Research

I am a computer architect with broad interests in adjacent areas. Recently, a lot of my work has been related to security (from applied cryptography to hardware-based attacks and defenses) and domain-specific acceleration (from algorithm to hardware design). Here is my CV and Google Scholar.

Some recent work:

For more papers (+ links to talks, etc.), click to expand.

Papers

  • GoFetch: Breaking Constant-Time Cryptographic Implementations Using Data Memory-Dependent Prefetchers, Security 2024 [info page
  • ConjunCT: Learning Inductive Invariants to Prove Unbounded Instruction Safety Against Microarchitectural Timing Attacks, Oakland/SP 2024
  • GPU.zip: On the Side-Channel Implications of Hardware-Based Graphical Data Compression, Oakland/SP 2024 [info page
  • Last-Level Cache Side-Channel Attacks Are Feasible in the Modern Public Cloud, ASPLOS 2024
  • Everywhere All at Once: Co-Location Attacks on Public Cloud FaaS, ASPLOS 2024
  • Secure-by-Construction Design Methodology for CPUs: Implementing Secure Speculation on the RTL, ICCAD 2023
  • TeAAL: A Declarative Framework for Modeling Sparse Tensor Accelerators, MICRO 2023 [paperIEEE Micro Top Picks 2023 Honorable Mention
  • Declassiflow: A Static Analysis for Modeling Non-Speculative Knowledge to Relax Speculative Execution Security Measures, CCS 2023 [paper
  • Synchronization Storage Channels (S2C): Timer-less Cache Side-Channel Attacks on the Apple M1 via Hardware Synchronization Instructions, Security 2023 [paper, slides, conference talk
  • DVFS Frequently Leaks Secrets: Hertzbleed Attacks Beyond SIKE, Cryptography, and CPU-Only Data, Oakland/SP 2023 [info page] [paper
  • All your PC are belong to us: Exploiting Non-control-transfer Instruction BTB Updates for Dynamic PC Extraction, ISCA 2023 [paper
  • Hertzbleed: Turning Power Side-Channel Attacks Into Remote Timing Attacks on x86, Top Picks 2023 [paper
  • Accelerating Sparse Data Orchestration via Dynamic Reflexive Tiling, ASPLOS 2023 [paper] [conference talk
  • Untangle: A Principled Framework to Design Low-Leakage, High-Performance Dynamic Partitioning Schemes, ASPLOS 2023 [paper] [conference talkIEEE Micro Top Picks 2023 Honorable Mention
  • Pagoda: Towards Binary Code Privacy Protection with SGX-based Execute-Only Memory, SEED 2022 [paper
  • Hertzbleed: Turning Power Side-Channel Attacks Into Remote Timing Attacks on x86, Security 2022 [info page] [paper, conference talkPwnie Award -- Best Cryptographic AttackIEEE Micro Top Picks 2022Intel Bug Bounty
  • Binoculars: Contention-Based Side-Channel Attacks Exploiting the Page Walker, Security 2022 [paper, slides, conference talk
  • Augury: Using Data Memory-Dependent Prefetchers to Leak Data at Rest, Oakland/SP 2022 [info page] [paper] [conference talkCSAW'22 Applied Research Competition Runner-Up (2nd place)
  • Graphite: Optimizing Graph Neural Networks on CPUs Through Cooperative Software-Hardware Techniques, ISCA 2022 [paper] [conference talk
  • SynthCT: Towards Portable Constant-Time Code, NDSS 2022 [paper, conference talk
  • Optimizing Selective Protection for CNN Resilience, ISSRE 2021 [paper
  • Speculative Privacy Tracking (SPT): Leaking Information From Speculative Execution Without Compromising Privacy, MICRO 2021 [paper] [conference talk
  • SumMerge: An Efficient Algorithm and Implementation for Weight Repetition-Aware DNN Inference, ICS 2021 [paper
  • Opening Pandora's Box: A Systematic Study of New Ways Microarchitecture Can Leak Private Data, ISCA 2021 [paper] [conference talkIntel Hardware Security Academic Award 2022 (Honorable Mention)
  • Leaking Secrets Through Compressed Caches, Top Picks 2021 [paper
  • Lord of the Ring(s): Side Channel Attacks on the CPU On-Chip Ring Interconnect Are Practical, Security 2021 [paper, slides, conference talkNominee for Pwnie Award -- Most Innovative Research
  • Double-Cross Attacks: Subverting Active Learning Systems, Security 2021 [paper, slides, conference talk
  • Speculative Interference Attacks: Breaking Invisible Speculation Schemes, ASPLOS 2021 [paper
  • Jamais Vu: Thwarting Microarchitectural Replay Attacks, ASPLOS 2021 [paper] [slides
  • Streamline: A Fast, Flushless Cache Covert-Channel Attack by Enabling Asynchronous Collusion, ASPLOS 2021 [paper] [conference talk
  • Mind Mappings: Enabling Efficient Algorithm-Accelerator Mapping Space Search, ASPLOS 2021 [paper] [lightning talk
  • Speculative Taint Tracking (STT): A Comprehensive Protection for Speculatively-Accessed Data, CACM 2021 [paper
  • CoTracer and RokWall: Privacy Preserving University Health Apps for COVID-19, NDSS-CoronaDef 2021 [paper
  • DOVE: A Data-Oblivious Virtual Environment, NDSS 2021 [paper] [conference talk
  • SparseTrain: Leveraging Dynamic Sparsity in Software for Training DNNs on General-Purpose SIMD Processors, PACT 2020 [paper
  • SAVE: Sparsity-Aware Vector Engine for Accelerating DNN Training and Inference on CPUs, MICRO 2020 [paper] [conference talk
  • Speculation Invariance (InvarSpec): Faster Safe Execution Through Program Analysis, MICRO 2020 [paper] [conference talk
  • PyTorchFI: A Runtime Perturbation Tool for DNNs, DSN-DSML 2020 [paper] [open-source release
  • Speculative Data-Oblivious Execution: Mobilizing Safe Prediction For Safe and Efficient Speculative Execution, ISCA 2020 [paper] [open-source releaseIntel Hardware Security Academic Award 2021 (First Place)
