]
    Divesh Aggarwal, Maciej Obremski, Joao Ribeiro, Luisa Siniscalchi, Ivan Visconti.
    In EUROCRYPT 2020.

22. An improved constant in Banaszczyk’s transference theorem. [link]
    Divesh Aggarwal and Noah Stephens-Davidowitz.
    Manuscript.

23. Stronger Leakage-Resilient and Non-Malleable Secret-Sharing Schemes for General Access Structures.[link]
    Divesh Aggarwal, Ivan Damgard, Jesper Buus Nielsen, Maciej Obremski, Erick Purwanto, Joao Ribeiro, and Mark Simkin.
    CRYPTO 2019.

24. Continuous Non-Malleable Codes in the 8-Split State Model. [link]
    Divesh Aggarwal, Nico Dottling, Jesper Buus Nielsen, Maciej Obremski, and Erick Purwanto.
    EUROCRYPT 2019.

25. A Quantum-Proof Non-Malleable Extractor, With Application to Privacy Amplification against Quantum Adversaries. [link]
    Divesh Aggarwal, Kai-Min Chung, Han-Hsuan Lin, and Thomas Vidick.
    EUROCRYPT 2019.

26. A New Public-Key Cryptosystem via Mersenne Numbers. [link]
    Divesh Aggarwal, Antoine Joux, Anupam Parkash, and Miklos Santha.
    CRYPTO 2018.

27. Faster Algorithms for SVP and (Approx)-CVP in the Infinity Norm. [link]
    Divesh Aggarwal and Priyanka Mukhopadhyay.
    ISAAC 2018.

28. Quantum Attacks on Bitcoin, and How to Protect Against Them. [link]
    Divesh Aggarwal, Gavin K. Brennen, Troy Lee, Miklos Santha, and Marco Tomamichel.
    Ledger 2018.

29. Leakage-resilient Algebraic Manipulation Detection Codes with Optimal Parameters. [link]
    Divesh Aggarwal, Tomasz Kazana, and Maciej Obremski.
    ISIT 2018.

30. (Gap/S)ETH Hardness of SVP. [link]
    Divesh Aggarwal and Noah Stephens-Davidowitz.
    STOC 2018.

31. Just Take the Average! An Embarrassingly Simple 2^n-Time Algorithm for SVP (and CVP) [link]
    Divesh Aggarwal and Noah Stephens-Davidowitz.
    SOSA 2018.

32. Inception makes non-malleable codes stronger [link]
    Divesh Aggarwal, Tomasz Kazana, and Maciej Obremski.
    TCC 2017. 

33. A note on discrete Gaussian combinations of lattice vectors [link]
    Divesh Aggarwal and Oded Regev. 
    In Chicago Journal of Theoretical Computer Science, 2016. 

34. Improved hardness results for unique shortest vector problem [link]
    Divesh Aggarwal and Chandan Dubey.
    In Information Processing Letters 2016.

35. Revisiting the Sanders-Bogolyubov-Ruzsa Theorem in F_p^n and its Application to Non-malleable Codes [link]
    Divesh Aggarwal and Jop Briët.
    ISIT 2016.

36. Affine-malleable extractors, spectrum doubling, and application to privacy amplification [link]
    Divesh Aggarwal, Kaave Hosseini, and Shachar Lovett.
    ISIT 2016. 

37. Optimal computational split-state non-malleable codes [link]
    Divesh Aggarwal, Shashank Agrawal, Divya Gupta, Hemanta K. Maji, Omkant Pandey, and Manoj Prabhakaran.
    TCC 2016-A. 

38. Solving the Closest Vector Problem in 2^n Time --- the discrete Gaussian strikes again! [link]
    Divesh Aggarwal, Daniel Dadush, and Noah Stephens-Davidowitz.
    FOCS 2015. 

39. A Note on lower bounds for non-interactive message authentication using weak keys [link]
    Divesh Aggarwal and Alexander Golovnev.
    ITW 2015. 

40. Solving the Shortest Vector Problem in 2^n time via discrete Gaussian sampling [link]
    Divesh Aggarwal, Daniel Dadush, Oded Regev, and Noah Stephens-Davidowitz.
    STOC 2015. 

41. Non-malleable reductions and applications [link]
    Divesh Aggarwal, Yevgeniy Dodis, Tomasz Kazana, and Maciej Obremski. STOC 2015. 

42. Leakage-resilient non-malleable codes [link]
    Divesh Aggarwal, Stefan Dziembowski, Tomasz Kazana, and Maciej Obremski.
    TCC 2015.  

43. Affine-evasive sets modulo a prime [link]
    Divesh Aggarwal.
    Information Processing Letters 2015.

44. Amplifying privacy in privacy amplification [link]
    Divesh Aggarwal, Yevgeniy Dodis, Zahra Jafargholi, Eric Miles, and Leonid Reyzin.
    CRYPTO 2014. 

45. Non-malleable codes from additive combinatorics [link]
    Divesh Aggarwal, Yevgeniy Dodis, and Shachar Lovett.
    STOC 2014; Journal version: Siam Journal of Computing, 2018.

46. The leakage-resilience limit of a computational problem is equal to its unpredictability entropy [link]
    Divesh Aggarwal and Ueli Maurer.
    ASIACRYPT 2011. 

47. The equivalence of strong RSA and factoring in the generic ring model of computation [link]
    Divesh Aggarwal, Ueli Maurer, and Igor Shparlinski.
    WCC 2011. 

48. Breaking RSA generically is equivalent to factoring  [link]
    Divesh Aggarwal and Ueli Maurer.
    EUROCRYPT 2009; Journal version: IEEE Transactions on Information Theory, 2017.

49. Algorithms on graphs with small dominating targets [link]
    Divesh Aggarwal, Chandan Dubey, and Shashank K. Mehta.
    ISAAC 2006. 

50. Domination search on graphs with low dominating-target-number [link]
    Divesh Aggarwal, Shashank Mehta, and Jitender Deogun.
    WG 2005.
    
    
    

Teaching:

Instructor:

• Computational Complexity                      Sem 2, 2017-18, 2018-19  

• Introduction to Information Theory         Sem 2, 2016-17, 2021-22

• Pseudorandomness                                        Sem 1, 2018-19

• Design and Analysis of Algorithms       Sem 1, Sem 4, 2019-20, Sem 1, 2020-21

Professional Activities:

Program Committee: TCC 2016-B, SCN 2016, ICITS 2016, ICITS 2017, TCC 2018, SPACE 2018, Indocrypt 2019, NuTMIC 2019, Eurocrypt 2020, SCN 2020, ITC 2021, CRYPTO 2021, ANTS 2022, Asiacrypt 2022, FSTTCS 2022.

Editorial Board: Information Processing Letters (February 2021-present)

Organizing Committee: TCC 2010, AQIS 2018. 

Contact Information: 

   1. Centre of Quantum Technologies

       S15 #04-12

       National University of Singapore

       Block S15, 3 Science Drive 2

       Singapore 117543

   2. School of Computing

       COM3 #02-09

       11 Research Link

       Singapore 119391 

   Phone:   +65 6516 5628 (office)

               +65 6516 2911 (office)

   Email:   divesh@comp.nus.edu.sg

                divesh.aggarwal@gmail.com