Quantum bit commitment and the reality of the quantum state

Abstract

Quantum bit commitment (QBC) is insecure in the standard non-relativistic quantum cryptographic framework, essentially because Alice can exploit quantum steering to defer making her commitment. Two assumptions in this framework are that: (a) Alice knows the ensembles of evidence $E$ corresponding to either commitment; and (b) system $E$ is quantum rather than classical. Here, we show how relaxing assumption (a) or (b) can render her malicious steering operation indeterminable or inexistent, respectively. Finally, we present a secure protocol that relaxes both assumptions in a quantum teleportation setting. Without appeal to an ontological framework, we argue that the protocol's security entails the reality of the quantum state, provided retrocausality is excluded.

10 pages, 2 figures; close to the published version

References in corpus (6)

• Steering, Entanglement, Nonlocality, and the EPR Paradox
• Testing spooky action at a distance
• Is the quantum state real? An extended review of $\psi$-ontology theorems
• Asymptotic teleportation scheme as a universal programmable quantum processor
• Quantum teleportation scheme by selecting one of multiple output ports
• Security bound of cheat sensitive quantum bit commitment

Cited by in corpus (2)

• Unconditionally secure quantum bit commitment based on the uncertainty principle
• An optical implementation of quantum bit commitment using infinite-dimensional systems