Publications
Journal Papers
Degree-Preserving Randomized Response for Graph Neural Networks under Local Differential Privacy
Seira Hidano*, Takao Murakami* (*: equal contribution)
Transactions on Data Privacy, Vol.17, Issue 2, pp.89-121, 2024.
[Published Version (Open Access)] [Code]Synthesizing Differentially Private Location Traces Including Co-Locations
Jun Narita, Takao Murakami, Hideitsu Hino, Masakatsu Nishigaki, Tetsushi Ohki
International Journal of Information Security, Vol. 23, pp.389-410, 2024.
[Published Version (Open Access)]Automatic Tuning of Privacy Budgets in Input-Discriminative Local Differential Privacy
Takao Murakami*, Yuichi Sei* (*: equal contribution)
IEEE Internet of Things Journal, Vol.10, No.18, pp.15990-16005, 2023.
[Published Version (Open Access)]Designing a Location Trace Anonymization Contest
Takao Murakami, Hiromi Arai, Koki Hamada, Takuma Hatano, Makoto Iguchi, Hiroaki Kikuchi, Atsushi Kuromasa, Hiroshi Nakagawa, Yuichi Nakamura, Kenshiro Nishiyama, Ryo Nojima, Hidenobu Oguri, Chiemi Watanabe, Akira Yamada, Takayasu Yamaguchi, Yuji Yamaoka
Proceedings on Privacy Enhancing Technologies (PoPETs), Issue 1, pp.225-243, 2023. [acceptance rate: 123/563 = 21.8%]
[Published Version (Open Access)] [Code]Toward Evaluating Re-identification Risks in the Local Privacy Model
Takao Murakami, Kenta Takahashi
Transactions on Data Privacy, Vol.14, Issue 3, pp.79-116, 2021.
[Published Version (Open Access)] [Code]Privacy-Preserving Multiple Tensor Factorization for Synthesizing Large-Scale Location Traces with Cluster-Specific Features
Takao Murakami, Koki Hamada, Yusuke Kawamoto, Takuma Hatano
Proceedings on Privacy Enhancing Technologies (PoPETs), Issue 2, pp.5-26, 2021. [acceptance rate: 82/436 = 18.8%]
[Published Version (Open Access)] [Code]Exposing Private User Behaviors of Collaborative Filtering via Model Inversion Techniques
Seira Hidano, Takao Murakami, Shuichi Katsumata, Shinsaku Kiyomoto, Goichiro Hanaoka
Proceedings on Privacy Enhancing Technologies (PoPETs), Issue 3, pp.264-283, 2020. [acceptance rate: 78/339 = 23.0%]
[Published Version (Open Access)]Cancelable Permutation-based Indexing for Secure and Efficient Biometric Identification
Takao Murakami, Ryo Fujita, Tetsushi Ohki, Yosuke Kaga, Masakazu Fujio, Kenta Takahashi
IEEE Access, Vol.7, pp.45563-45582, 2019.
[Published Version (Open Access)]Cancelable Indexing Based on Low-rank Approximation of Correlation-invariant Random Filtering for Fast and Secure Biometric Identification
Takao Murakami, Tetsushi Ohki, Yosuke Kaga, Masakazu Fujio, Kenta Takahashi
Elsevier Pattern Recognition Letters (Special Issue on Robustness, Security and Regulation Aspects in Current Biometric Systems), Vol.126, pp.11-20, 2019.
[Published Version (Open Access)]Signature Schemes with a Fuzzy Private Key
Kenta Takahashi, Takahiro Matsuda, Takao Murakami, Goichiro Hanaoka, Masakatsu Nishigaki
International Journal of Information Security, Vol.18, No.5, pp.581-617, 2019.
[Published Version (Open Access)]Model Inversion Attacks for Online Prediction Systems: Without Knowledge of Non-Sensitive Attributes
Seira Hidano, Takao Murakami, Shuichi Katsumata, Shinsaku Kiyomoto, Goichiro Hanaoka
IEICE Transactions on Information and Systems, Vol.101-D, No.11, pp.2665-2676, 2018.
