Figure 7

Fidelity between legitimate QMAC \(\vert \mathrm{QMAC} \rangle _{i} = \mathcal{R}_{k_{AB}^{i}} ( {\pi} / {2} ) \vert \psi _{i} \rangle \) and Eve’s QMAC \(\vert \mathrm{QMAC}_{\mathrm{E}} \rangle _{i} = \mathcal{R}_{E^{i}} ( {\pi} / {2} ) \vert \psi _{E^{i}} \rangle \) on (a) 3D, and (b) 2D contour plot. \(\theta _{E^{i}}\) and \(\phi _{E^{i}}\) are the polar and azimuthal angles of the secret key \(E^{i}\) estimated by Eve, respectively