Abstract

Splitting a secret message in the way that a single person is not able to reconstruct it is a common task in information processing and high security applications. For instance, let us assume that the launch sequence of a nuclear missile is protected by a secret code and it should be ensured that a single person is not able to activate it but at least two persons need to cooperate in order to carry out the launch. Another example is a joined banking account. The account is set in such a way that withdrawing cash is possible when all of parties cooperate by generating a code required by an automated teller machine (ATM) or by a banker. A solution for this problem and its generalization, including several variations, is provided by classical cryptography and is called secret sharing. It consists of a way of splitting the message using mathematical algorithms and the distribution of the resulting pieces to two or more legitimate users by classical communication. However, all ways of classical communication currently used are susceptible to eavesdropping attacks. As the usage of quantum resources can lead to unconditionally secure communication, a protocol introducing quantum information scheme to Secret Sharing has been developed. This protocol provides information splitting and eavesdropping protection. However, his scheme is in practice non-scalable since it used multipartite entangled states that are difficult to generate and transmit. Furthermore the use of polarization encoding is impractical for applications over commercial birefringent single mode fibers (SMF) networks. A new protocol solving the above mentioned problems was proposed in [1]. The protocol requires only a single qubit for quantum information transmission, which allowed for its practical experimental realization and scalability.

© 2009 IEEE