  In this paper, we generalize the secure quantum information exchange (SQIE)
protocol, originally proposed by the authors [J. Phys. B: At. Mol. Opt. Phys.
44 (2011) 115504] for secure exchange of one qubit information with each of
Alice and Bob, to the case of secure exchange of quantum information of
arbitrary qubits with Alice and Bob. We also discuss security of the original
and generalized SQIE protocols with respect to the number of qubits with
controller, Charlie.