  • Scalable Validation of Binary Lifters, PLDI 2020 [paper] [open-source release
  • HarDNN: Feature Map Vulnerability Evaluation in CNNs, SARA 2020 [paper
  • Custos: Practical Tamper-Evident Auditing of Operating Systems Using Trusted Execution, NDSS 2020 [paper, slides, conference talk] [open-source release
  • Creating Foundations for Secure Microarchitectures with Data-Oblivious ISA Extensions, Top Picks 2020 [paper
  • Speculative Taint Tracking (STT): A Comprehensive Protection for Speculatively Accessed Data, Top Picks 2020 [paper
  • MicroScope: Enabling Microarchitectural Replay Attacks, Top Picks 2020 [paper
  • Game of Threads: Enabling Asynchronous Poisoning Attacks, ASPLOS 2020 [paper] [conference talk] [open-source release
  • Safecracker: Leaking Secrets through Compressed Caches, ASPLOS 2020 [paper] [conference talk] [open-source releaseIEEE Micro Top Picks 2021
  • Cache Telepathy: Leveraging Shared Resource Attacks to Learn DNN Architectures, Security 2020 [paper, slides, conference talk
  • ExTensor: An Accelerator for Sparse Tensor Algebra, MICRO 2019 [paperIEEE Micro Top Picks 2020 Honorable Mention
  • Speculative Taint Tracking (STT): A Comprehensive Protection for Speculatively Accessed Data, MICRO 2019 [paper] [formal analysis] [open-source releaseBest Paper AwardIEEE Micro Top Picks 2020CACM Highlight
  • A Retrospective on Path ORAM, TCAD 2019 [paper
  • Approximate Checkers, WAX 2019 [paper
  • MicroScope: Enabling Microarchitectural Replay Attacks, ISCA 2019 [paper] [conference talk] [open-source releaseHighest ranked paper in double-blind review processIEEE Micro Top Picks 2020
  • SecDir: Secure Directories to Defeat Directory Side Channel Attacks, ISCA 2019 [paper
  • gem5-Approxilyzer: an Open Source Tool for Application-level Soft Error Analysis, DSN 2019 [paper] [open-source release
  • Buffets: An Efficient and Composable Storage Idiom for Explicit Decoupled Data Orchestration, ASPLOS 2019 [paper] [lightning talk] [open-source releaseIEEE Micro Top Picks 2020 Honorable Mention
  • Minotaur: Adapting Software Testing Techniques for Hardware Errors, ASPLOS 2019 [paper] [conference talk
  • Data Oblivious ISA Extensions for Side Channel-Resistant and High Performance Computing, NDSS 2019 [paper] [conference talk] [open-source releaseDistinguished Paper FinalistCSAW Applied Research Competition FinalistIEEE Micro Top Picks 2020
  • Attack Directories, Not Caches: Side Channel Attacks in a Non-Inclusive World, Oakland/SP 2019 [paper] [conference talk
  • InvisiSpec: Making Speculative Execution Invisible in the Cache Hierarchy, MICRO 2018 [paper] [lightning talk] [corrigendum] [corrected paper] [open-source releaseIEEE Micro Top Picks 2019 Honorable Mention
  • Morph: Flexible Acceleration for 3D CNN-based Video Understanding, MICRO 2018 [paper
  • UCNN: Exploiting Computational Reuse in Deep Neural Networks via Weight Repetition, ISCA 2018 [paper] [lightning talk
  • Path ORAM: An Extremely Simple Oblivious RAM Protocol, JACM 2018 [paper
  • ZeroTrace: Oblivious Memory Primitives from Intel SGX, NDSS 2018 [paper] [open-source release
  • Design and Implementation of the Ascend Secure Processor, TDSC 2017 [paper
  • Asymptotically tight bounds for composing ORAM with PIR, PKC 2017 [paper
  • HOP: Hardware makes Obfuscation Practical, NDSS 2017 [paper] [open-source release
  • Onion ORAM: A Constant Bandwidth Blowup Oblivious RAM, TCC 2016 [paper] [conference talk
  • Constants Count: Practical Improvements to Oblivious RAM, Security 2015 [paper
  • PrORAM: Dynamic Prefetcher for Oblivious RAM, ISCA 2015 [paper
  • A Low-Latency, Low-Area Hardware Oblivious RAM Controller, FCCM 2015 [paper] [open-source release
  • Freecursive ORAM: [Nearly] Free Recursion and Integrity Verification for Position-based Oblivious RAM, ASPLOS 2015 [paper
  • Suppressing the Oblivious RAM Timing Channel While Making Information Leakage and Program Efficiency Trade-offs, HPCA 2014 [paper
  • Path ORAM: An Extremely Simple Oblivious RAM Protocol, CCS 2013 [paperBest Student Paper AwardTop Picks in Hardware & Embedded Security 2018Test of Time Award
  • Generalized External Interaction with Tamper-Resistant Hardware with Bounded Information Leakage, CCSW 2013 [paper
  • A Framework to Accelerate Sequential Programs on Homogeneous Multicores, VLSI-SOC 2013 [paper
  • Integrity Verification for Path Oblivious-RAM, HPEC 2013 [paper
  • Design Space Exploration and Optimization of Path Oblivious RAM in Secure Processors, ISCA 2013 [paper
  • Towards an Interpreter for Efficient Encrypted Computation, CCSW 2012 [paper
  • A Secure Processor Architecture for Encrypted Computation on Untrusted Programs, STC 2012 [paper
  • HORNET: a cycle-level multicore simulator, TCAD 2012 [paper
  • A Low-overhead Dynamic Optimization Framework on Multicores (short paper), PACT 2012 [paper
  • Exploring Many-core Design Templates for FPGAs and ASICs, IJRC 2012 [paper
  • Scalable Accurate Multicore Simulation in the 1000 core era, ISPASS 2011 [paper
  • Brief Announcement: Distributed Shared Memory based on Computation Migration (short paper), SPAA 2011 [paper
  • Bridging the GPGPU-FPGA Efficiency Gap (short paper), FPGA 2011 [paper
  • MARC: A Many-Core Approach to Reconfigurable Computing, ReConFig 2010 [paper
  • ParaLearn: A Massively Parallel, Scalable System for Learning Interaction Networks on FPGAs, ICS 2010 [paper] [slidesBest Student Paper Award

