Reverse reconciliation protocols for quantum cryptography with continuous variables

TL;DR

This paper presents new continuous-variable quantum key distribution protocols that are secure against individual attacks, do not require entanglement or quantum memories, and can be implemented with coherent states and homodyne detection, potentially improving efficiency.

Contribution

The authors introduce practical CV-QKD protocols secure against individual attacks without needing entanglement or quantum memories, expanding implementation options.

Findings

Protocols are secure for any optical transmission

No need for squeezing, entanglement, or quantum memories

Potentially more efficient than discrete-variable protocols

Abstract

We introduce new quantum key distribution protocols using quantum continuous variables, that are secure against individual attacks for any transmission of the optical line between Alice and Bob. In particular, it is not required that this transmission is larger than 50 %. Though squeezing or entanglement may be helpful, they are not required, and there is no need for quantum memories or entanglement purification. These protocols can thus be implemented using coherent states and homodyne detection, and they may be more efficient than usual protocols using quantum discrete variables.