NTT Scientists advance knowledge of attribute-based encryption (ABE), quantum cryptography, secure Multi-Party Computation (MPC), and more at prestigious conference
News Highlights:
- Scientists at the NTT Cryptography & Information Security (CIS) Lab and NTT Social Informatics Laboratories (SIL) authored or co-authored 20 papers delivered at this top-tier conference.
- Four of the twenty focus on ABE, a field pioneered by NTT Research CIS Lab Director Brent Waters.
- The SIL and CIS Lab scientists presented multiple papers in six categories, including Quantum, MPC, ABE, and Non-Interactive Zero-Knowledge Proofs (NIZKs).
- The CIS Lab continues to evince a uniquely collaborative environment, adept at recognizing new talent, as seen in a paper on secure Multi-Party Computation (MPC).
SUNNYVALE, Calif. and TOKYO – May 19, 2025 – NTT Research, Inc. and NTT R&D, divisions of NTT (TYO:9432), announced that their cryptographic teams delivered twenty papers at Eurocrypt 2025 in Madrid, May 4-8. Five of the papers were co-authored by scientists from NTT Social Informatics Laboratories (SIL); the other fifteen were authored or co-authored by scientists from the NTT Research Cryptography & Information Security (CIS) Lab. Four focused on Attribute-Based Encryption (ABE), an area of commercial interest for NTT and NTT DATA.
Eurocrypt is one of three flagship conferences organized by the International Association for Cryptologic Research (IACR). Eurocrypt 2025 is formally known as the 44th Annual International Conference on the Theory and Applications of Cryptographic Techniques. This year’s 130-member program committee accepted 123 papers, slotting them into 36 separate sessions. The CIS and SIL Labs presented multiple papers in six of those session categories: Anamorphic & Broadcast Encryption, Non-Interactive Zero-Knowledge Proofs (NIZKs), Obfuscation & ABE, Quantum, Succinct & Evasive Learning with Errors (LWE) and Verifiable Deletion.
“The CIS Lab is honored to be part of Eurocrypt 2025 and congratulates our NTT SIL colleagues for their contributions to this important conference,” CIS Lab Director Brent Waters said. “We are excited with our work, both in-house and with the co-authors represented in these papers, and value our ongoing engagement with other parts of NTT and colleagues in the cryptographic field at large.”
Four CIS Lab papers address ABE, a kind of encryption pioneered two decades ago by Waters that enables fine-grained access control of encrypted data. Two of these papers address ABE from lattice-based LWE hardness assumptions. Building ABE on that basis, according to CIS Lab Senior Scientist Hoeteck Wee, enables quantum resistance, support for more expressive policies, and much smaller parameters. In one of those two papers, “Almost Optimal KP and CP-ABE for Circuits from Succinct LWE,” Wee optimizes key-policy (KP) and cipher-text policy (CP) for ABE with respect to metrics such as circuit size and input length. The second paper, “Faster ABE for Turing Machines from Circular Evasive LWE,” which Wee co-authored with Valerio Cini from Bocconi University, improves ABE through faster encryption and smaller cipher-text and key sizes. Both papers lean on weaker LWE-type assumptions. In cryptography, the “weaker” the assumption, the stronger the construction is considered.
“Most existing ABE schemes only support access policies where the input size is fixed in advance,” Wee said. “Our current work continues a line of work on supporting policies over unbounded input size, which captures many real-world applications such as network monitoring and logging, pattern matching in gene sequences and processing tax returns.”
Another Eurocrypt 2025 paper, “Simultaneous-Message and Succinct Secure Computation,” which falls into the category of secure Multi-Party Computation (MPC), illustrates both the CIS Lab’s work in this area and its distinctive modus operandi. At the Upgrade 2024 event, CIS Lab Senior Scientist and paper author Elette Boyle admitted that when she first started working on MPC, which involves computation on data that remain private, it seemed “like magic.” But while possible, it required new foundations and different approaches to make it less expensive. In this paper, she and her three co-authors advance an approach that enables succinct and simultaneous MPC communications for general secure computations.
“A significant challenge is in obtaining low communication when one party has a long input and the other has a short input. This setting constitutes a gap, where without security you only need to communicate as much as the small input size; but in previous solutions with security, you still had to communicate as much as the large input,” Boyle said. “In our work this is no longer the case.”
Co-author and CIS Lab Senior Scientist Abhishek Jain added: “From an application perspective, this setting corresponds to a natural client-server model where the server has a large input and the client has a small input.”
This paper also highlights the CIS Lab’s unique culture. Boyle and CIS Lab Senior Scientist Abhishek Jain collaborated with MIT Ph.D. candidate Sacha Servan-Schreiber, as well as University of Toronto Assistant Professor Akshayaram Srinivasan. “Sacha came as an intern, and Abhishek and I worked together with him on this project, together with Akshay, who joined remotely,” Boyle said. “This is one of the special opportunities of working at NTT Research, having accessibility to other cryptographic experts, and as an effect, the ability to draw top young talent.”
