Research

An increasing number of businesses and individuals are adopting cloud computing as their main computing infrastructure. In fact, remote data storage (e.g., Amazon S3) and outsourcing of computation (e.g., Google docs) have become a major everyday phenomenon.

Although cloud computing provides great services to costumers, it does trigger many security concerns: Users' data is now stored at untrusted, geographically dispersed, servers and possibly untrusted applications might execute on it. Therefore users lose control of their data and programs, which could be modified or accessed by unauthorized entities. For example, sensitive information could be leaked or tampered with due to malicious or buggy cloud software, leading to undesirable situations.

My research aims at alleviating these concerns of the community, by providing integrity and privacy guarantees for cloud services, in an efficient way. Specifically it offers several types of cryptographic assurances, so that remote data and computations cannot be altered (without being detected) and data managed by cloud applications cannot leak.

Apart from research on cloud computing security, I enjoy working on cryptography, data structures and algorithm design. In the past, I spent some time working on graph algorithms and graph drawing.

Publications

	conferences
	Ahmed Kosba, Dimitrios Papadopoulos, Charalampos Papamanthou, and Dawn Song. MIRAGE: Succinct Arguments for Randomized Algorithms with Applications to Universal zk-SNARKs . In Proc. USENIX SECURITY Symposium (USENIX SECURITY), Boston MA, USA, 2020. Ioannis Demertzis, Dimitrios Papadopoulos, Charalampos Papamanthou, and Saurabh Shintre. SEAL: Attack Mitigation for Encrypted Databases via Adjustable Leakage. In Proc. USENIX SECURITY Symposium (USENIX SECURITY), Boston MA, USA, 2020. Ioannis Demertzis, Javad Ghareh Chamani, Dimitrios Papadopoulos, and Charalampos Papamanthou. Dynamic Searchable Encryption with Small Client Storage. In Proc. Int. Network and Distributed System Security Symposium (NDSS), San Diego CA, USA, 2020. Evgenios Kornaropoulos, Charalampos Papamanthou, and Roberto Tamassia. The State of the Uniform: Attacks on Encrypted Databases Beyond the Uniform Query Distribution. In Proc. Int. Symposium on Security and Privacy (SSP), San Francisco CA, USA, 2020. Alin Tomescu, Vivek Bhupatiraju, Dimitrios Papadopoulos, Charalampos Papamanthou, Nikos Triandopoulos, and Srinivas Devadas. Transparency Logs via Append-only Authenticated Dictionaries. In Proc. Int. ACM Conference on Computer and Communications Security (CCS), London, UK, 2019. Tiancheng Xie, Jiaheng Zhang, Yupeng Zhang, Charalampos Papamanthou, and Dawn Song. Libra: Succinct Zero-Knowledge Proofs with Optimal Prover Computation. In Proc. Int. Cryptology Conference (CRYPTO), Santa Barbara CA, USA, 2019. Evgenios Kornaropoulos, Charalampos Papamanthou, and Roberto Tamassia. Data Recovery on Encrypted Databases With k-Nearest Neighbor Query Leakage. In Proc. Int. Symposium on Security and Privacy (SSP), San Francisco CA, USA, 2019. Javad Ghareh Chamani, Dimitrios Papadopoulos, Charalampos Papamanthou, and Rasool Jalili. New Constructions for Forward and Backward Private Symmetric Searchable Encryption. In Proc. Int. ACM Conference on Computer and Communications Security (CCS), Toronto, Canada, 2018. Ioannis Demertzis, Dimitrios Papadopoulos, and Charalampos Papamanthou. Searchable Encryption with Optimal Locality: Achieving Sublogarithmic Read Efficiency. In Proc. Int. Cryptology Conference (CRYPTO), Santa Barbara CA, USA, 2018. Ahmed Kosba, Charalampos Papamanthou, and Elaine Shi. xJsnark: A Framework for Efficient Verifiable Computation. In Proc. Int. Symposium on Security and Privacy (SSP), San Francisco CA, USA, 2018. Yupeng Zhang, Daniel Genkin, Jonathan Katz, Dimitrios Papadopoulos, and Charalampos Papamanthou. vRAM: Faster Verifiable RAM With Program-Independent Preprocessing. In Proc. Int. Symposium on Security and Privacy (SSP), San Francisco CA, USA, 2018. Lluis Vilanova, Casen Hunger, Charalampos Papamanthou, Yoav Etsion, and Mohit Tiwari. DATS: Refactoring Access Control Out of Web Applications. In Proc. Int. ACM Conference on Architectural Support for Programming Languages and Operating Systems (ASPLOS), Williamsburg VA, USA, 2018. Mohammad Etemad, Alptekin Küpçü, Charalampos Papamanthou and David Evans. Efficient Dynamic