Quantum Cryptography using Bound Entangled State

Abstract

In this thesis we have found new class of bound entangled state that are key distillable. We have shown that in certain cases ltration operation which has a mapping !L LyTrL L y= 0 increases the lower bound KDWDof key ditillation value. The di erence between the values of KDWD before and after the ltration protocol can be seen in gure 4:3. We have de ned certain condition that were proposed in ([1]) and showed that even after violation of these condition, we can prove key distillability of bound entangled state using ltration operation.