Nodes in Mobile Ad-hoc NETworks (MANETs) communicate each other using the wireless transmission. Many protocols have been proposed allowing the establishment of multi-hop paths to connect source and destination nodes. The absence of a physical link between the nodes and the multi-hop routing lead to a lack of security. Different typologies of attack effective against MANETs have been investigated thoroughly, and many solutions have been proposed to take the required countermeasures. Many of them are based on the cryptography, protecting data with digital signatures and hash chains, but they are not useful when a fair node is compromised later in time.