A concept named induced trapdoor one-way quantum transformation (OWQT) has been introduced, and a theoretical framework of public-key encryption (PKE) of quantum message is presented based on it. Then several kinds of quantum public-key encryption (QPKE) protocols, such as quantum version PKE of RSA, ElGamal, Goldwasser-Micali, elliptic curve, McEliece, Niederreiter and Okamoto-Tanaka-Uchiyama, are given within this framework. Though all of these protocols are only computationally secure, the last three are probably secure in post-quantum era. Besides, theoretical frameworks for public-key authentication and signature of quantum message are also given based on the induced trapdoor OWQT. As examples, a public-key authentication protocol of quantum message based on SN-S authentication scheme and two quantum digital signature protocols based on RSA and McEliece algorithms respectively are presented.
Trapdoor Functions with Secure Key Leasing and Copy Protection
NTT Social Informatics Laboratories（NTT社会信息学实验室）；NTT Research Center for Theoretical Quantum Information（NTT理论量子信息中心）；Yukawa Institute for Theoretical Physics, Kyoto University（京都大学汤川理论物理研究所）
Decision of whether a Boolean equation system has a solution is an NPC problem and finding a solution is NP hard. In this paper, we present a quantum algorithm to decide whether a Boolean equation system FS has a solution and compute one if FS does have solutions with any given success probability. The runtime complexity of the algorithm is polynomial in the size of FS and the condition number of FS. As a consequence, we give a polynomial-time quantum algorithm for solving Boolean equation systems if their condition numbers are small, say polynomial in the size of FS. We apply our quantum algo…
Due to Shor's algorithm, quantum computers are a severe threat for public key cryptography. This motivated the cryptographic community to search for quantum-safe solutions. On the other hand, the impact of quantum computing on secret key cryptography is much less understood. In this paper, we consider attacks where an adversary can query an oracle implementing a cryptographic primitive in a quantum superposition of different states. This model gives a lot of power to the adversary, but recent results show that it is nonetheless possible to build secure cryptosystems in it. We study application…
Given two elliptic curves over a finite field having the same cardinality and endomorphism ring, it is known that the curves admit an isogeny between them, but finding such an isogeny is believed to be computationally difficult. The fastest known classical algorithm takes exponential time, and prior to our work no faster quantum algorithm was known. Recently, public-key cryptosystems based on the presumed hardness of this problem have been proposed as candidates for post-quantum cryptography. In this paper, we give a subexponential-time quantum algorithm for constructing isogenies, assuming th…
