Quantum nonlocality as the route for ever-lasting unconditionally secure bit commitment
This addresses the challenge of secure bit commitment in cryptography, offering potential improvements over existing protocols, though it is incremental as security is not rigorously proved.
The authors tackled the problem of achieving unconditionally secure bit commitment by proposing a protocol based on quantum nonlocality, which appears to provide ever-lasting security through physical arguments and numerical simulations, circumventing previous impossibility proofs by forcing the proof to become classical data.
We present a bit commitment protocol based on quantum nonlocality that seems to bring ever-lasting unconditional security. Although security is not rigorously proved, physical arguments and numerical simulations support this conclusion. The key point is that the proof of the commitment is forced to become classical data uncorrelated with anything else. This allows us to circumvent previous impossibility proofs in which it is assumed that classical data can be replaced by quantum data that may be entangled with the committer. The proposed protocol also recovers two features missing in recent "relativistic" quantum bit commitment protocols: (i) the committer can decide if and when she wants to reveal the commitment and (ii) the security of the commitment lasts for arbitrary long time.