Papers

  • GoFetch: Breaking Constant-Time Cryptographic Implementations Using Data Memory-Dependent Prefetchers
    Boru Chen, Yingchen Wang, Pradyumna Shome, Christopher W. Fletcher, David Kohlbrenner, Riccardo Paccagnella, Daniel Genkin
    Appears in the Proceedings of the USENIX Security Symposium (Security), 2024
    [info page

  • ConjunCT: Learning Inductive Invariants to Prove Unbounded Instruction Safety Against Microarchitectural Timing Attacks
    Sushant Dinesh, Madhusudan Parthasarathy, Christopher W. Fletcher
    To appear in the Proceedings of the IEEE Symposium on Security and Privacy (Oakland/SP), 2024

  • GPU.zip: On the Side-Channel Implications of Hardware-Based Graphical Data Compression
    Yingchen Wang, Riccardo Paccagnella, Zhao Gang, Willy R. Vasquez, David Kohlbrenner, Hovav Shacham, Christopher W. Fletcher
    Appears in the Proceedings of the IEEE Symposium on Security and Privacy (Oakland/SP), 2024
    [info page

  • Last-Level Cache Side-Channel Attacks Are Feasible in the Modern Public Cloud
    Zirui Zhao, Adam Morrison, Christopher W. Fletcher, Josep Torrellas
    To appear in the Proceedings of the ACM Architectural Support for Programming Languages and Operating Systems (ASPLOS), 2024

  • Everywhere All at Once: Co-Location Attacks on Public Cloud FaaS
    Zirui Zhao, Adam Morrison, Christopher W. Fletcher, Josep Torrellas
    To appear in the Proceedings of the ACM Architectural Support for Programming Languages and Operating Systems (ASPLOS), 2024

  • Secure-by-Construction Design Methodology for CPUs: Implementing Secure Speculation on the RTL
    Tobias Jauch, Alex Wezel, Mohammad R. Fadiheh, Philipp Schmitz, Sayak Ray, Jason M. Fung, Christopher W. Fletcher, Dominik Stoffel, Wolfgang Kunz
    To appear in the Proceedings of the IEEE/ACM 2022 International Conference on Computer-Aided Design (ICCAD), 2023

  • TeAAL: A Declarative Framework for Modeling Sparse Tensor Accelerators
    Nandeeka Nayak, Toluwanimi Odemuyiwa, Shubham Ugare, Christopher W. Fletcher, Michael Pellauer, Joel Emer
    Appears in the Proceedings of the ACM/IEEE International Symposium on Microarchitecture (MICRO), 2023
    IEEE Micro Top Picks 2023 Honorable Mention
    [paper

  • Declassiflow: A Static Analysis for Modeling Non-Speculative Knowledge to Relax Speculative Execution Security Measures
    Rutvik Choudhary, Alan Wang, Zirui Zhao, Adam Morrison, Christopher W. Fletcher
    Appears in the Proceedings of the ACM Conference on Computer and Communications Security (CCS), 2023
    [paper

  • Synchronization Storage Channels (S2C): Timer-less Cache Side-Channel Attacks on the Apple M1 via Hardware Synchronization Instructions
    Jiyong Yu, Aishani Dutta, Trent Jaeger, David Kohlbrenner, Christopher W. Fletcher
    Appears in the Proceedings of the USENIX Security Symposium (Security), 2023
    [paper, slides, conference talk

  • DVFS Frequently Leaks Secrets: Hertzbleed Attacks Beyond SIKE, Cryptography, and CPU-Only Data
    Yinchen Wang, Riccardo Paccagnella, Alan Wandke, Zhao Gang, Grant Garrett-Grossman, Christopher W. Fletcher, David Kohlbrenner, Hovav Shacham
    Appears in the Proceedings of the IEEE Symposium on Security and Privacy (Oakland/SP), 2023
    [info page] [paper

  • All your PC are belong to us: Exploiting Non-control-transfer Instruction BTB Updates for Dynamic PC Extraction
    Jiyong Yu, Trent Jaeger, Christopher W. Fletcher
    Appears in the Proceedings of the ACM/IEEE International Symposium on Computer Architecture (ISCA), 2023
    [paper

  • Hertzbleed: Turning Power Side-Channel Attacks Into Remote Timing Attacks on x86
    Yinchen Wang, Riccardo Paccagnella, Elizabeth He, Hovav Shacham, Christopher W. Fletcher, David Kohlbrenner (Y. Wang and R. Paccagnella shared lead author)
    Appears in the IEEE MICRO Top Picks Special Issue (Top Picks), 2023
    [paper

  • Accelerating Sparse Data Orchestration via Dynamic Reflexive Tiling
    Toluwanimi Odemuyiwa, Hadi Asghari-Moghaddam, Michael Pellauer, Kartik Hegde, Po-An Tsai, Neal Crago, Aamer Jaleel, John Owens, Edgar Solomonik, Joel Emer, Christopher W. Fletcher
    Appears in the Proceedings of the ACM Architectural Support for Programming Languages and Operating Systems (ASPLOS), 2023
    [paper] [conference talk

