Reduced randomness in quantum cryptography with sequences of qubits encoded in the same basis

L. -P. Lamoureux, H. Bechmann-Pasquinucci, N. J. Cerf +2

We consider the cloning of sequences of qubits prepared in the states used in the BB84 or 6-state quantum cryptography protocol, and show that the single-qubit fidelity is unaffect…