Prabhanjan Ananth
Assistant Professor (Glenn and Susanne Culler Chair)
1119 Harold Frank Hall,
Department of Computer Science,
University of California, Santa Barbara
Email: prabhanjan at cs ucsb edu
I got my Ph.D. (2013 - 2017) at UCLA under the supervision of Amit Sahai and Rafail Ostrovsky. I spent two years (2017 - 2019) as a postdoc at CSAIL, MIT under the supervision of Vinod Vaikuntanathan.
I'm broadly interested in all aspects of cryptography and specifically, I'm interested in (post-)quantum cryptography.
News: Thanks to the NSF for the Career award.
Teaching
CS 138: Automata and Formal Languages (Winter 2021, Fall 2022, Fall 2023, Fall 2024)
CS 178: Introduction to Cryptography (Spring 2021, Fall 2021, Spring 2022, Winter 2023, Winter 2025)
Graduate
CS 292G: Graduate Course in Cryptography (Winter 2020)
CS 292G: Topics in Quantum Cryptography (Fall 2020, Winter 2022)
CS 292G: Graduate Course in Quantum Computing (Spring 2023, Spring 2024, Spring 2025)
Advising
Ph.D.:
Past mentored undergraduate students:
Siyuan Chen (Tsinghua University)
Zihan Hu (BS, Tsinghua University -> joining Ph.D. program at Carnegie Mellon University)
Manu Kondapaneni (BS, UCSB -> Ph.D. student at Northeastern University)
Aditya Gulati (BS, IIT Kanpur -> Ph.D. student at UCSB)
Zackary Glazewski (BS, UCSB)
Rowan-James Tran (BS, UCSB)
Aashay Parab (BS, UCSB)
Anika Arora (BS, UCSB)
Mohit Sharma (IIT Roorkee)
Philip Axelrod (BS, UCSB)
Past mentored graduate students:
Saikumar Yadugiri (MS, UCSB -> Ph.D. student at University of Wisconsin Madison)
Past graduate student visitors:
Amit Behera (Ben-Gurion University)
Alexander Poremba (Ph.D., Caltech)
Luowen Qian (Ph.D. student at Boston University)
Rolando La Placa (Ph.D., MIT): thesis
Publications
(Note: Only published research papers with proceedings are numbered below.)
2024
(with Aditya Gulati, Fatih Kaleoglu, Yao-Ting Lin)
EUROCRYPT 2024
50. Pseudorandom Strings from Pseudorandom Quantum States
(with Yao-Ting Lin, Henry Yuen)
ITCS 2024
49. Provable Robust Watermarking for AI-Generated Text
(with Xuandong Zhao, Lei Li, Yu-Xiang Wang)
ICLR 2024
48. ORTOA: One Round Trip Oblivious Access
(with Sujaya Maiyya, Yuval Steinhart, Divyakant Agrawal, Amr El Abbadi)
EDBT 2024
NIZKs with Maliciously Chosen CRS: Subversion Advice-ZK and Accountable Soundness
(with Gilad Asharov, Vipul Goyal, Hadar Kaner, Pratik Soni, Brent Waters)
A Note on the Common Haar State Model
(with Aditya Gulati and Yao-Ting Lin)
2023
47. Revocable Cryptography from Learning with Errors
(with Alexander Poremba, Vinod Vaikuntanathan)
TCC 2023
46. On the (Im)Plausibility of Public-Key Quantum Money from Collision-Resistant Hash Functions
(with Zihan Hu, Henry Yuen)
ASIACRYPT 2023
45. Cloning Games: A General Framework for Unclonable Primitives
(with Fatih Kaleoglu, Qipeng Liu)
CRYPTO 2023
QCRYPT 2023
Pseudorandom Quantum States, Revisited: New Properties, Variants, Constructions, and Cryptographic Applications
(with Aditya Gulati, Luowen Qian and Henry Yuen)
QIP 2023 (short plenary talk)
On the Feasibility of Unclonable Encryption, and More
(with Fatih Kaleoglu, Xingjian Li, Qipeng Liu, Mark Zhandry)
QIP 2023 (contributed talk)
A Modular Approach to Unclonable Cryptography
(with Amit Behera)
2022
44. Pseudorandom (Function-Like) Quantum State Generators: New Definitions and Applications
(with Aditya Gulati, Luowen Qian and Henry Yuen)
TCC 2022
QCRYPT 2022
43. Collusion-Resistant Functional Encryption for RAMs
(with Kai-Min Chung, Xiong Fan, Luowen Qian)
ASIACRYPT 2022
42. Cryptography from Pseudorandom Quantum States
(with Luowen Qian, Henry Yuen)
CRYPTO 2022
QCRYPT 2022
[Twitter summary by Henry]
