Ling Ren

I am an assistant professor in the Computer Science Department at University of Illinois, Urbana-Champaign. Prior to joining UIUC, I received my PhD from MIT and worked as a postdoctoral researcher at VMware Research Group.

Email: renling at illinois dot edu.


CS598LR Consensus Algorithms, fall 2019.

6.046J Design and Analysis of Algorithms, fall 2017.


I work on applied cryptography, computer security and distributed algorithms. I am generally interested in designing algorithms that are both practical and provably secure. As a result, my research has been as theoretical as better asymptotic efficiency, and as practical as taping out a processor. Currently, I am focusing on fault tolerant consensus (aka blockchain), proof of space/time/bandwidth, and homomorphic encryption. My past work includes oblivious RAM and secure hardware.

Selected Publications

For a full list, see my Google Scholar page.

Ling Ren. Analysis of Nakamoto Consensus. preprint.

Ittai Abraham, Dahlia Malkhi, Kartik Nayak, Ling Ren, Maofen Yin. Sync HotStuff: Simple and Practical Synchronous State Machine Replication, S&P 2020.

Dahlia Malkhi, Kartik Nayak and Ling Ren. Flexible Byzantine Fault Tolerance. CCS 2019.

Hao Chen , Ilaria Chillotti , and Ling Ren. Onion Ring ORAM: Efficient Constant Bandwidth Oblivious RAM from (Leveled) TFHE. CCS 2019.

Ittai Abraham, T-H. Hubert Chan, Danny Dolev, Kartik Nayak, Rafael Pass, Ling Ren, Elaine Shi. Communication Complexity of Byzantine Agreement, Revisited. PODC 2019.

Gilad Asharov, T-H. Hubert Chan, Kartik Nayak, Rafael Pass, Ling Ren and Elaine Shi. Locality-Preserving Oblivious RAM. Eurocrypt, 2019.

Ittai Abraham, Srinivas Devadas, Danny Dolev, Kartik Nayak, and Ling Ren. Synchronous Byzantine Agreement with Expected O(1) Rounds, Expected O(n^2) Communication, and Optimal Resilience. FC 2019.

Jeremiah Blocki, Ling Ren, and Samson Zhou. Bandwidth-Hard Functions: Reductions and Lower Bounds. CCS 2018.

Ittai Abraham, Dahlia Malkhi, Kartik Nayak, Ling Ren, and Alexander Spiegelman. Solida: A Blockchain Protocol Based on Reconfigurable Byzantine Consensus. OPODIS 2017.

Srinivas Devadas, Ling Ren and Hanshen Xiao. On Iterative Collision Search for LPN and Subset Sum. TCC 2017.

Ling Ren and Srinivas Devadas. Bandwidth Hard Functions for ASIC Resistance. TCC 2017.

Ling Ren, Christopher Fletcher, Albert Kwon, Marten van Dijk, and Srinivas Devadas. Design and Implementation of the Ascend Secure Processor. TDSC 2017. Code

Ling Ren, Srinivas Devadas. Proof of Space from Stacked Expanders. TCC 2016.

Srinivas Devadas, Marten van Dijk, Christopher Fletcher, Ling Ren, Elaine Shi, and Daniel Wichs. Onion ORAM: A Constant Bandwidth Blowup Oblivious RAM. TCC 2016.

Ling Ren, Christopher Fletcher, Albert Kwon, Emil Stefanov, Elaine Shi, Marten van Dijk, and Srinivas Devadas. Constants Count: Practical Improvements to Oblivious RAM. USENIX Security, 2015.

Christopher Fletcher, Ling Ren, Albert Kwon, Marten van Dijk, and Srinivas Devadas. Freecursive ORAM: [Nearly] Free Recursion and Integrity Verification for Position-based ORAMs. ASPLOS 2015.

Emil Stefanov, Marten van Dijk, Elaine Shi, Christopher Fletcher, Ling Ren, Xiangyao Yu, and Srinivas Devadas. Path ORAM: An Extremely Simple Oblivious RAM Protocol. CCS 2013. Best Student Paper Award.

Ling Ren, Xiangyao Yu, Christopher Fletcher, Marten Van Dijk, and Srinivas Devadas. Design Space Exploration and Optimization of Path Oblivious RAM in Secure Processors. ISCA 2013.