6 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…
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…
On the Cryptographic Futility of Non-Collapsing Measurements
Alper Cakan, Dakshita Khurana, Tomoyuki Morimae +3
We investigate quantum analogues of collision resistance and obtain separations between quantum ``one-way'' and ``collision-resistant'' primitives. 1. Our first result studies one-…
A Unified Approach to Quantum Key Leasing with a Classical Lessor
Fuyuki Kitagawa, Jiahui Liu, Shota Yamada +1
Secure key leasing allows a cryptographic key to be leased as a quantum state in such a way that the key can later be revoked in a verifiable manner. In this work, we propose a mod…