Nathan Manohar

I am a Research Scientist in Cryptography, Security, and Privacy and a member of the Cryptography Research Group at the IBM T.J. Watson Research Center. My main research interests are cryptography, computer security, and, more broadly, theoretical computer science. I am particularly interested in fully homomorphic encryption, secure multi-party computation, and functional encryption.

I received my PhD in Computer Science from UCLA in December 2021, where I was very fortunate to be advised by Amit Sahai. Previously, I received a bachelor's degree in Computer Science and Mathematics and a master's degree in Computer Science from Harvard in 2016.

Email: n lastname [at] ibm [dot] com

Publications

• On the Hardness of Scheme-Switching Between SIMD FHE Schemes
  Karim Eldefrawy, Nicholas Genise, Nathan Manohar
  PQCrypto 2023
• Implementation of a Hardware-Assisted Bluetooth-Based COVID-19 Tracking Device in a High School: Mixed Methods Study
  Dan Li, Tyler Shelby, Marie Brault, Rajit Manohar, Sten Vermund, Ashley Hagaman, Laura Forastiere, Tyler Caruthers, Emilie Egger, Yizhou Wang, Nathan Manohar, Peter Manohar, J Lucian Davis, Xin Zhou
  JMIR Formative Research 2023
• CraterLake: A Hardware Accelerator for Efficient Unbounded Computation on Encrypted Data
  Nikola Samardzic, Axel Feldmann, Aleksandar Krastev, Nathan Manohar, Nicholas Genise, Srinivas Devadas, Karim Eldefrawy, Chris Peikert, Daniel Sanchez
  ISCA 2022
• Sine Series Approximation of the Mod Function for Bootstrapping of Approximate HE
  Charanjit S. Jutla, Nathan Manohar
  EUROCRYPT 2022
• Secure MPC: Laziness Leads to GOD
  Saikrishna Badrinarayanan, Aayush Jain, Nathan Manohar, Amit Sahai
  ASIACRYPT 2020
• Amplifying the Security of Functional Encryption, Unconditionally
  Aayush Jain, Alexis Korb, Nathan Manohar, Amit Sahai
  CRYPTO 2020
• Self-Processing Private Sensor Data via Garbled Encryption
  Nathan Manohar, Abhishek Jain, Amit Sahai
  PETS 2020
• Combiners for Functional Encryption, Unconditionally
  Aayush Jain, Nathan Manohar, Amit Sahai
  EUROCRYPT 2020
• From FE Combiners to Secure MPC and Back
  Prabhanjan Ananth, Saikrishna Badrinarayanan, Aayush Jain, Nathan Manohar, Amit Sahai
  TCC 2019
• Watermarking Public-Key Cryptographic Primitives
  Rishab Goyal, Sam Kim, Nathan Manohar, Brent Waters, David J. Wu
  CRYPTO 2019
• T/Key: Second-Factor Authentication From Secure Hash Chains
  Dmitry Kogan, Nathan Manohar, Dan Boneh
  CCS 2017

Manuscripts

• Modular Lagrange Interpolation of the Mod Function for Bootstrapping of Approximate HE
  Charanjit S. Jutla, Nathan Manohar
• HABIT: Hardware-Assisted Bluetooth-based Infection Tracking
  Nathan Manohar, Peter Manohar, Rajit Manohar
  Deployed at high schools in Connecticut in collaboration with the Yale School of Public Health.

Theses

• High Precision Bootstrapping of Approximate Homomorphic Encryption
  PhD Thesis (2021)
  
• Hardness of Lattice Problems for Use in Cryptography
  Undergraduate Thesis (2016)
  

Interns

I have been fortunate to work with the following interns.

• Akash Shah (Summer 2022, PhD Student at UCLA)
• Julia Guskind (Summer 2022, Undergraduate Student at UConn)

Professional Service

I have served on the organizing committee of the following workshops.

• DISCC 2022: 1st Workshop on Data Integrity and Secure Cloud Computing

I have served as an external reviewer for various editions of the following conferences/journals.

• CRYPTO, EUROCRYPT, ASIACRYPT, TCC, PKC, CCC, ITCS, SCN, ICALP, ITC, Designs, Codes, and Cryptography

Personal

In my spare time, I enjoy playing violin and piano. I currently play violin in The Broadway Bach Ensemble, and, as a PhD student, I played violin in the UCLA Symphony. I also like to spend time with my cat, Mary, who shares similar interests.