Searchable Encryption with Forward Privacy. In Proc. Privacy Enhancing Technologies (PETS), Barcelona, Spain, 2018. Wei Bai, Ciara Lynton, Michelle L. Mazurek, and Charalampos Papamanthou. Understanding User Tradeoffs for Search in Encrypted Communication. In Proc. European Symposium on Security and Privacy (EUROSSP), London, UK, 2018. Ioannis Demertzis, Rajdeep Talapatra, and Charalampos Papamanthou. Efficient Searchable Encryption Through Compression. In Proc. Very Large Databases (VLDB), Rio de Janeiro, Brasil, 2018. Yupeng Zhang, Daniel Genkin, Jonathan Katz, Dimitrios Papadopoulos, and Charalampos Papamanthou. vSQL: Verifying General SQL Queries over Dynamic Outsourced Databases. In Proc. Int. Symposium on Security and Privacy (SSP), San Jose CA, USA, 2017. Ioannis Demertzis and Charalampos Papamanthou. Fast Searchable Encryption with Tunable Locality. In Proc. ACM Special Interest Group on Management of Data (SIGMOD), Chicago IL, USA, 2017. Yupeng Zhang, Jonathan Katz, and Charalampos Papamanthou. An Expressive (Zero-Knowledge) Set Accumulator. In Proc. European Symposium on Security and Privacy (EUROSSP), Paris, France, 2017. Giuseppe Ateniese, Michael T. Goodrich, Vasilis Lekakis, Charalampos Papamanthou, Evripidis Paraskevas, and Roberto Tamassia. Accountable Storage. In Proc. Applied Cryptography and Network Security (ACNS), Kanazawa, Japan, 2017. Yupeng Zhang, Jonathan Katz, and Charalampos Papamanthou. All Your Queries Are Belong to Us: The Power of File-Injection Attacks on Searchable Encryption. In Proc. USENIX SECURITY Symposium (USENIX SECURITY), Austin TX, USA, 2016. Sanjam Garg, Payman Mohassel, and Charalampos Papamanthou. TWORAM: Efficient oblivious RAM in Two Rounds with Applications to Searchable Encryption. In Proc. Int. Cryptology Conference (CRYPTO), Santa Barbara CA, USA, 2016. Ahmed Kosba, Andrew Miller, Elaine Shi, Zikai Wen and Charalampos Papamanthou. Hawk: The Blockchain Model of Cryptography and Privacy-Preserving Smart Contracts. In Proc. Int. Symposium on Security and Privacy (SSP), San Jose CA, USA, 2016. Dana Dachman-Soded, Chang Liu, Charalampos Papamanthou, Elaine Shi and Uzi Vishkin. Oblivious Network RAM and Leveraging Parallelism to Achieve Obliviousness. In Proc. Int. Conference on the Theory and Application of Cryptology and Information Security (ASIACRYPT), Auckland, New Zealand, 2015. Yupeng Zhang, Jonathan Katz and Charalampos Papamanthou. IntegriDB: Verifiable SQL for Outsourced Databases. In Proc. Int. ACM Conference on Computer and Communications Security (CCS), Denver CO, USA, 2015. Dimitrios Papadopoulos, Charalampos Papamanthou, Roberto Tamassia and Nikos Triandopoulos. Practical Authenticated Pattern Matching with Optimal Proof Size. In Proc. Very Large Databases (VLDB), Kohala Coast HI, USA, 2015. Hubert Chan, Charalampos Papamanthou, and Zhichao Zhao. On the Complexity of the Minimum Independent Set Partition Problem. In Proc. Int. Computing and Combinatorics Conference (COCOON), Beijing, China, 2015. Yi Qian, Yupeng Zhang, Xi Chen and Charalampos Papamanthou. Streaming Authenticated Data Structures: Abstraction and Implementation. In Proc. Int. ACM Cloud Computing Security Workshop (CCSW), Scottsdale AZ, 2014. Yupeng Zhang, Charalampos Papamanthou and Jonathan Katz. ALITHEIA: Towards Practical Verifiable Graph Processing. In Proc. Int. ACM Conference on Computer and Communications Security (CCS), Scottsdale AZ, 2014. Ahmed E. Kosba, Dimitrios Papadopoulos, Charalampos Papamanthou, Mahmoud F. Sayed, Elaine Shi and Nikos Triandopoulos. TRUESET: Faster Verifiable Set Computations. In Proc. USENIX SECURITY Symposium (USENIX SECURITY), San Diego CA, USA, 2014. Emil Stefanov, Charalampos Papamanthou and Elaine Shi. Practical Dynamic Searchable Encryption with Small Leakage. In Proc. Int. Network and Distributed System Security Symposium (NDSS), San Diego CA, USA, 2014. Elaine Shi, Emil Stefanov and Charalampos Papamanthou. Practical Dynamic Proofs of Retrievability. In Proc. Int. ACM Conference on Computer and Communications Security (CCS), Berlin, Germany, 2013. Charalampos Papamanthou, Elaine Shi, Roberto Tamassia and Ke Yi. Streaming Authenticated Data Structures. In Proc. Int. Conference on the Theory and Applications of Cryptographic Techniques (EUROCRYPT), Athens, Greece, 2013. Seny Kamara and Charalampos Papamanthou. Parallel and Dynamic Searchable Symmetric