  • Untangle: A Principled Framework to Design Low-Leakage, High-Performance Dynamic Partitioning Schemes
    Zirui Zhao, Adam Morrison, Christopher W. Fletcher, Josep Torrellas
    Appears in the Proceedings of the ACM Architectural Support for Programming Languages and Operating Systems (ASPLOS), 2023
    IEEE Micro Top Picks 2023 Honorable Mention
    [paper] [conference talk

  • Pagoda: Towards Binary Code Privacy Protection with SGX-based Execute-Only Memory
    Jiyong Yu, Xinyang Ge, Trent Jaeger, Christopher W. Fletcher, Weidong Cui
    Appears in the Proceedings of the IEEE International Symposium on Secure and Private Execution Environment Design (SEED), 2022
    [paper

  • Hertzbleed: Turning Power Side-Channel Attacks Into Remote Timing Attacks on x86
    Yinchen Wang, Riccardo Paccagnella, Elizabeth He, Hovav Shacham, Christopher W. Fletcher, David Kohlbrenner (Y. Wang and R. Paccagnella shared lead author)
    Appears in the Proceedings of the USENIX Security Symposium (Security), 2022
    Pwnie Award -- Best Cryptographic Attack
    IEEE Micro Top Picks 2022
    Intel Bug Bounty
    [info page] [paper, conference talk

  • Binoculars: Contention-Based Side-Channel Attacks Exploiting the Page Walker
    Zirui Zhao, Adam Morrison, Christopher W. Fletcher, Josep Torrellas
    Appears in the Proceedings of the USENIX Security Symposium (Security), 2022
    [paper, slides, conference talk

  • Augury: Using Data Memory-Dependent Prefetchers to Leak Data at Rest
    Jose Rodrigo Sanchez Vicarte, Michael Flanders, Riccardo Paccagnella, Grant Garrett-Grossman, Adam Morrison, Christopher W. Fletcher, David Kohlbrenner (J. Vicarte and M. Flanders shared lead author)
    Appears in the Proceedings of the IEEE Symposium on Security and Privacy (Oakland/SP), 2022
    CSAW'22 Applied Research Competition Runner-Up (2nd place)
    [info page] [paper] [conference talk

  • Graphite: Optimizing Graph Neural Networks on CPUs Through Cooperative Software-Hardware Techniques
    Zhangxiaowen Gong; Houxiang Ji, Yao Yao, Christopher W. Fletcher; Christopher J. Hughes; Josep Torrellas
    Appears in the Proceedings of the ACM/IEEE International Symposium on Computer Architecture (ISCA), 2022
    [paper] [conference talk

  • SynthCT: Towards Portable Constant-Time Code
    Sushant Dinesh, Grant Garrett-Grossman, Christopher W. Fletcher
    Appears in the Proceedings of the Internet Society Network and Distributed System Security Symposium (NDSS), 2022
    [paper, conference talk

  • Optimizing Selective Protection for CNN Resilience
    Abdulrahman Mahmoud, Siva Kumar Sastry Hari, Christopher W. Fletcher, Sarita V. Adve, Charbel Sakr, Naresh Shanbhag, Pavlo Molchanov, Michael B. Sullivan, Timothy Tsai, Stephen W. Keckler
    Appears in the Proceedings of the International Symposium on Software Reliability Engineering (ISSRE), 2021
    [paper

  • Speculative Privacy Tracking (SPT): Leaking Information From Speculative Execution Without Compromising Privacy
    Rutvik Choudhary, Jiyong Yu, Christopher W. Fletcher, Adam Morrison
    Appears in the Proceedings of the ACM/IEEE International Symposium on Microarchitecture (MICRO), 2021
    [paper] [conference talk

  • SumMerge: An Efficient Algorithm and Implementation for Weight Repetition-Aware DNN Inference
    Rohan Prabhakar, Sachit Kuhar, Rohit Agrawal, Christopher Hughes, Christopher W. Fletcher
    Appears in the Proceedings of the International Conference on Supercomputing (ICS), 2021
    [paper

  • Opening Pandora's Box: A Systematic Study of New Ways Microarchitecture Can Leak Private Data
    Jose Rodrigo Sanchez Vicarte, Pradyumna Shome, Nandeeka Nayak, Caroline Trippel, Adam Morrison, David Kohlbrenner, Christopher W. Fletcher
    Appears in the Proceedings of the ACM/IEEE International Symposium on Computer Architecture (ISCA), 2021
    Intel Hardware Security Academic Award 2022 (Honorable Mention)
    [paper] [conference talk

  • Leaking Secrets Through Compressed Caches
    Po-An Tsai, Andres Sanchez, Christopher W. Fletcher, Daniel Sanchez
    Appears in the IEEE MICRO Top Picks Special Issue (Top Picks), 2021
    [paper

  • Lord of the Ring(s): Side Channel Attacks on the CPU On-Chip Ring Interconnect Are Practical
    Riccardo Paccagnella, Licheng Luo, Christopher W. Fletcher
    Appears in the Proceedings of the USENIX Security Symposium (Security), 2021
    Nominee for Pwnie Award -- Most Innovative Research
    [paper, slides, conference talk

  • Double-Cross Attacks: Subverting Active Learning Systems
    Jose Rodrigo Sanchez Vicarte, Gang Wang, Christopher W. Fletcher
    Appears in the Proceedings of the USENIX Security Symposium (Security), 2021
    [paper, slides, conference talk