[Published Version (Open Access)]How to Handle Excessively Anonymized Datasets
Ryo Nojima, Hidenobu Oguri, Hiroaki Kikuchi, Hiroshi Nakagawa, Koki Hamada, Takao Murakami, Yuji Yamaoka, Chiemi Watanabe
Journal of Information Processing, Vol.26, pp.477-485, 2018.
[Published Version (Open Access)]Toward Distribution Estimation under Local Differential Privacy with Small Samples
Takao Murakami, Hideitsu Hino, Jun Sakuma
Proceedings on Privacy Enhancing Technologies (PoPETs), Issue 3, pp.84-104, 2018. [acceptance rate: 36/218 = 16.5%]
[Published Version (Open Access)]Modality Selection Attacks and Modality Restriction in Likelihood-ratio Based Biometric Score Fusion
Takao Murakami, Yosuke Kaga, Kenta Takahashi
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, Vol.E100-A, No.12, pp.3023-3037, 2017.
[Published Version]Expectation-Maximization Tensor Factorization for Practical Location Privacy Attacks
Takao Murakami
Proceedings on Privacy Enhancing Technologies (PoPETs), Issue 4, pp.138-155, 2017. [acceptance rate: 52/231 = 22.5%]
[Published Version (Open Access)]Group Sparsity Tensor Factorization for Re-identification of Open Mobility Traces
Takao Murakami, Atsunori Kanemura, Hideitsu Hino
IEEE Transactions on Information Forensics and Security, Vol.12, No.3, pp.689-704, 2017.
[Published Version (Open Access)]Optimal Sequential Fusion for Multibiometric Cryptosystems
Takao Murakami, Tetsushi Ohki, Kenta Takahashi
Elsevier Information Fusion (Special Issue on Information Fusion in Biometrics), Vol.32, pp.93-108, 2016.
[Published Version]Localization Attacks Using Matrix and Tensor Factorization
Takao Murakami, Hajime Watanabe
IEEE Transactions on Information Forensics and Security, Vol.11, No.8, pp.1647-1660, 2016.
[Published Version]Information-theoretic Performance Evaluation of Multibiometric Fusion under Modality Selection Attacks
Takao Murakami, Yosuke Kaga, Kenta Takahashi
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, Vol.E99-A, No.5, pp.929-942, 2016.
[Published Version]A Measure of Information Gained through Biometric Systems
Kenta Takahashi, Takao Murakami
Elsevier Image and Vision Computing, Vol.32, No.12, pp.1194-1203, 2014.
[Published Version]A General Framework and Algorithms for Score Level Indexing and Fusion in Biometric Identification
Takao Murakami, Kenta Takahashi, Kanta Matsuura
IEICE Transactions on Information and Systems, Vol.E97-D, No.3, pp.510-523, 2014.
[Published Version]Toward Optimal Fusion Algorithms with Security against Wolves and Lambs in Biometrics
Takao Murakami, Kenta Takahashi, Kanta Matsuura
IEEE Transactions on Information Forensics and Security, Vol.9, No.2, pp.259-271, 2014.
[Published Version]Probabilistic Enhancement of Approximate Indexing in Metric Spaces
Takao Murakami, Kenta Takahashi, Susumu Serita, Yasuhiro Fujii
Elsevier Information Systems, Vol.38, No.7, pp.1007-1018, 2013.
[Published Version]
Conference Papers
CARGO: Crypto-Assisted Differentially Private Triangle Counting without Trusted Servers
Shang Liu, Yang Cao, Takao Murakami, Jinfei Liu, Masatoshi Yoshikawa
Proceedings of the 40th International Conference on Data Engineering (ICDE 2024), 2024 (to appear). [acceptance rate: 337/1481 = 22.8%]
[arXiv Version]Card-based Cryptography Meets Differential Privacy
Reo Eriguchi, Kazumasa Shinagawa, Takao Murakami
Proceedings of the 12th International Conference on Fun with Algorithms (FUN 2024), pp.12:1-12:20, 2024.
