Directed related to our work, in the article [12] the authors Rajagopal Nagarajan, Nikolaos Papanikolaou, Garry Bowen and Simon Gay introduce the use of computer-aided verification as a practical means for analysing the QKD protocol BB84. based on probabilistic model-checking approach, they have used the PRISM model-checker to show that, the equivocation of the eavesdropper with respect to the channel decreases exponentially as the number of qubits transmitted in BB84 is increased. They have also shown that the probability of detecting the presence of an eavesdropper increases exponentially when the number of qubits.