Covert Entanglement Generation and Secrecy
This work provides fundamental limits for covert quantum communication, which is important for ensuring undetectable quantum information transmission in adversarial settings.
The paper determines the covert capacity for entanglement generation over a noisy quantum channel, showing that O(√n) EPR pairs can be distributed covertly and reliably over n channel uses, and derives single-letter expressions for covert secrecy and entanglement-generation capacities.
We determine the covert capacity for entanglement generation over a noisy quantum channel. While secrecy guarantees that the transmitted information remains inaccessible to an adversary, covert communication ensures that the transmission itself remains undetectable. The entanglement dimension follows a square root law (SRL) in the covert setting, i.e., $O(\sqrt{n})$ Einstein-Podolsky-Rosen (EPR) pairs can be distributed covertly and reliably over $n$ channel uses. We begin with covert communication of classical information under a secrecy constraint. We then leverage this result to construct a coding scheme for covert entanglement generation. Single-letter expressions are derived for the covert key-assisted and unassisted secrecy capacities, as well as for the covert entanglement-generation capacity.