Improving the efficiency of entanglement based quantum key exchange

This article presents two efficient cryptographic protocols, based on quantum entanglement, for secure exchange of secret keys. While the first protocol requires storage of entangled qubits, the second protocol has no storage requirements and presents a probabilistic model. We show that there is a tradeoff between security against eavesdropping and the efficiency of the protocol in terms of usable bits available for the secret key. This security parameter s can be varied by the communicating parties based on practical considerations.