International Association for Cryptologic Research

International Association
for Cryptologic Research


A New Framework for Quantum Oblivious Transfer

Amit Agarwal , University of Illinois Urbana-Champaign
James Bartusek , UC Berkeley
Dakshita Khurana , University of Illinois Urbana-Champaign
Nishant Kumar , University of Illinois Urbana-Champaign
DOI: 10.1007/978-3-031-30545-0_13 (login may be required)
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Presentation: Slides
Conference: EUROCRYPT 2023
Abstract: We present a new template for building oblivious transfer from quantum information that we call the "fixed basis'' framework. Our framework departs from prior work (eg., Crepeau and Kilian, FOCS '88) by fixing the *correct* choice of measurement basis used by each player, except for some hidden *trap* qubits that are intentionally measured in a conjugate basis. We instantiate this template in the quantum random oracle model (QROM) to obtain simple protocols that implement, with security against malicious adversaries: 1. *Non-interactive* random-input bit OT in a model where parties share EPR pairs a priori. 2. Two-round random-input bit OT without setup, obtained by showing that the protocol above remains secure even if the (potentially malicious) OT receiver sets up the EPR pairs. 3. Three-round chosen-input string OT from BB84 states without entanglement or setup. This improves upon natural variations of the CK88 template that require at least five rounds. Along the way, we develop technical tools that may be of independent interest. We prove that natural functions like XOR enable *seedless* randomness extraction from certain quantum sources of entropy. We also use idealized (i.e. extractable and equivocal) bit commitments, which we obtain by proving security of simple and efficient constructions in the QROM.
  title={A New Framework for Quantum Oblivious Transfer},
  author={Amit Agarwal and James Bartusek and Dakshita Khurana and Nishant Kumar},