Black hole attack refers an attack by single or more number of malicious nodes which forcibly captures the route from source to destination by sending reply with largest sequence number and smallest hop count. In this paper, a novel technique using Localized Secure Architecture for MANET (LSAM) routing protocol is proposed to detect and prevent co-operative black hole attack. Security Monitoring Nodes (SMNs) would be activated only if the threshold value is exceeded. If malicious nodes are detected, other SMNs in its proximity area are intimated to isolate the malicious nodes. Network simulator tool is implemented to analyze the network performance of different scenarios with various number of nodes. Packet delivery ratio (PDR), routing overhead, control overhead, packet drop rate, throughput and end-to-end delay (EED) are the factors taken into consideration for performance analysis and it is shown that the proposed protocol is more secured and efficient. PDR is been increased by 27 % in the presence of 40 % misbehaving nodes, while it increases the percentage of overhead on proposed routing protocol from 1 to 4 %. EED is greatly reduced from 0.9 to 0.3 % in LSAM.