An approach to the unconditional security of quantum key distribution protocols is presented, which is based on the uncertainty principle. The approach applies to every case that has been treated via the argument by Shor and Preskill, but it is not necessary to find quantum error correcting codes. It can also treat the cases with uncharacterized apparatuses. The proof can be applied to cases wh...

We devise a simple modification that essentially doubles the efficiency of the BB84 quantum key distribution scheme proposed by Bennett and Brassard. We also prove the security of our modified scheme against the most general eavesdropping attack that is allowed by the laws of physics. The first major ingredient of our scheme is the assignment of significantly different probabilities to the diff...

We devise a simple modification that essentially doubles the efficiency of a well-known quantum key distribution scheme proposed by Bennett and Brassard (BB84). Our scheme assigns significantly different probabilities for the different polarization bases during both transmission and reception to reduce the fraction of discarded data. The actual probabilities used in the scheme are announced in ...

We give an entanglement assisted scheme for quantum key distribution. The scheme requires the maximally entangled 2-qubit state but does not require any quantum storage. Given the symmetric noisy channel, our scheme can tolerate the bit error rate up to 26% in the 4-state case and 30% in the 6-state respectively, respectively. These values are higher than those of all currently known two-level-...

This paper investigates an efficient and practical information reconciliation method in the case where two parties have access to correlated continuous random variables. We show that reconciliation is a special case of channel coding and that existing coded modulation techniques can be adapted for reconciliation. We describe an explicit reconciliation method based on LDPC codes in the case of c...

administrative regulations for water flow decrease distribution efficiency and effect the economical operation of irrigation networks. complications in distribution systems and the decrease in availability of water require study of the hydraulic performance of existing flow control structures. control systems designed by neyrpic (zayandeh rud network) and usbr (doroodzan network) were investiga...

We introduce a generalization of Hadamard and the controlled not gates which together with the generalized Bell states, enable us to introduce new methods for quantum key distribution (QKD) of d-level quantum states (qudits). In case of eavesdropping, an error rate of d−1 d is introduced in Bob’s received qudits, so that for large d, comparison of only a tiny fraction of received qudits with th...

Corresponding Author: Es-said Chanigui Department of Mathematics and Computer Science, FSO, University Mohamed I, Oujda, Morocco Email: [email protected] Abstract: This study provides a simple variation of the protocol of quantum key expansion proposed by Hwang. Some weaknesses relating to the step of public discussions for error detection are analyzed and an attack strategy, allowing the eaves...