An entanglement-based quantum key distribution protocol

A novel quantum key distribution protocol using entanglement is presented. In this protocol, the stream of qubits is divided up into a sequence of qubit pairs. It is shown that by entangling the qubits in each qubit pair by randomly applying one of the two predefined unitary transformations before transmission, the protocol reveals less information about the key bit than the BB84 protocol, and the quantum bit error rate is also reduced.