Eavesdropping on the “ping-pong” type quantum communication protocols with invisible photon

The crucial issue of quantum communication protocol is its security. A quantum communication scheme must be based on the existing or nearly existing technology, but its security must be guaranteed against an eavesdropper whose technology is limited only by the laws of quantum mechanics. In this paper, we show that all the deterministic and direct two-way quantum communication protocols, sometimes called ping-pong (PP) protocols, are insecure when the eavesdropper uses the invisible photon eavesdropping (IPE) scheme to eavesdrop on the communication. In this IPE scheme, an eavesdropper can obtain full information of the communication with zero risk of being detected. Finally, we discuss the possible modification of PP-type protocols.