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Bit-string oblivious transfer based on quantum state computational distinguishability

Souto, A. ; Mateus, P. ; Adão, P. ; Paunkovic, N.

Physical Review A - Atomic, Molecular, and Optical Physics Vol. 91, Nº 1, pp. 042306 - 042306, April, 2015.

ISSN (print): 1050-2947
ISSN (online): 1094-1622

Scimago Journal Ranking: 1,75 (in 2015)

Digital Object Identifier: 10.1103/PhysRevA.91.042306

Oblivious transfer protocol is a basic building block in cryptography and is used to transfer information from a sender to a receiver in such a way that, at the end of the protocol, the sender does not know if the receiver got the message or not. Since Shor's quantum algorithm appeared, the security of most of the classical cryptographic schemes has been compromised, as they rely on the fact that factoring is infeasible. To overcome this, quantum mechanics has been used intensively in the past decades, and alternatives resistant to quantum attacks have been developed in order to fulfill the (potential) lack of security of a significant number of classical schemes. In this paper, we present a quantum computationally secure protocol for bit-string oblivious transfer between two parties, under the assumption of quantum hardness of state distinguishability and the constraint of performing at most few-qubit measurements (leaving open the question of general attacks performed on all qubits involved). The protocol is feasible, in the sense that it is implementable in polynomial time.