  • Speculative Interference Attacks: Breaking Invisible Speculation Schemes
    Mohammad Behnia, Prateek Sahu, Riccardo Paccagnella, Jiyong Yu, Zirui Zhao, Xiang Zou, Thomas Unterluggauer, Josep Torrellas, Carlos Rozas, Adam Morrison, Frank Mckeen, Fangfei Liu, Ron Gabor, Christopher W. Fletcher, Abhishek Basak, Alaa Alameldeen
    Appears in the Proceedings of the ACM Architectural Support for Programming Languages and Operating Systems (ASPLOS), 2021
    [paper

  • Jamais Vu: Thwarting Microarchitectural Replay Attacks
    Dimitrios Skarlatos, Zirui Zhao, Riccardo Paccagnella, Christopher W. Fletcher, Josep Torrellas
    Appears in the Proceedings of the ACM Architectural Support for Programming Languages and Operating Systems (ASPLOS), 2021
    [paper] [slides

  • Streamline: A Fast, Flushless Cache Covert-Channel Attack by Enabling Asynchronous Collusion
    Gururaj Saileshwar, Christopher W. Fletcher, Moinuddin Qureshi
    Appears in the Proceedings of the ACM Architectural Support for Programming Languages and Operating Systems (ASPLOS), 2021
    [paper] [conference talk

  • Mind Mappings: Enabling Efficient Algorithm-Accelerator Mapping Space Search
    Kartik Hegde, Po-An Tsai, Sitao Huang, Vikas Chandra, Angshuman Parashar, Christopher W. Fletcher
    Appears in the Proceedings of the ACM Architectural Support for Programming Languages and Operating Systems (ASPLOS), 2021
    [paper] [lightning talk

  • Speculative Taint Tracking (STT): A Comprehensive Protection for Speculatively-Accessed Data
    Jiyong Yu, Mengjia Yan, Artem Khyzha, Adam Morrison, Josep Torrellas, Christopher W. Fletcher
    Appears in the Communications of the ACM as a Research Highlight (CACM), 2021
    [paper

  • CoTracer and RokWall: Privacy Preserving University Health Apps for COVID-19
    Vikram Sharma Mailthody, Amit Agarwal, Nicholas Chen, Andrew Miller, Sanjay Patel, Edward Richter, Christopher W. Fletcher, Mohammad Behnia, Ruihao Yao, Qihao Wang, Jinjun Xiong, Lijian Wang, Leihao Chen, James Wei, Vedant Agarwal, Churan He
    Appears in the Proceedings of the CoronaDef Workshop (NDSS-CoronaDef), 2021
    [paper

  • DOVE: A Data-Oblivious Virtual Environment
    Hyun Bin Lee, Tushar Jois, Christopher W. Fletcher, Carl A. Gunter
    Appears in the Proceedings of the Internet Society Network and Distributed System Security Symposium (NDSS), 2021
    [paper] [conference talk

  • SparseTrain: Leveraging Dynamic Sparsity in Software for Training DNNs on General-Purpose SIMD Processors
    Zhangxiaowen Gong, Houxiang Ji, Christopher W. Fletcher, Christopher J. Hughes, Josep Torrellas
    Appears in the Proceedings of the International Conference on Parallel Architectures and Compilation Techniques (PACT), 2020
    [paper

  • SAVE: Sparsity-Aware Vector Engine for Accelerating DNN Training and Inference on CPUs
    Zhangxiaowen Gong, Houxiang Ji, Christopher W. Fletcher, Christopher Hughes, Sara Baghsorkhi, Josep Torrellas
    Appears in the Proceedings of the ACM/IEEE International Symposium on Microarchitecture (MICRO), 2020
    [paper] [conference talk

  • Speculation Invariance (InvarSpec): Faster Safe Execution Through Program Analysis
    Zirui Zhao, Houxiang Ji, Mengjia Yan, Jiyong Yu, Christopher W. Fletcher, Adam Morrison, Darko Marinov, Josep Torrellas
    Appears in the Proceedings of the ACM/IEEE International Symposium on Microarchitecture (MICRO), 2020
    [paper] [conference talk

  • PyTorchFI: A Runtime Perturbation Tool for DNNs
    Abdulrahman Mahmoud, Neeraj Aggarwal, Alex Nobbe, Jose Rodrigo Sanchez Vicarte, Sarita Adve, Christopher W. Fletcher, Iuri Frosio, Siva Kumar Sastry Hari
    Appears in the Proceedings of the Dependable and Secure Machine Learning (DSN-DSML), 2020
    [paper] [open-source release

  • Speculative Data-Oblivious Execution: Mobilizing Safe Prediction For Safe and Efficient Speculative Execution
    Jiyong Yu, Namrata Mantri, Josep Torrellas, Adam Morrison, Christopher W. Fletcher
    Appears in the Proceedings of the ACM/IEEE International Symposium on Computer Architecture (ISCA), 2020
    Intel Hardware Security Academic Award 2021 (First Place)
    [paper] [open-source release

  • Scalable Validation of Binary Lifters
    Sandeep Dasgupta, Sushant Dinesh, Deepan Venkatesh, Vikram Adve, Christopher W. Fletcher
    Appears in the Proceedings of the SIGPLAN Conference on Programming Language Design and Implementation (PLDI), 2020
    [paper] [open-source release

  • HarDNN: Feature Map Vulnerability Evaluation in CNNs
    Abdulrahman Mahmoud, Siva Kumar Sastry Hari, Christopher W. Fletcher, Sarita V. Adve, Charbel Sakr, Naresh Shanbhag, Pavlo Molchanov, Michael B. Sullivan, Timothy Tsai and Stephen W. Keckler
    Appears in the Proceedings of the Workshop on Secure and Resilient Autonomy (SARA), 2020
    [paper

  • Custos: Practical Tamper-Evident Auditing of Operating Systems Using Trusted Execution
    Riccardo Paccagnella, Pubali Datta, Wajih Hassan, Adam Bates, Christopher W. Fletcher, Andrew Miller, Dave Tian
    Appears in the Proceedings of the Internet Society Network and Distributed System Security Symposium (NDSS), 2020
    [paper, slides, conference talk] [open-source release

