III. BLACK HOLE IN MANETIn the black hole attack, the malicious nodes absorb all the data, transmitted from the source node to the destination while forwarding the data to the next node. In the AODV protocol, the black hole attack is classified into two categories: black hole attack caused by RREP and black hole attack caused by RREQ.A. Black hole attack caused by RREQThe following things happen when black hole attack is formed by malicious nodes or an attacker while sending fake RREQ messages: • Attacker changes the source IP address to RREQ with the IP address of the source node. • The attacker changes the destination IP address in RREQ to the IP address of the destination node. • The attacker changes the source IP address of the IP header to his own IP address. • The attacker changes the destination IP address of the IP header to a broadcast address. • Choose a high sequence number and a low hop number and enter them into related fields in RREQ. Then, the attacker inserts the incorrect source node information into the routing table of nodes that receive a fake RREQ message. So, if these nodes send data to the source, in the first phase they send it to...