We propose an efficient scheme for sharing a continuous-variable quantum secret using passive optical interferometry and squeezers: this efficiency is achieved by showing that a maximum of two squeezers is required to extract the secret state, and we obtain the cheapest configuration in terms of total squeezing cost. Squeezing is a cost for the dealer of the secret as well as for the receivers, and we quantify limitations to the fidelity of the extracted secret state in terms of the squeezing employed by the dealer.
- quantum information
- quantum cryptography
- quantum state engineering and measurements