International Journal of Innovative Technology and Exploring Engineering (IJITEE) ISSN: 2278-3075, Volume-9 Issue-3, January 2020 3299 Published By: Blue Eyes Intelligence Engineering & Sciences Publication Retrieval Number: C9035019320/2020©BEIESP DOI: 10.35940/ijitee.C9035.019320 Abstract: Mobile Ad hoc network is a temporary network. It helps to communicate two or more devices for short range. Routing Protocols are use to establish a communication in MANET. As it is a open network , it has many vulnerabilities from security point. Black hole Attack is one of the major concern in MANET. In this paper, we have implemented Black hole Attack in random mobility environment and analyse its impact on MANET using various parameters for single and multiple connection in MANET. Black hole attack disturbs one of the connection in the network while remaining connection are unaffected. During our analysis, we found that performance result of black hole attack in multiple connection network give a similar kind of output mentioned in various research paper related to gray hole attack, which will make difficult to analysis the type of attack in the network. Keywords : MANET; Routing Protocols; AODV; Random Mobility; Security; Black hole Attack I. INTRODUCTION Mobile Ad hoc Networkis a short range network used for device to device communication. The device which are also called as a node, does not require any router in the middle of source and destination. The neighbouring node its-self acts as intermediate node and forms a small network. The communication can be single or multiple communication in the network. Routing protocol provide the shortest path between the two communicating nodes. There are different routing protocols proposed in MANET based on the type of network. This type of small networks are open to many security threats. Black hole attack is a common threat which reduce the performance of the network II. AD HOC ON-DEMAND DISTANCE VECTOR (AODV) AODV falls under the category of reactive routing protocols, which finds the shortest path and broadcast RREQ (Route to Request) packet when the communication between the nodes is required. Revised Manuscript Received on January 5, 2020 * Correspondence Author Sharma Hitesh Omprakash, Student, GTU Graduate School of Engineering and Technology, Gandhinagar, India. Email: hiteshsharma720@gmail.com Margam K. Suthar, Assistant Professor, Gujarat Technological University, Ahmedabad, India. Email: ap_1mcwt@gtu.edu.in As shown in the (Fig.1), Source node which is Node S, broadcast RREQ packet to find the path for the destination node which is Node D. If the neighbouring node does not have the destination node, it forwards the RREQ packet and also stores the path of the RREQ packet. When destination receives the RREQ packet, it forwards a RREP (Route to Reply) packet in the inverse direction of the same path of RREQ packet by selecting the shortest path. Once the communication is established, the destination node start receiving the data packet from thesource node. Fig. 1.AODV Protocol broadcasting RREQ and RREP III. BLACK HOLE ATTACK Node which does not work like a trusted node and either drop the packets or forward to the unknown node can be considered s malicious node. Black hole node initially sends the fake RREP to the source node during the connection establishing process as a shortest node to the destination. When the source node start sending the data packet after establishing the connection via black hole node, then it does not forward the packets to the destination and start dropping all the packets. Implementation of Black hole Attack for Random Mobility for Single and Multiple Connection in MANET Sharma Hitesh Omprakash, Margam K. Suthar