[Published Version (Open Access)]Two-Dimensional Dynamic Fusion for Continuous Authentication
Nuttapong Attrapadung, Goichiro Hanaoka, Haochen Kotoi-Xie, Takahiro Matsuda, Takumi Moriyama, Takao Murakami, Hidenori Nakamura, Jacob Schuldt, Masaaki Tokuyama, Jing Zhang
Proceedings of the 2023 IEEE International Joint Conference on Biometrics (IJCB 2023), pp.1-9, 2023. [acceptance rate: 72/199 = 36.2%]
[Published Version]A Crypto-Assisted Approach for Publishing Graph Statistics with Node Local Differential Privacy
Shang Liu, Yang Cao, Takao Murakami, Masatoshi Yoshikawa
Proceedings of the 2022 IEEE International Conference on Big Data (IEEE BigData 2022) (Special Session "Privacy and Security of Big Data"), pp.5765-5774, 2022.
[Published Version]Differentially Private Triangle and 4-Cycle Counting in the Shuffle Model
Jacob Imola*, Takao Murakami*, Kamalika Chaudhuri (*: equal contribution)
Proceedings of the 29th ACM Conference on Computer and Communications Security (CCS 2022), pp.1505-1519, 2022. [acceptance rate: 218/972 = 22.4%]
[Published Version (Open Access)] [Full Paper] [Code]Communication-Efficient Triangle Counting under Local Differential Privacy
Jacob Imola*, Takao Murakami*, Kamalika Chaudhuri (*: equal contribution)
Proceedings of the 31st USENIX Security Symposium (USENIX Security 2022), pp.537-554, 2022. [acceptance rate: 256/1414 = 18.1%]
[Published Version (Open Access)] [Full Paper] [Code]Synthesizing Privacy-Preserving Location Traces Including Co-locations
Jun Narita, Yayoi Suganuma, Masakatsu Nishigaki, Takao Murakami, Tetsushi Ohki
Proceedings of the 16th DPM International Workshop on Data Privacy Management (DPM 2021), pp.20-36, 2021.
[Published Version]Locality Sensitive Hashing with Extended Differential Privacy
Natasha Fernandes*, Yusuke Kawamoto*, Takao Murakami* (*: equal contribution)
Proceedings of the 26th European Symposium on Research in Computer Security (ESORICS 2021), pp.563-583, 2021. [acceptance rate: 71/351 = 20.2%]
[Published Version] [Full Paper]TransMIA: Membership Inference Attacks Using Transfer Shadow Training
Seira Hidano, Takao Murakami, Yusuke Kawamoto
Proceedings of the 2021 International Joint Conference on Neural Networks (IJCNN 2021), pp.1-10, 2021.
[Published Version] [Full Paper]Locally Differentially Private Analysis of Graph Statistics
Jacob Imola*, Takao Murakami*, Kamalika Chaudhuri (*: equal contribution)
Proceedings of the 30th USENIX Security Symposium (USENIX Security 2021), pp.983-1000, 2021. [acceptance rate: 246/1316 = 18.7%]
[Published Version (Open Access)] [Full Paper] [Code]Local Distribution Obfuscation via Probability Coupling
Yusuke Kawamoto, Takao Murakami
Proceedings of the 57th Annual Allerton Conference on Communication, Control, and Computing (Allerton 2019), pp.718-725, 2019.