Twelve other papers affiliated with members of the CIS Lab were presented at Eurocrypt 2025, including (with session categories) the following:
- “Optimal Traitor Tracing from Pairings” (Anamorphic & Broadcast Encryption), Mark Zhandry
- “On Quantum Money and Evasive Obfuscation” (Obfuscation & ABE), Mark Zhandry1
- “New Techniques for Preimage Sampling: Improved NIZKs and More from LWE” (NIZKs), Brent Waters1,2, Hoeteck Wee1, David J. Wu2
- “Quantum Key Leasing for PKE and FHE with a Classical Lessor” (Verifiable Deletion), Orestis Chardouvelis, Vipul Goyal3,1, Aayush Jain3, Jiahui Liu3
- “The Complexity of Memory Checking with Covert Security” (Foundations) Elette Boyle1,, Ilan Komargodski1,, Neekon Vafa
- “A Generic Approach to Adaptively-Secure Broadcast Encryption in the Plain Model” (Anamorphic & Broadcast Encryption) Yao-Ching Hsieh, Brent Waters1,2, David J. Wu2
- “Unique NIZKs and Steganography Detection” (NIZKs) Willy Quach, LaKyah Tyner, Daniel Wichs9,1
- “Multi-key Homomorphic Secret Sharing” (Secret Sharing), Geoffroy Couteau, Lalita Devadas6, Aditya Hegde, Abhishek Jain1,11, Sacha Servan-Schreiber6
- “Black-Box Non-Interactive Zero Knowledge from Vector Trapdoor Hash” (NIZKs), Pedro Branco, Arka Rai Choudhuri1, Nico Döttling, Abhishek Jain1, Giulio Malavolta12, Akshayaram Srinivasan
- “Hard Quantum Extrapolations in Quantum Cryptography” (Quantum), Luowen Qian1, Justin Raizes3, Mark Zhandry1
- “Multi-Authority Registered Attribute-Based Encryption” (Obfuscation & ABE), George Lu2,1, Brent Waters1,2, David J. Wu2
- “Black Box Crypto is Useless for Doubly Efficient PIR” (Private Information Retrieval), Wei-Kai Lin, Ethan Mook9, Daniel Wichs1,9
In addition, five papers co-authored by NTT SIL Labs scientists were presented at Eurocrypt 2025. They include (with session categories) the following:
- “Cryptanalysis of Full SCARF” (Advanced Block Ciphers), Antonio Flórez-Gutiérrez, Eran Lambooij, Gaëtan Leurent, Håvard Raddum, Tyge Tiessen, Michiel Verbauwhede
- “Improved Cryptanalysis of ChaCha: Beating PNBs with Bit Puncturing” (Symmetric Cryptanalysis) Antonio Flórez-Gutiérrez16, Yosuke Todo16
- “A New World in the Depths of Microcrypt: Separating OWSGs and Quantum Money from QEFID” (Quantum), Amit Behera, Giulio Malavolta12, Tomoyuki Morimae, Tamer Mour12, Takashi Yamakawa16
- “A Simple Framework for Secure Key Leasing” (Verifiable Deletion), Fuyuki Kitagawa16,24, Tomoyuki Morimae23, Takashi Yamakawa16,24,23
- “Do Not Disturb a Sleeping Falcon: Floating-Point Error Sensitivity of the Falcon Sampler and Its Consequences” (Hawk & Falcon), Xiuhan Lin, Mehdi Tibouchi16, Yang Yu, Shiduo Zhang25
The proceedings of Eurocrypt 2025 will be published in Springer’s Lecture Notes in Computer Science (LNCS) series. Sponsors of this year’s event were Zama and Midnight (Platinum); IMDEA Software Institute, Apple, Google, and Huawei (Gold); GMV, CMAD, AWS, and TII (Silver); and HEaaN CryptoLab, NEC, NTT Research, PQ Shield, IBM, Orange, and Ericsson (Bronze).
Part of NTT Research, the CIS Lab has assembled a team of world-class scientists whose work has made landmark contributions in the field of cryptography through their prominent participation in leading international conferences. NTT SIL is part of NTT R&D in Tokyo. The CIS Lab and NTT SIL collaborate across many areas of cryptography research to collectively advance future cybersecurity technologies.
About NTT Research
NTT Research opened its offices in July 2019 in Silicon Valley to conduct basic research and advance technologies as a foundational model for developing high-impact innovation across NTT Group’s global business. Currently, four groups are housed at NTT Research facilities in Sunnyvale: the Physics and Informatics (PHI) Lab, the Cryptography and Information Security (CIS) Lab, the Medical and Health Informatics (MEI) Lab, and the Physics of Artificial Intelligence (PAI) Group. The organization aims to advance science in four areas: 1) quantum information, neuroscience and photonics; 2) cryptographic and information security; 3) medical and health informatics; and 4) artificial intelligence. NTT Research is part of NTT, a global technology and business solutions provider with an annual R&D investment of thirty percent of its profits.
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Footnotes:
1 NTT Research
2 University of Texas, Austin
3 Carnegie Mellon University
4 Reichman University
5 The Hebrew University of Jerusalem
6 Massachusetts Institute of Technology
7 University of Washington
8 CISPA Helmholtz Center for Information Security
9 Northeastern University
10 CNRS, IRIF, Université Paris Cité
11 Johns Hopkins University
12 Bocconi University
13 Helmholtz Center for Information Security
14 University of Toronto
15 University of Virginia
16 NTT Social Informatics Laboratories
17 Bar-Ilan University
18 Inria, Paris
19 Simula UiB, Bergen
20 Technical University of Denmark
21 COSIC, KU Leuven
22 Ben-Gurion University of the Negev
23 Kyoto University
24 Shandong University
25 Tsinghua University