Arbitrarily long relativistic bit commitment
This addresses a key bottleneck in quantum cryptography for secure communication, offering a significant practical improvement over prior work.
The paper tackled the problem of improving the security and practicality of a relativistic bit commitment protocol by analyzing its scaling with commitment time, showing that the complexity scales linearly rather than double-exponentially, enabling arbitrarily long commitments with classical communication and computation.
We consider the recent relativistic bit commitment protocol introduced by Lunghi et al. [Phys. Rev. Lett. 2015] and present a new security analysis against classical attacks. In particular, while the initial complexity of the protocol scaled double-exponentially with the commitment time, our analysis shows that the correct dependence is only linear. This has dramatic implications in terms of implementation: in particular, the commitment time can easily be made arbitrarily long, by only requiring both parties to communicate classically and perform efficient classical computation.