  • Creating Foundations for Secure Microarchitectures with Data-Oblivious ISA Extensions
    Jiyong Yu, Lucas Hsiung, Mohamad El Hajj, Christopher W. Fletcher
    Appears in the IEEE MICRO Top Picks Special Issue (Top Picks), 2020
    [paper

  • Speculative Taint Tracking (STT): A Comprehensive Protection for Speculatively Accessed Data
    Jiyong Yu, Mengjia Yan, Artem Khyzha, Adam Morrison, Josep Torrellas, Christopher W. Fletcher
    Appears in the IEEE MICRO Top Picks Special Issue (Top Picks), 2020
    [paper

  • MicroScope: Enabling Microarchitectural Replay Attacks
    Dimitrios Skarlatos, Mengjia Yan, Bhargava Gopireddy, Read Sprabery, Josep Torrellas, Christopher W. Fletcher
    Appears in the IEEE MICRO Top Picks Special Issue (Top Picks), 2020
    [paper

  • Game of Threads: Enabling Asynchronous Poisoning Attacks
    Jose Rodrigo Sanchez Vicarte, Ben Schreiber, Riccardo Paccagnella, Christopher W. Fletcher
    Appears in the Proceedings of the ACM Architectural Support for Programming Languages and Operating Systems (ASPLOS), 2020
    [paper] [conference talk] [open-source release

  • Safecracker: Leaking Secrets through Compressed Caches
    Po-An Tsai, Andres Sanchez, Christopher W. Fletcher, Daniel Sanchez
    Appears in the Proceedings of the ACM Architectural Support for Programming Languages and Operating Systems (ASPLOS), 2020
    IEEE Micro Top Picks 2021
    [paper] [conference talk] [open-source release

  • Cache Telepathy: Leveraging Shared Resource Attacks to Learn DNN Architectures
    Mengjia Yan, Christopher W. Fletcher, Josep Torrellas
    Appears in the Proceedings of the USENIX Security Symposium (Security), 2020
    [paper, slides, conference talk

  • ExTensor: An Accelerator for Sparse Tensor Algebra
    Kartik Hegde, Hadi Asghari-Moghaddam, Michael Pellauer, Neal Crago, Aamer Jaleel, Edgar Solomonik, Joel Emer, Christopher W. Fletcher
    Appears in the Proceedings of the ACM/IEEE International Symposium on Microarchitecture (MICRO), 2019
    IEEE Micro Top Picks 2020 Honorable Mention
    [paper

  • Speculative Taint Tracking (STT): A Comprehensive Protection for Speculatively Accessed Data
    Jiyong Yu, Mengjia Yan, Artem Khyzha, Adam Morrison, Josep Torrellas, Christopher W. Fletcher
    Appears in the Proceedings of the ACM/IEEE International Symposium on Microarchitecture (MICRO), 2019
    Best Paper Award
    IEEE Micro Top Picks 2020
    CACM Highlight
    [paper] [formal analysis] [open-source release

  • A Retrospective on Path ORAM
    Emil Stefanov, Marten van Dijk, Elaine Shi, Christopher W. Fletcher, Ling Ren, Xiangyao Yu, Srinivas Devadas
    Appears in the IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems (TCAD), 2019
    [paper

  • Approximate Checkers
    Abdulrahman Mahmoud, Paul Reckamp, Panqiu Tang, Christopher W. Fletcher, Sarita V. Adve
    Appears in the Proceedings of the Workshop on Approximate Computing Across the Stack (WAX), 2019
    [paper

  • MicroScope: Enabling Microarchitectural Replay Attacks
    Dimitrios Skarlatos, Mengjia Yan, Bhargava Gopireddy, Read Sprabery, Josep Torrellas, Christopher W. Fletcher
    Appears in the Proceedings of the ACM/IEEE International Symposium on Computer Architecture (ISCA), 2019
    Highest ranked paper in double-blind review process
    IEEE Micro Top Picks 2020
    [paper] [conference talk] [open-source release

  • SecDir: Secure Directories to Defeat Directory Side Channel Attacks
    Mengjia Yan, Jen-Yang Wen, Christopher W. Fletcher, Josep Torrellas
    Appears in the Proceedings of the ACM/IEEE International Symposium on Computer Architecture (ISCA), 2019
    [paper

  • gem5-Approxilyzer: an Open Source Tool for Application-level Soft Error Analysis
    Radha Venkatagiri, Khalique Ahmed, Abdulrahman Mahmoud, Sasa Misailovic, Darko Marinov, Christopher W. Fletcher, and Sarita V. Adve
    Appears in the Proceedings of the IEEE/IFIP International Conference on Dependable Systems and Networks (DSN), 2019
    [paper] [open-source release

  • Buffets: An Efficient and Composable Storage Idiom for Explicit Decoupled Data Orchestration
    Michael Pellauer, Yakun Sophia Shao, Jason Clemons, Neal Crago, Kartik Hegde, Rangarajan Venkatesan, Stephen W. Keckler, Christopher W. Fletcher, Joel Emer
    Appears in the Proceedings of the ACM Architectural Support for Programming Languages and Operating Systems (ASPLOS), 2019
    IEEE Micro Top Picks 2020 Honorable Mention
    [paper] [lightning talk] [open-source release

  • Minotaur: Adapting Software Testing Techniques for Hardware Errors
    Abdulrahman Mahmoud, Radha Venkatagiri, Khalique Ahmed, Sasa Misailovic, Darko Marinov, Christopher W. Fletcher, Sarita V. Adve
    Appears in the Proceedings of the ACM Architectural Support for Programming Languages and Operating Systems (ASPLOS), 2019
    [paper] [conference talk

