Security of quantum key distributions with entangled qudits

Abstract

The generality of Ekert's entanglement-based cryptographic protocol where qubits were relaced by N or d-dimensional system was presented. The information gained by a potential eavesdropper was derived, to study its robustness against optimal incoherent attacks, during a cloning -based individual attack. It was shown that the accepatable error rate of the N-DEB protocol increases with the dimension N. It was found that the maximal error rate provides a good qualitative measure of the security of the protocol.