This book presents a new trust based light weight authentication routing protocol. In this approach, the secure path is established based on the node¿s trust value and this trust is measured based on packet success ratio (PSR). If the trust value of any node is below threshold value, then it is authenticated using the secret sharing technique. This authentication technique enhances the reliability, redundancy and network lifetime.To achieve data confidentiality and integrity a new secure multipath routing and data transmission protocol presented. This protocol accomplished a digitally signed Route Request (RREQ) at every source node to find a secure route towards the destination node. The choosing of the next node in every path is based on these signatures only.A Certificate Authority Distribution and Trust based Threshold Revocation method is developed. Based on the Certificate distribution and threshold revocation, the nodes which are malicious can be detected by its neighbour nodes.The officials of the certificate distribute the secret key to all nodes. Following, a threshold revocation technique based on confidence is calculated. Here the nodes of misbehavior are removed.