| 研究実績の概要 |
The main study of the research plan was to develop the new protocols of secure quantum communication, which have practical significance.
1. We introduced a notion of asymmetric quantum dialogue (AQD) protocol, which provides the different amount of communication powers to Alice and Bob. The proposed scheme, offers an architecture, where the entangled state and the encoding scheme to be shared between Alice and Bob depends on the amount of classical information they want to exchange with each other.
2. Semi-quantum protocols are proposed for key agreement, controlled deterministic secure
communication and dialogue, with optimal/minimal nonclassical resources, and with their potential applications. Specifically, these schemes show less quantum resources are required than the existing fully quantum protocols because in semi-quantum cryptography, one of the users is classical. This study has established that almost every secure communication and computation tasks that can be performed using fully quantum protocols can also be performed in semi-quantum manner.
3. A notion of quantum conference (QC) is introduced. QC is defined as a multiparty secure communication task that allows each party to communicate their messages simultaneously to all other parties in a secure manner using quantum resources. It is shown that the proposed protocols can be realized using a large number of entangled states and group of operators.
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