[Published Version (Open Access)] [Full Paper]Local Obfuscation Mechanisms for Hiding Probability Distributions
Yusuke Kawamoto, Takao Murakami
Proceedings of the 24th European Symposium on Research in Computer Security (ESORICS 2019), pp.128-148, 2019. [acceptance rate: 67/344 = 19.5%]
[Published Version] [Full Paper]Utility-Optimized Local Differential Privacy Mechanisms for Distribution Estimation
Takao Murakami, Yusuke Kawamoto
Proceedings of the 28th USENIX Security Symposium (USENIX Security 2019), pp.1877-1894, 2019. [acceptance rate: 113/719 = 15.7%]
[Published Version (Open Access)] [Full Paper]Improved Security Evaluation Techniques for Imperfect Randomness from Arbitrary Distributions
Takahiro Matsuda, Kenta Takahashi, Takao Murakami, Goichiro Hanaoka
Proceedings of the 22nd International Conference on Practice and Theory of Public Key Cryptography (PKC 2019), pp.549-580, 2019. [acceptance rate: 42/172 = 24.4%]
[Published Version]A Generalization of the Theory of Biometric System Entropy
Kenta Takahashi, Takao Murakami
Proceedings of the 2018 Asia-Pacific Signal and Information Processing Association Annual Summit and Conference (APSIPA ASC 2018), pp.1-6, 2018.
[Published Version (Open Access)]On the Anonymization of Differentially Private Location Obfuscation
Yusuke Kawamoto, Takao Murakami
Proceedings of the 2018 International Symposium on Information Theory and Its Applications (ISITA 2018), pp.159-163, 2018.
[Published Version]A Succinct Model for Re-identification of Mobility Traces Based on Small Training Data
Takao Murakami
Proceedings of the 2018 International Symposium on Information Theory and Its Applications (ISITA 2018), pp.164-168, 2018.
[Published Version]Face/Fingerphoto Spoof Detection under Noisy Conditions by Using Deep Convolutional Neural Network
Masakazu Fujio, Yosuke Kaga, Takao Murakami, Tetsushi Ohki, Kenta Takahashi
Proceedings of the 11th International Conference on Bio-inspired Systems and Signal Processing (BIOSIGNALS 2018), pp.54-62, 2018.A Secure and Practical Signature Scheme for Blockchain Based on Biometrics
Yosuke Kaga, Masakazu Fujio, Ken Naganuma, Kenta Takahashi, Takao Murakami, Tetsushi Ohki, Masakatsu Nishigaki
Proceedings of the 3rd International Symposium on Security and Privacy in Social Networks and Big Data (SocialSec 2017), pp.877-891, 2017.
[Published Version]Model Inversion Attacks for Prediction Systems: Without Knowledge of Non-Sensitive Attributes
Seira Hidano, Takao Murakami, Shuichi Katsumata, Shinsaku Kiyomoto, Goichiro Hanaoka
Proceedings of the 15th International Conference on Privacy, Security, and Trust (PST 2017), pp.115-126, 2017.
[Published Version]On Restricting Modalities in Likelihood-ratio Based Biometric Score Fusion
Takao Murakami, Yosuke Kaga, Kenta Takahashi
Proceedings of the 23rd International Conference on Pattern Recognition (ICPR 2016), pp.3031-3037, 2016.
[Published Version]Fuzzy Signatures: Relaxing Requirements and a New Construction
Takahiro Matsuda, Kenta Takahashi, Takao Murakami, Goichiro Hanaoka
Proceedings of the 14th International Conference on Applied Cryptography and Network Security (ACNS 2016), LNCS 9696, pp.97-116, 2016. [acceptance rate: 35/183 = 19.1%]
[Published Version]Information-theoretic Performance Evaluation of Likelihood-ratio Based Biometric Score Fusion under Modality Selection Attacks
Takao Murakami, Kenta Takahashi
Proceedings of the 7th IEEE International Conference on Biometrics: Theory, Applications and Systems (BTAS 2015), pp.1-8, 2015. [acceptance rate (oral): 29/130 = 22.3%]
[Published Version]Group Sparsity Tensor Factorization for De-anonymization of Mobility Traces
Takao Murakami, Atsunori Kanemura, Hideitsu Hino
Proceedings of the 14th IEEE International Conference on Trust, Security and Privacy in Computing and Communications (TrustCom 2015), pp.621-629, 2015. [acceptance rate: 79/278 = 28.4%]
[Best Paper Award (one of top 2 papers)]
[Published Version]A Signature Scheme with a Fuzzy Private Key
Kenta Takahashi, Takahiro Matsuda, Takao Murakami, Goichiro Hanaoka, Masakatsu Nishigaki
Proceedings of the 13th International Conference on Applied Cryptography and Network Security (ACNS 2015), LNCS 9092, pp.105-126, 2015. [acceptance rate: 33/157 = 21.0%]
[Published Version]Location Prediction Attacks Using Tensor Factorization and Optimal Defenses
Takao Murakami, Hajime Watanabe
Proceedings of the 1st IEEE International Workshop on Big Data Security and Privacy (BDSP 2014), workshop at IEEE BigData2014, pp.13-21, 2014.
