The first step is to identify the main objective behind the use of AHP, criteria, sub-criteria, and set of alternative choices used for the comparison. The alternatives are actually leafs of the tree and the objective corresponds to the root. For instance, Figure 5 shows the hierarchy we used for ranking the security algorithms. Table 1 shows criteria we used in SecMan, but the list can be extended with other factors. Some metric values such as the delay for the network cost or the cryptographic throughput are specific to the system cost and the testbed we used when we measured these parameters (cf. last section)