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Publications

2026

• Osprey: Transparent and Efficient Virtual Memory for Secure Computation.
  Yicheng Liu, Alice Yeh, Harry Xu, Raluca Ada Popa, and Sam Kumar.
  20th USENIX Symposium on Operating Systems Design and Implementation (OSDI 2026).

• Efficient ML Model Updates for Deeply Embedded Microcontrollers.
  Shishir G. Patil, Sam Kumar, Prabal Dutta, and Joseph E. Gonzalez.
  21st European Conference on Computer Systems (EuroSys 2026).

2025

• Rethinking RPC Communication for Microservices-based Applications.
  Xiangfeng Zhu, Yang Zhou, Yuyao Wang, Xiangyu Gao, Arvind Krishnamurthy, Sam Kumar, Ratul Mahajan, and Danyang Zhuo.
  ACM SIGOPS 20th Workshop on Hot Topics in Operating Systems (HotOS XX).

• High-level Programming for Application Networks.
  Xiangfeng Zhu, Yuyao Wang, Banruo Liu, Yongtong Wu, Nikola Bojanic, Jingrong Chen, Gilbert Louis Bernstein, Arvind Krishnamurthy, Sam Kumar, Ratul Mahajan, and Danyang Zhuo.
  22nd USENIX Symposium on Networked Systems Design and Implementation (NSDI 2025).

2023

• Rethinking System Design for Expressive Cryptography.
  Sam Kumar.
  PhD Dissertation. University of California, Berkeley.
  Original/official version available on ProQuest and as Technical Report No. UCB/EECS-2023-194.

• Skyplane: Optimizing Transfer Cost and Throughput Using Cloud-Aware Overlays.
  Paras Jain, Sam Kumar, Sarah Wooders, Shishir G. Patil, Joseph E. Gonzalez, and Ion Stoica.
  20th USENIX Symposium on Networked Systems Design and Implementation (NSDI 2023).

2021

• MAGE: Nearly Zero-Cost Virtual Memory for Secure Computation.
  Sam Kumar, David E. Culler, and Raluca Ada Popa.
  15th USENIX Symposium on Operating Systems Design and Implementation (OSDI 2021).
  Received a Jay Lepreau Best Paper Award at OSDI 2021.

2020

• Performant TCP for Low-Power Wireless Networks.
  Sam Kumar, Michael P Andersen, Hyung-Sin Kim, and David E. Culler.
  17th USENIX Symposium on Networked Systems Design and Implementation (NSDI 2020).
  Received an Applied Networking Research Prize from the IETF/IRTF in 2022.

• Ghostor: Toward a Secure Data-Sharing System from Decentralized Trust.
  (*Co-primary authors) *Yuncong Hu, *Sam Kumar, and Raluca Ada Popa.
  17th USENIX Symposium on Networked Systems Design and Implementation (NSDI 2020).

2019

• JEDI: Many-to-Many End-to-End Encryption and Key Delegation for IoT.
  Extended Version (published as Technical Report No. arXiv:1905.13369 [cs.CR]).
  Sam Kumar, Yuncong Hu, Michael P Andersen, Raluca Ada Popa, and David E. Culler.
  28th USENIX Security Symposium (USENIX Security 2019).

• WAVE: A Decentralized Authorization Framework with Transitive Delegation.
  Michael P Andersen, Sam Kumar, Moustafa AbdelBaky, Gabe Fierro, John Kolb, Hyung-Sin Kim, David E. Culler, and Raluca Ada Popa.
  28th USENIX Security Symposium (USENIX Security 2019).

• Thread/OpenThread: A Compromise in Low-Power Wireless Multihop Network Architecture for the Internet of Things.
  Hyung-Sin Kim, Sam Kumar, and David E. Culler.
  IEEE Communications Magazine, Vol. 57, No. 7 (ComMag July 2019).

2018

• System Architecture Directions for Post-SoC/32-bit Networked Sensors.
  Hyung-Sin Kim, Michael P Andersen, Kaifei Chen, Sam Kumar, William J. Zhao, Kevin Ma, and David E. Culler.
  16th ACM Conference on Embedded Networked Sensor Systems (SenSys 2018).
  Received a Best Paper Runner-Up Award at SenSys 2018.

• Demo Abstract: Bringing Full-Scale TCP to Low-Power Networks.
  Sam Kumar, Michael P Andersen, Hyung-Sin Kim, and David E. Culler.
  16th ACM Conference on Embedded Networked Sensor Systems (SenSys 2018).

2016

• Well-Connected Microzones for Increased Building Efficiency and Occupant Comfort.
  Michael P Andersen, Gabe Fierro, Sam Kumar, Joyce Kim, Edward A. Arens, Hui Zhang, Paul Raftery, and David E. Culler.
  2016 ACEEE Summer Study on Energy Efficiency in Buildings (SSB 2016).

2015

• DISTIL: Design and Implementation of a Scalable Synchrophasor Data Processing System.
  Michael P Andersen, Sam Kumar, Connor Brooks, Alexandra von Meier, and David E. Culler.
  2015 IEEE International Conference on Smart Grid Communications (SmartGridComm 2015).

• Poster Abstract: Well-Connected Microzones for Increased Building Efficiency and Occupant Comfort.
  Michael P Andersen, Gabe Fierro, Sam Kumar, Michael Chen, Leonard Truong, Joyce Kim, Edward A. Arens, Hui Zhang, Paul Raftery, and David E. Culler.
  2nd ACM International Conference on Embedded Systems for Energy-Efficient Built Environments (BuildSys 2015).

Software

Here are some software artifacts that have resulted from my research over the years:

• TCPlp: TCP for Low Power Wireless Networks
  Published at NSDI 2020
  Relevant GitHub repositories: Adoption in OpenThread, Code for Reproducibility

• MAGE: Memory-Aware Garbling Engine
  Published at OSDI 2021
  Relevant GitHub repositories: MAGE System, Scripts for Experiments

• JEDI: Joining Encryption and Delegation for IoT
  Published at USENIX Security 2019
  Relevant GitHub repositories: JEDI Cryptography Library, JEDI Prototype Implementation

• GDPFS: The Global Data Plane File System
  CS 262A Project Report (Spring 2016)
  Relevant GitHub repositories: GDPFS Implementation, FIG Tree Library (C), FIG Tree Prototype (Java)

• Mr. Plotter: The Multiresolution Plotter (Project Page)
  Project Report (published as Technical Report No. UCB/EECS-2018-85)
  Relevant GitHub repositories: Mr. Plotter Web Application, Mr. Plotter Desktop Application, Mr. Plotter QML Library