  • Data Oblivious ISA Extensions for Side Channel-Resistant and High Performance Computing
    Jiyong Yu, Lucas Hsiung, Mohamad El Hajj, Christopher W. Fletcher
    Appears in the Proceedings of the Internet Society Network and Distributed System Security Symposium (NDSS), 2019
    Distinguished Paper Finalist
    CSAW Applied Research Competition Finalist
    IEEE Micro Top Picks 2020
    [paper] [conference talk] [open-source release

  • Attack Directories, Not Caches: Side Channel Attacks in a Non-Inclusive World
    Mengjia Yan, Read Sprabery, Bhargava Gopireddy, Christopher W. Fletcher, Roy Campbell, Josep Torrellas
    Appears in the Proceedings of the IEEE Symposium on Security and Privacy (Oakland/SP), 2019
    [paper] [conference talk

  • InvisiSpec: Making Speculative Execution Invisible in the Cache Hierarchy
    Mengjia Yan, Jiho Choi, Dimitrios Skarlatos, Adam Morrison, Christopher W. Fletcher, Josep Torrellas
    Appears in the Proceedings of the ACM/IEEE International Symposium on Microarchitecture (MICRO), 2018
    IEEE Micro Top Picks 2019 Honorable Mention
    [paper] [lightning talk] [corrigendum] [corrected paper] [open-source release

  • Morph: Flexible Acceleration for 3D CNN-based Video Understanding
    Kartik Hegde, Rohit Agrawal, Yulun Yao, Christopher W. Fletcher
    Appears in the Proceedings of the ACM/IEEE International Symposium on Microarchitecture (MICRO), 2018
    [paper

  • UCNN: Exploiting Computational Reuse in Deep Neural Networks via Weight Repetition
    Kartik Hegde, Jiyong Yu, Rohit Agrawal, Mengjia Yan, Michael Pellauer, Christopher W. Fletcher
    Appears in the Proceedings of the ACM/IEEE International Symposium on Computer Architecture (ISCA), 2018
    [paper] [lightning talk

  • Path ORAM: An Extremely Simple Oblivious RAM Protocol
    Emil Stefanov, Marten van Dijk, Elaine Shi, T-H Hubert Chan, Christopher W. Fletcher, Ling Ren, Xiangyao Yu, Srinivas Devadas
    Appears in the Journal of the ACM (JACM), 2018
    [paper

  • ZeroTrace: Oblivious Memory Primitives from Intel SGX
    Sajin Sasy, Sergey Gorbunov, Christopher W. Fletcher
    Appears in the Proceedings of the Internet Society Network and Distributed System Security Symposium (NDSS), 2018
    [paper] [open-source release

  • Design and Implementation of the Ascend Secure Processor
    Ling Ren, Christopher W. Fletcher, Albert Kwon; Marten van Dijk; Srinivas Devadas
    Appears in the IEEE Transactions on Dependable and Secure Computing (TDSC), 2017
    [paper

  • Asymptotically tight bounds for composing ORAM with PIR
    Kartik Nayak, Ling Ren, Christopher W. Fletcher, Ittai Abraham, Benny Pinkas
    Appears in the Proceedings of the IACR International Conference on Practice and Theory of Public-Key Cryptography (PKC), 2017
    [paper

  • HOP: Hardware makes Obfuscation Practical
    Kartik Nayak, Christopher W. Fletcher, Ling Ren, Nishanth Chandran, Satya Lokam, Elaine Shi, Vipul Goyal
    Appears in the Proceedings of the Internet Society Network and Distributed System Security Symposium (NDSS), 2017
    [paper] [open-source release

  • Onion ORAM: A Constant Bandwidth Blowup Oblivious RAM
    Srinivas Devadas, Marten van Dijk, Christopher W. Fletcher*, Ling Ren*, Elaine Shi, Daniel Wichs (*: Co-lead authors.)
    Appears in the Proceedings of the IACR Theory of Cryptography Conference (TCC), 2016
    [paper] [conference talk

  • Constants Count: Practical Improvements to Oblivious RAM
    Ling Ren, Christopher W. Fletcher, Albert Kwon, Emil Stefanov, Elaine Shi, Marten van Dijk, Srinivas Devadas
    Appears in the Proceedings of the USENIX Security Symposium (Security), 2015
    [paper

  • PrORAM: Dynamic Prefetcher for Oblivious RAM
    Xiangyao Yu, Syed Kamran Haider, Ling Ren, Christopher W. Fletcher, Albert Kwon, Marten van Dijk, Srinivas Devadas
    Appears in the Proceedings of the ACM/IEEE International Symposium on Computer Architecture (ISCA), 2015
    [paper

  • A Low-Latency, Low-Area Hardware Oblivious RAM Controller
    Christopher W. Fletcher, Ling Ren, Albert Kwon, Marten van Dijk, Emil Stefanov, Dimitrios Serpanos, Srinivas Devadas
    Appears in the Proceedings of the IEEE International Symposium On Field-Programmable Custom Computing Machines (FCCM), 2015
    [paper] [open-source release

  • Freecursive ORAM: [Nearly] Free Recursion and Integrity Verification for Position-based Oblivious RAM
    Christopher W. Fletcher, Ling Ren, Albert Kwon, Marten van Dijk, Srinivas Devadas
    Appears in the Proceedings of the ACM Architectural Support for Programming Languages and Operating Systems (ASPLOS), 2015
    [paper

  • Suppressing the Oblivious RAM Timing Channel While Making Information Leakage and Program Efficiency Trade-offs
    Christopher W. Fletcher, Ling Ren, Xiangyao Yu, Marten van Dijk, Omer Khan, Srinivas Devadas
    Appears in the Proceedings of the IEEE International Symposium on High-Performance Computer Architecture (HPCA), 2014
    [paper