Encryption. In Proc. Int. Financial Cryptography and Data Security Conference (FC), Okinawa, Japan, 2013. Charalampos Papamanthou, Elaine Shi and Roberto Tamassia. Signatures of Correct Computation. In Proc. Int. Theory of Cryptography Conference (TCC), Tokyo, Japan, 2013. Prateek Mittal, Charalampos Papamanthou and Dawn Song. Preserving Link Privacy in Social Network Based Systems. In Proc. Int. Network and Distributed System Security Symposium (NDSS), San Diego CA, USA, 2013. Seny Kamara, Charalampos Papamanthou and Tom Roeder. Dynamic Searchable Symmetric Encryption. In Proc. Int. ACM Conference on Computer and Communications Security (CCS), Raleigh NC, USA, 2012. Michael T. Goodrich, Duy Nguyen, Olga Ohrimenko, Charalampos Papamanthou, Roberto Tamassia, Nikos Triandopoulos, and Cristina Videira Lopes. Efficient Verification of Web-Content Searching Through Authenticated Web Crawlers. In Proc. Very Large Databases (VLDB), Istanbul, Turkey, 2012. Charalampos Papamanthou, Roberto Tamassia, and Nikos Triandopoulos. Optimal Verification of Operations on Dynamic Sets. In Proc. Int. Cryptology Conference (CRYPTO), Santa Barbara CA, USA, 2011. Petros Maniatis, Michael Dietz, and Charalampos Papamanthou. MOMMIE Knows Best: Systematic Optimizations for Verifiable Distributed Algorithms. In Proc. Int. Workshop on Hot Topics in Operating Systems (HotOS), Napa CA, USA, 2011. Charalampos Papamanthou, Roberto Tamassia, and Nikos Triandopoulos. Optimal Authenticated Data Structures with Multilinear Forms. In Proc. Int. Conference on Pairing-Based Cryptography (PAIRING), Ishikawa, Japan, 2010. C. Christopher Erway, Alptekin Küpçü, Charalampos Papamanthou, and Roberto Tamassia. Dynamic Provable Data Possession. In Proc. Int. ACM Conference on Computer and Communications Security (CCS), Chicago IL, USA, 2009. Charalampos Papamanthou, Roberto Tamassia, and Nikos Triandopoulos. Authenticated Hash Tables. In Proc. Int. ACM Conference on Computer and Communications Security (CCS), Alexandria VA, USA, 2008. Alexander Heitzmann, Bernardo Palazzi, Charalampos Papamanthou, and Roberto Tamassia. Efficient Integrity Checking of Untrusted Network Storage. In Proc. Int. ACM CCS Workshop on Storage Security and Survivability (STORAGESS), Alexandria VA, USA, 2008. Alexander Heitzmann, Bernardo Palazzi, Charalampos Papamanthou, and Roberto Tamassia. Effective Visualization of File System Access-Control. In Proc. Int. Workshop on Security Visualization (VIZSEC), Boston MA, USA, 2008. Michael T. Goodrich, Charalampos Papamanthou, Roberto Tamassia, and Nikos Triandopoulos. Athos: Efficient Authentication of Outsourced File Systems. In Proc. Int. Information Security Conference (ISC), Taipei, Taiwan, 2008. Charalampos Papamanthou, Franco P. Preparata, and Roberto Tamassia. Algorithms for Location Estimation Based on RSSI Sampling. In Proc. Int. ICALP Workshop on Algorithms for Sensor Networks (ALGOSENSORS), Reykjavik, Iceland, 2008. Roberto Tamassia, Bernardo Palazzi, and Charalampos Papamanthou. Graph Drawing for Security Visualization. In Proc. Int. Conference on Graph Drawing (GD), Heraklion, Greece, 2008. Charalampos Papamanthou and Roberto Tamassia. Time and Space Efficient Algorithms for Two-Party Authenticated Data Structures. In Proc. Int. Conference on Information and Communications Security (ICICS) Zhengzhou, China, 2007. Michael T. Goodrich, Charalampos Papamanthou, and Roberto Tamassia. On The Cost of Persistence and Authentication in Skip Lists. In Proc. Int. Workshop on Experimental Algorithms (WEA), Rome, Italy, 2007. Charalampos Papamanthou and Ioannis G. Tollis. Parameterized st-Orientations of Graphs: Algorithms and Experiments. In Proc. Int. Conference on Graph Drawing (GD), Karlsrühe, Germany, 2006. Charalampos Papamanthou and Ioannis G. Tollis. Applications of Parameterized st-Orientations in Graph Drawing Algorithms. In Proc. Int. Conference on Graph Drawing (GD)Limerick, Ireland, 2005. Charalampos Papamanthou, Ioannis G. Tollis, and Martin Doerr. 3D Visualization of Semantic Metadata Models and Ontologies. In Proc. Int. Conference on Graph Drawing (GD), New York City NY, USA, 2004. Charalampos Papamanthou and Konstantinos Paparrizos. A Visualization of the Primal Simplex Algorithm for the Assignment Problem. In Proc. Int. ACM Conference on Innovation and Technology in Computer Science Education (ITICSE), Thessaloniki, Greece, 2003.
