# Teleportation-based continuous variable quantum cryptography

## Abstract

We present a continuous variable (CV) quantum key distribution (QKD) scheme based on the CV quantum teleportation of coherent states that yields a raw secret key made up of discrete variables for both Alice and Bob. This protocol preserves the efficient detection schemes of current CV technology (no single-photon detection techniques) and, at the same time, has efficient error correction and privacy amplification schemes due to the binary modulation of the key. We show that for a certain type of incoherent attack, it is secure for almost any value of the transmittance of the optical line used by Alice to share entangled two-mode squeezed states with Bob (no 3 dB or 50% loss limitation characteristic of beam splitting attacks). The present CVQKD protocol works deterministically (no postselection needed) with efficient direct reconciliation techniques (no reverse reconciliation) in order to generate a secure key and beyond the 50% loss case at the incoherent attack level.

## Keywords

Quantum communication Quantum cryptography Quantum teleportation## Notes

### Acknowledgements

FSL and GR thank CNPq (Brazilian National Council for Scientific and Technological Development) for funding and GR thanks CNPq/FAPESP (State of São Paulo Research Foundation) for financial support through the National Institute of Science and Technology for Quantum Information.

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