Message-Falsification Prevention With Small Quantum Mask in Quaternary Y00 Protocol

Confidentiality, integrity, and availability constitute the triad of cybersecurity. Confidentiality is the property of invisibility against unauthorized parties. Integrity is protecting data from being altered or falsified by unauthorized parties, and availability is the accessibility of data to legitimate parties whenever they need it. However, in quantum cryptography, confidentiality is of central interest, while the latter two are often overlooked. In contrast, the Y00 protocol has an affinity for the conventional optical infrastructure. Therefore, its availability is the same as that of the current optical network. Moreover, the previous work showed that the quaternary Y00 protocol could prevent message falsification to satisfy integrity. This paper proposes a new implementation that uses a quantum mask size reduced to 4 levels from 24 levels that was required in the previous work. This smaller mask is sufficient to prevent the attacker's falsified messages in the middle of the communication line at will, even if she knows the full message. Therefore, the attacker fails to falsify the message with a probability of almost 100% per byte.