Jeremiah Blocki @Purdue (Publications)

Password Hashing

Bandwidth-Hard Functions: Reductions and Lower Bounds. with Ling Ren and Samson Zhou. [Full Version]
Sustained Space Complexity. with Joel Alwen and Krzysztof Pietrzak. EUROCRYPT 2018 [Full Version]
On the Economics of Offline Password Cracking. with Ben Harsha and Samson Zhou. 39th IEEE Symposium on Security & Privacy (S&P 2018). [Paper]
On the Computational Complexity of Minimal Cumulative Cost Graph Pebbling. with Samson Zhou. Financial Crypto 2018 . [arXiv]
Just In Time Hashing. with Ben Harsha. 3rd IEEE European Symposium on Security and Privacy (EURO S&P 2018). [Full Version]
Practical Graphs for Optimal Side-Channel Resistant Memory-Hard Functions. with Joel Alwen and Ben Harsha. CCS 2017. Full Version
On the Depth-Robustness and Cumulative Pebbling Cost of Argon2i. with Samson Zhou. TCC 2017. [Full Version]
Depth-Robust Graphs and Their Cumulative Memory Complexity. with Joel Alwen and Krzysztof Pietrzak. EUROCRYPT 2017. [Full Version]
Towards Practical Attacks on Argon2i and Balloon Hashing. with Joel Alwen. EuroS&P 2017. [Full Version]
Efficiently Computing Data Independent Memory Hard Functions. with Joel Alwen. CRYPTO 2016. [Full Version]
Designing Proof of Human-work Puzzles for Cryptocurrency and Beyond. with Hong-Shen Zhou. TCC 2016-B. [Full Version]
CASH: A Cost Asymmetric Secure Hash Algorithm for Optimal Password Protection. with Anupam Datta. CSF 2016. [Full Version]
Client-CASH: Protecting Master Passwords against Offline Attacks. with Anirudh Sridhar. AsiaCCS 2016. [Full Version]

Applications of Depth-Robust Graphs

Relaxed Locally Correctable Codes in Computationally Bounded Channels with Venkata Gandikota, Elena Grigorescu and Samson Zhou. [Full Version]

Usable and Secure Human Authentication

Towards Human Computable Passwords. with Manuel Blum, Anupam Datta and Santosh Vempala. ITCS 2017. [arXiv] [Password Cracking Challenge]
Spaced Repetition and Mnemonics Enable Recall of Multiple Strong Passwords. with Saranga Komanduri, Lorrie Cranor and Anupam Datta. NDSS 2015. [Full Version]
Press: ZDNet, Kapersky
GOTCHA Password Hackers! with Manuel Blum and Anupam Datta. AISec 2013. [Full Version] [GOTCHA Challenge]
Press: ArsTechnica, Slashdot, The Tartan and an inaccurate article from MIT Technology Review
Naturally Rehearsing Passwords. with Manuel Blum and Anupam Datta. ASIACRYPT 2013. [Full Version]
Press: Scientific American, ScienceDaily, CMU
Optimizing Password Composition Policies. with Saranga Komanduri, Ariel Procaccia and Or Sheffet. EC 2013. [Full Version]

Privacy Preserving Data Analysis

Locally Differentially Private Protocols for Frequency Estimation. with Tianhao Wang, Ninghui Li and Somesh Jha. USENIX 2017. Full Version
Differentially Private Password Frequency Lists: Or, How to release statistics from 70 million passwords (on purpose). with Anupam Datta and Joseph Bonneau. NDSS 2016. [Full Version]
Press: CMU, Science Newsline
Differentially Private Data Analysis of Social Networks via Restricted Sensitivity. with Avrim Blum, Anupam Datta and Or Sheffet. ITCS 2013. [Full Version]
The Johnson-Lindenstrausss Transform Itself Preserves Differential Privacy. with Avrim Blum, Anupam Datta and Or Sheffet. FOCS 2012. [Full Version]
Resolving the Complexity of Some Data Privacy Problems. with Ryan Williams. ICALP 2010. [Full Version]

Game Theory and Security

Audit Games with Multiple Defender Resources. with Nicolas Christin, Anupam Datta, Ariel Procaccia and Arunesh Sinha. AAAI 2015. [Full Version]
Audit Games. with Nicolas Christin, Anupam Datta, Ariel Procaccia and Arunesh Sinha. IJCAI 2013. [Full Version]
Adaptive Regret Minimization in Bounded-Memory Games. with Nicolas Christin, Anupam Datta and Arunesh Sinha. GameSec 2013. [Invited Paper] [Full Version]
Audit Mechanisms for Privacy Protection in Healthcare Environments. with Nicolas Christin, Anupam Datta and Arunesh Sinha. HealthSec 2011. [position paper]
Regret Minimizing Audits: A Learning-Theoretic Basis for Privacy Protection. with Nicolas Christin, Anupam Datta and Arunesh Sinha. CSF 2011. [Full Version]