	journals
	Dana Dachman-Soled, Chang Liu, Charalampos Papamanthou, Elaine Shi, and Uzi Vishkin. Oblivious Network RAM. Journal of Cryptology, 32:941–972, 2019. Yupeng Zhang, Charalampos Papamanthou, and Jonathan Katz. Verifiable Graph Processing. ACM Transactions on Privacy and Security, 21(4): 20:1-20:23, 2018. Daniel Genkin, Dimitrios Papadopoulos, and Charalampos Papamanthou. Privacy in Decentralized Cryptocurrencies. Communications of the ACM, 61(6):78–88, 2018. Ioannis Demertzis, Stavros Papadopoulos, Odysseas Papapetrou, Antonis Deligiannakis, Minos Garofalakis, and Charalampos Papamanthou. Practical Private Range Search In Depth. ACM Transactions on Database Systems, 43(1):2–52, 2018. Charalampos Papamanthou, Roberto Tamassia, and Nikos Triandopoulos. Authenticated Hash Tables Based on Cryptographic Accumulators. Algorithmica, 74(2):664-712, 2016. Chris C. Erway, Alptekin Küpçü, Charalampos Papamanthou, and Roberto Tamassia. Dynamic Provable Data Possession. ACM Transactions on Information and System Security, 17(4):15:1-15:29, 2015. Charalampos Papamanthou, Konstantinos Paparrizos, Nikolaos Samaras, and Angelo Sifaleras. On the Initialization Methods of an Exterior Point Algorithm for the Assignment Problem. International Journal of Computer Mathematics, 87(8):1831-1846, 2010. Charalampos Papamanthou and Ioannis G. Tollis. Applications of Parameterized st-Orientations. Journal of Graph Algorithms and Applications, 14(2):337-365, 2010. Claire Mathieu and Charalampos Papamanthou. Distortion Lower Bounds for Line Embeddings. Information Processing Letters, 108(4):175-178, 2008. Charalampos Papamanthou and Ioannis G. Tollis. Algorithms for Computing a Parameterized st-Orientation. Theoretical Computer Science, 408:224-240, 2008. Charalampos Papamanthou, Konstantinos Paparrizos, Nikolaos Samaras, and Konstantinos Stergiou. Worst Case Examples of an Exterior Point Algorithm for the Assignment Problem. Discrete Optimization, 5(3):605-614, 2008. Charalampos Papamanthou, Konstantinos Paparrizos, and Nikolaos Samaras. A Parametric Visualization Software for the Assignment Problem. Yugoslav Journal of Operations Research, 15(1):147-158, 2005. Charalampos Papamanthou, Konstantinos Paparrizos, and Nikolaos Samaras. Computational Experience with Exterior Point Algorithms for the Transportation Problem. Journal of Applied Mathematics and Computation, 158:459-475, 2004.
	chapters in books
	Olga Ohrimenko, Charalampos Papamanthou, and Bernaro Palazzi. Computer Security. Handbook of Graph Drawing and Visualization (Roberto Tamassia, editor), CRC press, 2013.
	other
	Charalampos Papamanthou. Cryptography for Efficiency: New Directions in Authenticated Data Structures. PhD thesis, Brown University, Providence RI, USA, May 2011.
	Charalampos Papamanthou. Computing Longest Path Parameterized st-Orientations of Graphs: Algorithms and Applications. Master's thesis, University of Crete, Heraklion, Greece, July 2005.
	Charalampos Papamanthou. Effective Programming, Computational Study and Internet Visualization of Network Programming Problems Algorithms. Bachelor's thesis, University of Macedonia, Thessaloniki, Greece, September 2003.