Abstract: A wireless network is method by which homes, telecommunications network and business enterprise installations, avoid the costly process of introducing the cables or connection between various equipment locations. Mobile ad hoc networks are an infrastructure less internet protocol based network. The absence of centralized firewall and distributed nature of operation of nodes make MANETS vulnerable to malicious attacks. In this case, it is crucial to develop efficient intrusion-detection mechanisms to protect MANET from attacks. With the improvements of the technology and cut in hardware costs, we are witnessing a current trend of expanding MANETs into industrial applications. To adjust to such trend, it is vital to address its potential security issues. In this paper, we propose and implement a new intrusion-detection system named Enhanced Adaptive Acknowledgment (EAACK) specially designed for MANETs. Compared to contemporary approaches, EAACK demonstrates higher malicious behavior detection rates in certain circumstances while does not greatly affect the network performances

Keywords: Digital signature, digital signature algorithm (DSA), Enhanced Adaptive Acknowledgment (AACK) (EAACK), Mobile Ad hoc Network (MANET).