36 citations · 73 across the 18 of their papers we have counts for
22 papers
Quantum Leakage Resilience of Shamir Secret Sharing
Rishabh Batra, Fuyuki Kitagawa, Ryo Nishimaki +1
We initiate the study of quantum leakage resilience of unmodified Shamir secret sharing over prime fields. A well-studied leakage model for Shamir's secret sharing classically is s…
Trapdoor Functions with Secure Key Leasing and Copy Protection
Fuyuki Kitagawa, Ryo Nishimaki, Yuki Shirakawa +1
Inspired by the no-cloning theorem in quantum theory, a variety of quantum cryptographic primitives with unclonable functionalities, such as secure key leasing and copy protection,…
Towards the Impossibility of Imperfectly Complete Key Agreement in the QROM
Fuyuki Kitagawa, Ryo Nishimaki, Agi Villanyi +1
We make progress towards the impossibility of quantum-computation, classical-communication (QCCC) key agreement by giving the first unconditional polynomial-query attacks that tole…
Separating Non-Interactive Classical Verification of Quantum Computation from Falsifiable Assumptions
Mohammed Barhoush, Tomoyuki Morimae, Ryo Nishimaki +1
Mahadev [SIAM J. Comput. 2022] introduced the first protocol for classical verification of quantum computation based on the Learning-with-Errors (LWE) assumption, achieving a 4-mes…
Multi-Copy Security in Quantum Cryptography and More
Alper Çakan, Vipul Goyal, Fuyuki Kitagawa +2
Unclonable cryptography uses the quantum no-cloning principle to achieve security guarantees that are impossible in a classical world. Most existing works, however, consider only s…
Collusion-Resistant Quantum Secure Key Leasing Beyond Decryption
Fuyuki Kitagawa, Ryo Nishimaki, Nikhil Pappu
Secure key leasing (SKL) enables the holder of a secret key for a cryptographic function to temporarily lease the key using quantum information. Later, the recipient can produce a…
MicroCrypt Assumptions with Quantum Input Sampling and Pseudodeterminism: Constructions and Separations
Mohammed Barhoush, Ryo Nishimaki, Takashi Yamakawa
We investigate two natural relaxations of quantum cryptographic primitives. The first involves quantum input sampling, where inputs are generated by a quantum algorithm rather than…
PKE and ABE with Collusion-Resistant Secure Key Leasing
Fuyuki Kitagawa, Ryo Nishimaki, Nikhil Pappu
Secure key leasing (SKL) is an advanced encryption functionality that allows a secret key holder to generate a quantum decryption key and securely lease it to a user. Once the user…
Untelegraphable Encryption and its Applications
Jeffrey Champion, Fuyuki Kitagawa, Ryo Nishimaki +1
We initiate the study of untelegraphable encryption (UTE), founded on the no-telegraphing principle, which allows an encryptor to encrypt a message such that a binary string repres…
Robust Combiners and Universal Constructions for Quantum Cryptography
Taiga Hiroka, Fuyuki Kitagawa, Ryo Nishimaki +1
A robust combiner combines many candidates for a cryptographic primitive and generates a new candidate for the same primitive. Its correctness and security hold as long as one of t…
Publicly Verifiable Deletion from Minimal Assumptions
Fuyuki Kitagawa, Ryo Nishimaki, Takashi Yamakawa
We present a general compiler to add the publicly verifiable deletion property for various cryptographic primitives including public key encryption, attribute-based encryption, and…
Quantum Public-Key Encryption with Tamper-Resilient Public Keys from One-Way Functions
Fuyuki Kitagawa, Tomoyuki Morimae, Ryo Nishimaki +1
We construct quantum public-key encryption from one-way functions. In our construction, public keys are quantum, but ciphertexts are classical. Quantum public-key encryption from o…
One-out-of-Many Unclonable Cryptography: Definitions, Constructions, and More
Fuyuki Kitagawa, Ryo Nishimaki
The no-cloning principle of quantum mechanics enables us to achieve amazing unclonable cryptographic primitives, which is impossible in classical cryptography. However, the securit…
Public Key Encryption with Secure Key Leasing
Shweta Agrawal, Fuyuki Kitagawa, Ryo Nishimaki +2
We introduce the notion of public key encryption with secure key leasing (PKE-SKL). Our notion supports the leasing of decryption keys so that a leased key achieves the decryption…
Obfuscation of Pseudo-Deterministic Quantum Circuits
James Bartusek, Fuyuki Kitagawa, Ryo Nishimaki +1
We show how to obfuscate pseudo-deterministic quantum circuits in the classical oracle model, assuming the quantum hardness of learning with errors. Given the classical description…
Certified Everlasting Secure Collusion-Resistant Functional Encryption, and More
Taiga Hiroka, Fuyuki Kitagawa, Tomoyuki Morimae +3
We study certified everlasting secure functional encryption (FE) and many other cryptographic primitives in this work. Certified everlasting security roughly means the following. A…
Functional Encryption with Secure Key Leasing
Fuyuki Kitagawa, Ryo Nishimaki
Secure software leasing is a quantum cryptographic primitive that enables us to lease software to a user by encoding it into a quantum state. Secure software leasing has a mechanis…
Certified Everlasting Functional Encryption
Taiga Hiroka, Tomoyuki Morimae, Ryo Nishimaki +1
Computational security in cryptography has a risk that computational assumptions underlying the security are broken in the future. One solution is to construct information-theoreti…
Watermarking PRFs against Quantum Adversaries
Fuyuki Kitagawa, Ryo Nishimaki
We initiate the study of software watermarking against quantum adversaries. A quantum adversary generates a quantum state as a pirate software that potentially removes an embedded…
Certified Everlasting Zero-Knowledge Proof for QMA
Taiga Hiroka, Tomoyuki Morimae, Ryo Nishimaki +1
In known constructions of classical zero-knowledge protocols for NP, either of zero-knowledge or soundness holds only against computationally bounded adversaries. Indeed, achieving…
Quantum Encryption with Certified Deletion, Revisited: Public Key, Attribute-Based, and Classical Communication
Taiga Hiroka, Tomoyuki Morimae, Ryo Nishimaki +1
Broadbent and Islam (TCC '20) proposed a quantum cryptographic primitive called quantum encryption with certified deletion. In this primitive, a receiver in possession of a quantum…
Secure Software Leasing from Standard Assumptions
Fuyuki Kitagawa, Ryo Nishimaki, Takashi Yamakawa
Secure software leasing (SSL) is a quantum cryptographic primitive that enables users to execute software only during the software is leased. It prevents users from executing lease…