  • Path ORAM: An Extremely Simple Oblivious RAM Protocol
    Emil Stefanov, Marten van Dijk, Elaine Shi, Christopher W. Fletcher, Ling Ren, Xiangyao Yu, Srinivas Devadas
    Appears in the Proceedings of the ACM Conference on Computer and Communications Security (CCS), 2013
    Best Student Paper Award
    Top Picks in Hardware & Embedded Security 2018
    Test of Time Award
    [paper

  • Generalized External Interaction with Tamper-Resistant Hardware with Bounded Information Leakage
    Xiangyao Yu, Christopher W. Fletcher, Ling Ren, Marten van Dijk, Srinivas Devadas
    Appears in the Proceedings of the ACM Cloud Computing Security Workshop (CCSW), 2013
    [paper

  • A Framework to Accelerate Sequential Programs on Homogeneous Multicores
    Christopher W. Fletcher, Rachael Harding, Omer Khan, Srinivas Devadas
    Appears in the Proceedings of the IFIP/IEEE International Conference on Very Large Scale Integration (VLSI-SOC), 2013
    [paper

  • Integrity Verification for Path Oblivious-RAM
    Ling Ren, Christopher W. Fletcher, Xiangyao Yu, Marten van Dijk, Srinivas Devadas
    Appears in the Proceedings of the IEEE High Performance Extreme Computing Virtual Conference (HPEC), 2013
    [paper

  • Design Space Exploration and Optimization of Path Oblivious RAM in Secure Processors
    Ling Ren, Xiangyao Yu, Christopher W. Fletcher, Marten van Dijk, Srinivas Devadas
    Appears in the Proceedings of the ACM/IEEE International Symposium on Computer Architecture (ISCA), 2013
    [paper

  • Towards an Interpreter for Efficient Encrypted Computation
    Christopher W. Fletcher, Marten van Dijk, Srinivas Devadas
    Appears in the Proceedings of the ACM Cloud Computing Security Workshop (CCSW), 2012
    [paper

  • A Secure Processor Architecture for Encrypted Computation on Untrusted Programs
    Christopher W. Fletcher, Marten van Dijk, Srinivas Devadas
    Appears in the Proceedings of the ACM Workshop on Scalable Trusted Computing (STC), 2012
    [paper

  • HORNET: a cycle-level multicore simulator
    Pengju Ren, Mieszko Lis, Myong Hyon Cho, Keun Sup Shim, Christopher W. Fletcher, Omer Khan, Nanning Zheng, Srinivas Devadas
    Appears in the IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems (TCAD), 2012
    [paper

  • A Low-overhead Dynamic Optimization Framework on Multicores (short paper)
    Christopher W. Fletcher, Rachael Harding, Omer Khan, Srinivas Devadas
    Appears in the Proceedings of the International Conference on Parallel Architectures and Compilation Techniques (PACT), 2012
    [paper

  • Exploring Many-core Design Templates for FPGAs and ASICs
    Ilia Lebedev, Christopher W. Fletcher, Shaoyi Cheng, James Martin, Austin Doupnik, Daniel Burke, Mingjie Lin, John Wawrzynek
    Appears in the Proceedings of the International Journal of Reconfigurable Computing (IJRC), 2012
    [paper

  • Scalable Accurate Multicore Simulation in the 1000 core era
    Mieszko Lis, Pengju Ren, Myong Hyon Cho, Keun Sup Shim, Christopher W. Fletcher, Omer Khan, Srinivas Devadas
    Appears in the Proceedings of the International Symposium on Performance Analysis of Systems and Software (ISPASS), 2011
    [paper

  • Brief Announcement: Distributed Shared Memory based on Computation Migration (short paper)
    Mieszko Lis, Keun Sup Shim, Myong Hyon Cho, Christopher W. Fletcher, Michel Kinsy, Ilia Lebedev, Omer Khan, Srinivas Devadas
    Appears in the Proceedings of the ACM Symposium on Parallelism in Algorithms and Architectures (SPAA), 2011
    [paper

  • Bridging the GPGPU-FPGA Efficiency Gap (short paper)
    Christopher W. Fletcher, Ilia Lebedev, Narges B. Asadi, Daniel R. Burke, John Wawrzynek
    Appears in the Proceedings of the International Symposium on Field-Programmable Gate Arrays (FPGA), 2011
    [paper

  • MARC: A Many-Core Approach to Reconfigurable Computing
    Ilia Lebedev, Shaoyi Cheng, Austin Doupnik, James Martin, Christopher W. Fletcher, Daniel Burke, Mingjie Lin, John Wawrzynek
    Appears in the Proceedings of the International Conference on Reconfigurable Computing and FPGAs (ReConFig), 2010
    [paper

  • ParaLearn: A Massively Parallel, Scalable System for Learning Interaction Networks on FPGAs
    Narges B. Asadi*, Christopher W. Fletcher*, Greg Gibeling, Karen Sachs, Eric Glass, Daniel Burke, Zoey Zhou, John Wawrzynek, Wing H. Wong, Garry P. Nolan (*: Co-lead authors.)
    Appears in the Proceedings of the International Conference on Supercomputing (ICS), 2010
    Best Student Paper Award
    [paper] [slides

Theses

  • Oblivious RAM: From Theory to Practice
    Christopher W. Fletcher
    PhD thesis
    George M. Sprowls Award for outstanding PhD thesis in CS at MIT
    [thesis

  • Ascend: An Architecture for Performing Secure Computation on Encrypted Data
    Christopher W. Fletcher
    SM thesis
    [thesis

Patents

  • Technique for secure computation
    Srinivas Devadas, Christopher W. Fletcher, Marten Van Dijk
    Patent No. 8909967
    (Note: there is currently a bug where only Marten is listed as inventor. The lawyers are fixing it...)

Funding

We thank NSF, DARPA, Intel and Google for their generous support!