41. On the Feasibility of Unclonable Encryption, and More
(with Fatih Kaleoglu, Xingjian Li, Qipeng Liu, Mark Zhandry)
CRYPTO 2022
40. Pre-Constrained Encryption
(with Abhishek Jain, Zhengzhong Jin, Giulio Malavolta)
ITCS 2022
Post-Quantum Zero-Knowledge with Space-Bounded Simulation
(with Alex B. Grilo)
A Note on Copy-Protection from Random Oracles
(with Fatih Kaleoglu)
Quantum Cryptography Workshop 2022
2021
39. Unclonable Encryption, Revisited
(with Fatih Kaleoglu)
TCC 2021
38. On the Concurrent Composition of Quantum Zero-Knowledge
(with Kai-Min Chung, Rolando L. La Placa)
CRYPTO 2021
37. Secure Software Leasing
(with Rolando L. La Placa)
EUROCRYPT 2021
QIP 2021 (joint short plenary talk with ABDS)
[Shtetl-Optimized]
36. Towards Accountability in CRS Generation
(with Gilad Asharov, Hila Dahari, Vipul Goyal)
EUROCRYPT 2021
35. Unbounded MPC from Learning with Errors
(with Abhishek Jain, Zhengzhong Jin, Giulio Malavolta)
EUROCRYPT 2021
2020
34. Secure Quantum Extraction Protocols (with Rolando L. La Placa)
TCC 2020
33. Multi-key Fully-Homomorphic Encryption in the Plain Model
(with Abhishek Jain, Zhengzhong Jin and Giulio Malavolta) [subsumes AJJ]
TCC 2020
32. Towards Efficiency Preserving Round-Compression Compilers in MPC
(with Arka Rai Choudhuri, Aarushi Goel and Abhishek Jain)
ASIACRYPT 2020
2019
31. Optimal Bounded-Collusion Secure Functional Encryption
(with Vinod Vaikuntanathan)
TCC 2019
30. Fully Homomorphic NIZK and NIWI Proofs
(with Apoorvaa Deshpande, Yael Tauman Kalai and Anna Lysyanskaya)
TCC 2019
29. From FE Combiners to Secure MPC and Back (with Saikrishna Badrinarayanan, Aayush Jain, Nathan Manohar and Amit Sahai)
TCC 2019
28. Towards Attribute-Based Encryption from LWE: Sublinear Decryption and More
(with Xiong Fan and Elaine Shi)
ASIACRYPT 2019
27. Indistinguishability Obfuscation Without Multilinear Maps: New Paradigms via Low Degree Weak Pseudorandomness and Security Amplification
(with Aayush Jain, Huijia Lin, Christian Matt and Amit Sahai; merge of [AJS18] and [LM18])
CRYPTO 2019
26. Two Round Information-Theoretic MPC with Malicious Security
(with Arka Rai Choudhuri, Aarushi Goel and Abhishek Jain)
EURORYPT 2019
2018
25. Succinct Garbling Schemes from Functional Encryption through a Local Simulation Paradigm (with Alex Lombardi)
TCC 2018
24. Private Circuits: A Modular Approach
(with Yuval Ishai and Amit Sahai)
CRYPTO 2018
23. Round-Optimal Secure Multiparty Computation with Honest Majority
(with Arka Rai Choudhuri, Aarushi Goel and Abhishek Jain)
CRYPTO 2018
2017
22. On Secure Two-Party Computation in Three Rounds (with Abhishek Jain)
TCC 2017
21. A New Approach to Round-Optimal Secure Multiparty Computation (with Arka Rai Choudhuri, Aarushi Goel and Abhishek Jain)
CRYPTO 2017
20. Indistinguishability Obfuscation for Turing Machines: Constant Overhead and Amortization (with Abhishek Jain and Amit Sahai)
CRYPTO 2017
19. Projective Arithmetic Functional Encryption and Indistinguishability Obfuscation From Degree-5 Multilinear Maps
(with Amit Sahai)
EUROCRYPT 2017
18. Cryptography with Updates
(with Aloni Cohen and Abhishek Jain)
EUROCRYPT 2017
17. Patchable Indistinguishability Obfuscation: iO for Evolving Software (with Abhishek Jain and Amit Sahai)
EUROCRYPT 2017
16. Robust Transforming Combiners from Indistinguishability Obfuscation to Functional Encryption
(with Aayush Jain and Amit Sahai)
EUROCRYPT 2017
2016
15. Delegating RAM Computations with Adaptive Soundness and Privacy (with Yu-Chi Chen, Kai-Min Chung, Huijia Lin and Wei-Kai Lin)
TCC 2016-B
14. Universal Obfuscation and Witness Encryption: Boosting Correctness and Combining Security
