activity
20242026
collaborators

8 papers

quant-ph2026

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…

quant-ph2025

Multi-Copy Security in Unclonable Cryptography

Alper Çakan, Vipul Goyal, Fuyuki Kitagawa +2

Unclonable cryptography leverages the quantum no-cloning principle to copy-protect cryptographic functionalities. While most existing works address the basic single-copy security,…

quant-ph2025

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…

quant-ph2025

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…

cs.CR2025

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…

quant-ph2025

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…