NTT Research Presents 23 Papers at Crypto 2025 Conference

NTT Research and NTT R&D scientists will present 23 papers – approximately 15% of the total accepted – at the Crypto 2025 conference, held virtually and in Santa Barbara, California, from August 17-21. Senior Scientist Mark Zhandry and Postdoctoral Fellow Omri Shmueli received the conference’s Best Paper Award for their work on one-shot signatures (OSS), a quantum-based digital signature method designed to limit signing to a single contract. This research builds upon prior work from 2020, achieving the first standard-model OSS with provable security based on indistinguishability obfuscation and Learning With Errors, alongside a resolution of a decade-old open problem concerning classical and quantum commitments. In addition to these contributions, NTT scientists are presenting research on topics including post-quantum secure computation and secure key leasing.

Overview

NTT Research and NTT R&D scientists are presenting 23 papers at Crypto 2025, constituting approximately 15 per cent of the total accepted papers at the conference. The International Association for Cryptologic Research (IACR) organizes Crypto 2025, which will take place virtually and in Santa Barbara, California, from August 17-21, 2025. This substantial contribution underscores the organizations’ dedication to advancing the foundations of digital security and privacy.

Research conducted by NTT Research Senior Scientist Mark Zhandry and Postdoctoral Fellow Omri Shmueli has been recognised with the conference’s Best Paper Award. Their work focuses on one-shot signatures (OSS), a solution designed to guarantee a signing party can only sign a single contract, thereby preventing subsequent agreements with competitors. Digital signatures authenticate digital messages, but OSS offers a stronger security level beyond simple source verification.

Zhandry and Shmueli’s research builds upon earlier work defining OSS, initially presented by Amos et al. in 2020. However, their research addresses a flawed justification present in the prior work and achieves three key breakthroughs. These include the first standard-model OSS with provable security based on indistinguishability obfuscation and Learning With Errors, the first standard-model separation between classical and collapse-binding post-quantum commitments/hashing, and the first construction with unconditional security relative to a classical oracle.

In addition to the 17 papers authored or co-authored by NTT Research scientists, six papers from NTT R&D Social Informatics Laboratories (SIL) scientists and collaborators are also being presented. These papers cover a range of topics including cryptographic treatment of key control security, multi-user security of key-alternating Feistel ciphers, and attacks on Falcon. A complete list of accepted papers is available on the Crypto 2025 webpage.

NTT’s commitment extends to fundamental research and the development of technologies enhancing digital privacy and security, including work on attribute-based encryption (ABE). ABE, first proposed in 2004, enables fine-grained access control based on attributes and policies. NTT Research’s Brent Waters has received seven and eight Test-of-Time Awards, recognising research that has significantly contributed to long-term advancements in cryptography and information security.

Key Details

The research achieving these breakthroughs establishes the first standard-model separation between classical and collapse-binding post-quantum commitments/hashing, resolving an open problem that has remained unsolved for a decade. Additionally, the work presents the first construction with unconditional security relative to a classical oracle. Potential applications of one-shot signatures include one-time signature tokens, quantum money with classical communication, and decentralized cryptocurrencies.

The six papers presented by NTT R&D Social Informatics Laboratories (SIL) scientists and collaborators cover topics such as the multi-user security of key-alternating Feistel ciphers, the round complexity of post-quantum secure computation, and quantum lifting for invertible permutations. Further research detailed in these papers concerns attacks on Falcon and the cryptographic treatment of key control security. A complete listing of accepted papers for the conference can be found on the Crypto 2025 webpage.

NTT Research’s Brent Waters was recently awarded his seventh and eighth Test-of-Time Awards, recognising research that has made significant contributions to long-term advancements in cryptography and information security. This recognition follows Waters’ earlier work on attribute-based encryption (ABE), initially proposed in 2004, which allows for fine-grained access control based on attributes and policies.

Conclusion

The conference’s Best Paper Award was presented to NTT Research Senior Scientist Mark Zhandry and Postdoctoral Fellow Omri Shmueli for their work on “On One-Shot Signatures, Quantum vs Classical Binding, and Obfuscating Permutations.” Digital signatures authenticate digital messages, but stronger security is often required beyond simply verifying the source, a need addressed by their research. One-shot signatures (OSS) offer a solution by leveraging quantum information to guarantee a signing party can only sign a single contract, preventing subsequent agreements with competitors.

Zhandry and Shmueli’s research builds upon prior work from 2020, which initially defined OSS; however, the earlier research relied on an artificial oracle model and contained a flawed justification. The new research achieves three key breakthroughs: the first standard-model OSS with provable security based on established cryptographic assumptions (indistinguishability obfuscation and Learning With Errors); the first standard-model separation between classical and collapse-binding post-quantum commitments/hashing, resolving a decade-old open problem; and the first construction with unconditional security relative to a classical oracle. Potential applications of OSS include one-time signature tokens, quantum money with classical communication, and decentralized cryptocurrencies.

In total, NTT Research and NTT R&D scientists are presenting 23 papers at Crypto 2025, representing approximately 15% of the total accepted papers at the conference. This includes 17 papers authored or co-authored by NTT Research scientists, alongside six papers from NTT R&D Social Informatics Laboratories (SIL) scientists and collaborators. These additional papers cover topics such as cryptographic treatment of key control security, multi-user security of key-alternating Feistel ciphers, round complexity of post-quantum secure computation, attacks on Falcon, quantum lifting for invertible permutations, and secure key leasing.