(with Aayush Jain, Moni Naor, Amit Sahai and Eylon Yogev)
CRYPTO 2016
13. Functional Encryption for Turing Machines
(with Amit Sahai)
TCC 2016-A
2015
12. Indistinguishability Obfuscation from Compact Functional Encryption
(with Abhishek Jain)
CRYPTO 2015
11. From Selective to Adaptive Security in Functional Encryption
(with Zvika Brakerski, Gil Segev and Vinod Vaikuntanathan)
CRYPTO 2015
Indistinguishability Obfuscation from Functional Encryption for Simple Functions
(with Abhishek Jain and Amit Sahai)
2014
10. Optimizing Obfuscation: Avoiding Barrington’s Theorem (with Divya Gupta, Yuval Ishai and Amit Sahai)
ACM CCS 2014
9. Interactive Proofs under Continual Memory Leakage
(with Vipul Goyal and Omkant Pandey)
CRYPTO 2014
8. Achieving Privacy in Verifiable Computation with Multiple Servers; Without FHE and without Pre-processing
(with Nishanth Chandran, Vipul Goyal, Bhavana Kanukurthi and Rafail Ostrovsky)
PKC 2014
7. Lower Bounds in the Hardware Token Model
(with Shashank Agrawal, Vipul Goyal, Manoj Prabhakaran and Alon Rosen)
TCC 2014
2013
6. On the (In)security of Fischlin's Paradigm (with Raghav Bhaskar, Vipul Goyal and Vanishree Rao)
TCC 2013
5. Non Observability In the Random Oracle Model
(with Raghav Bhaskar)
ProvSec 2013
Differing-Inputs Obfuscation and Applications
(with Dan Boneh, Sanjam Garg, Amit Sahai and Mark Zhandry)
2012
4. Complexity of Grobner Basis Detection and Border Basis Detection (with Ambedkar Dukkipati)Journal of Theoretical Computer Science 2012
3. An Algebraic Characterization of Rainbow Connectivity
(with Ambedkar Dukkipati)
CASC 2012
2011
2. Rainbow Connectivity: Hardness and Tractability
(with Meghana Nasre and Kanthi K. Sarpatwar)
FSTTCS 2011
1. Border Basis Detection is NP-Complete (with Ambedkar Dukkipati)
ISSAC 2011
Program Committees
PKC 2018
ASIACRYPT 2018
TCC 2020
PKC 2022
CRYPTO 2022
Quantum Cryptography workshop (co-organized with Asiacrypt 2022)
EUROCRYPT 2023
ITC 2023
TCC 2023
STACS 2024
Editorial Board, IACR Communications in Cryptography (2024)
TCC 2024
ASIACRYPT 2024 (area chair)
ArcticCrypt 2025
Misc
For visitors at UCSB: There are many options near UCSB for staying. However, many of these options are quite expensive. There are a couple of (relatively) cheaper options, apart from those you can find on AirBnB:
There are many nice places to see in and around Santa Barbara: botanical garden, Mission Church, Santa Barbara zoo, hikes and, of course, beaches.
For students at UCSB:
If you are interested in taking my course but have not yet enrolled: please meet me right after the first lecture. If you can't make it the first lecture, meet me after the second lecture. I'm not good with emails, so this is the best way to reach me.
If you have taken one of my courses and interested in receiving a letter of recommendation from me (for BS/MS or Masters): I typically only write letters for students who have secure an A+ in my course and in some rare cases, A. If you have never interacted with me during/after the lectures, it is unlikely that I'll write a letter for you.
If you are interested in doing research: as an undergraduate student, it can be challenging to pursue research. Before deciding on the research area, it is a good first step to understand the research process to make sure that you are comfortable with it. Here are some useful articles:
Advice to a beginning graduate student
If you are an undergraduate student interested in pursuing research with me: you should have taken courses CS 138 and CS 178 before reaching out to me. You should have a strong mathematical background and should be comfortable with mathematical proofs. In some rare cases, I'll make an exception.