Completely Device Independent Quantum Key Distribution

TL;DR

This paper introduces a method for device-independent quantum key distribution that eliminates the need for initial randomness seeds by leveraging secret messages, simplifying secure quantum communication.

Contribution

It demonstrates that secret messages can replace randomness seeds in DIQKD, reducing assumptions and enhancing practical secure quantum communication.

Findings

Secret messages can replace randomness seeds in DIQKD.

The protocol is secure under the assumption that messages are unknown to adversaries.

This approach broadens the applicability of DIQKD in real-world scenarios.

Abstract

Quantum key distribution (QKD) is a provably secure way for two distant parties to establish a common secret key, which then can be used in a classical cryptographic scheme. Using quantum entanglement, one can reduce the necessary assumptions that the parties have to make about their devices, giving rise to device-independent QKD (DIQKD). However, in all existing protocols to date the parties need to have an initial (at least partially) random seed as a resource. In this work, we show that this requirement can be dropped. Using recent advances in the fields of randomness amplification and randomness expansion, we demonstrate that it is sufficient for the message the parties want to communicate to be (partially) unknown to the adversaries -- an assumption without which any type of cryptography would be pointless to begin with. One party can use her secret message to locally generate a secret sequence of bits, which can then be openly used by herself and the other party in a DIQKD protocol. Hence, our work reduces the requirements needed to perform secure DIQKD and establish safe communication.