Can relativistic bit commitment lead to secure quantum oblivious transfer?

TL;DR

This paper investigates whether relativistic bit commitment can enable secure quantum oblivious transfer, revealing that some no-go proofs still apply while others do not, depending on the protocol models.

Contribution

It provides a detailed analysis of the potential and limitations of using relativistic bit commitment for secure quantum oblivious transfer, highlighting which no-go proofs remain valid.

Findings

Some no-go proofs still apply, allowing increased reliability for the receiver.

Certain no-go proofs are invalid due to overly idealized protocol models.

Relativistic BC can partially enable secure QOT but faces fundamental limitations.

Abstract

While unconditionally secure bit commitment (BC) is considered impossible within the quantum framework, it can be obtained under relativistic or experimental constraints. Here we study whether such BC can lead to secure quantum oblivious transfer (QOT). The answer is not completely negative. On one hand, we provide a detailed cheating strategy, showing that the "honest-but-curious adversaries" in some of the existing no-go proofs on QOT still apply even if secure BC is used, enabling the receiver to increase the average reliability of the decoded value of the transferred bit. On the other hand, it is also found that some other no-go proofs claiming that a dishonest receiver can always decode all transferred bits simultaneously with reliability 100% become invalid in this scenario, because their models of cryptographic protocols are too ideal to cover such a BC-based QOT.