[Published Version]Towards Optimal Countermeasures against Wolves and Lambs in Biometrics
Takao Murakami, Kenta Takahashi, Kanta Matsuura
Proceedings of the 5th IEEE International Conference on Biometrics: Theory, Applications and Systems (BTAS 2012), pp.69-76, 2012. [acceptance rate (oral): 32/144 = 22.2%]
[Best Reviewed Paper (one of top 4 papers)]
[Published Version]Fast and Accurate Biometric Identification Using Score Level Indexing and Fusion
Takao Murakami, Kenta Takahashi
Proceedings of the IEEE/IAPR International Joint Conference on Biometrics (IJCB 2011), pp.1-8, 2011. [acceptance rate: 107/324 = 33.0%]
[Published Version]Versatile Probability-based Indexing for Approximate Similarity Search
Takao Murakami, Kenta Takahashi, Susumu Serita, Yasuhiro Fujii
Proceedings of the 4th ACM International Conference on Similarity Search and Applications (SISAP 2011), pp.51-58, 2011.
[Best Paper (one of top 3 papers)]
[Published Version]A Metric of Information Gained through Biometric Systems
Kenta Takahashi, Takao Murakami
Proceedings of the 20th International Conference on Pattern Recognition (ICPR 2010), pp.1184-1187, 2010.
[Published Version]Accuracy Improvement with High Convenience in Biometric Identification Using Multihypothesis Sequential Probability Ratio Test
Takao Murakami, Kenta Takahashi
Proceedings of the 1st IEEE International Workshop on Information Forensics and Security (WIFS 2009), pp.66-70, 2009. [acceptance rate: 39/124 = 31.5%]
[Published Version]Speech Recognition Only with Supra-segmental Features --- Hearing Speech as music ---
Nobuaki Minematsu, Tazuko Nishimura, Takao Murakami, Keikichi Hirose
Proceedings of the International Conference on Speech Prosody, pp.589-594, 2006.Japanese Vowel Recognition Using External Structure of Speech
Takao Murakami, Kazutaka Maruyama, Nobuaki Minematsu Keikichi Hirose
Proceedings of the IEEE Automatic Speech Recognition and Understanding Workshop (ASRU 2005), pp.203-208, 2005. [acceptance rate: 73/(approximately)180 = 40%]Japanese Vowel Recognition Based on Structural Representation of Speech
Takao Murakami, Kazutaka Maruyama, Nobuaki Minematsu, Keikichi Hirose
Proceedings of the 9th European Conference on Speech Communication and Technology (Interspeech 2005), pp.1261-1264, 2005.
Talks
Overview of Privacy-Preserving Technologies
Takao Murakami
From 304dB to Geoworld-dB (Pre-Workshop of FOMLIG & UUGGP 2023), 2023.Toward Accurate Data Analysis under Local Privacy
Takao Murakami
The 16th International Workshop on Security (IWSEC 2021), Keynote Talk, 2021. [Slide]Locally Differentially Private Analysis of Graph Statistics (from Usenix Security 2021)
Takao Murakami
IT-Security & Privacy Colloquium, the University of Luebeck, 2021.Toward Distribution Estimation under Local Differential Privacy with Small Samples
Takao Murakami
CSE 259 (Seminar in Artificial Intelligence), Fall 2018 AI Seminar, UC San Diego, 2018.Quantifying the Risk of Re-identification in Data Anonymization Competition
Takao Murakami
Workshop on Design Issues for a data Anonymization Competition (WODIAC), workshop at PETS 2017, 2017.