Trust relationships change frequently in ad-hoc networks, so it is difficult to build certification paths among their nodes. When trust relationships are bidirectional, certification path discovery becomes more difficult because multiple paths can exist between two entities and all the options do not lead to the target entity. On the other hand, certificates can establish relationships of different trust level. In this paper, we propose a protocol that establishes a virtual hierarchy from a peer-to-peer web of trust. This protocol uses swarm intelligence to obtain information about the certification paths and to establish the trustworthiness of each node. Our protocol does not require to issue new certificates among network entities, facilitates the certification path discovery process and the maximum path length can be adapted to the characteristics of users with limited processing and storage capacity.