# FuGeF: A Resource Bound Secure Forwarding Protocol for Wireless Sensor Networks
## 2 Related Works
The GREES selection criteria use parameters such as channel link condition, packet progress to a destination, residual energy of node and environmental energy supply for next hop selection. The next hop node was computed based on GREES-L and GREES-M. The GREES-L and the GREES-M utilize the linear and multiplicative functions of the parameters (respectively) in order to balance the geographical advance efficiency per packet transmission and the availability of receiving nodes. The protocol achieved the increase in energy efficiency and packet delivery at the expense of increase in end to end delay. However, the GREES was unable to balance between geographical advance efficiency per packet transmission and the availability of receiving nodes because packets may have to travel along some links of weaker quality or travel longer hops to get to their destinations. In [23], a Multi-Criteria Decision Analysis (MCDA) based method for optimization was adopted for node selection. Multi-Criteria Decision Routing protocol (MCDR) was proposed to improve on the longevity of the network and traffic distribution. It employs distance and remaining energy as criteria for node selection. The approach achieves node selection by the addition of criterion values after each criterion was multiplied with a fixed value known as a weight. However, the flexibility in weight assignment affects the optimization process, causing output utilized for node selection to skew towards an intended objective due to an assigned weight value. This hinders other performance metrics as they tend to portray a poor trade-off in the metrics. Some earlier works employed the use of Computational Intelligent Systems (CIS) for node selection. Among the numerous CIS, Fuzzy logic system (FLS) has emerged as one of the most commonly used decision-making algorithms to improve network performance. The FLS, which is based on mathematical proofs, accepts values (parameter) from nodes as inputs, where it computes and infers output values. The computation involves converting input values (crisp input) into a fuzzy set and processing it using a series of IF-THEN rules, which are intended to mimic human reasoning. The processed fuzzy set is converted back into output values (crisp output). In most cases, the node with the highest output value is selected as the next hop node. This fuzzy logic based node selection strategy is utilized in protocols such as SFRRP [24], DSR [25], BCFL [26], FMAR [27], NORIA [28], and [29], to mention a few. The flexibility in the choices of input parameters for the FLS makes it tuneable and adaptive to different application needs, thus, improving the targeted performance metrics. On the other hand, improper selection of these parameters may hinder or cause unbalanced performance between metrics, resulting in poor performance of the network. Despite attempts to optimize trade-offs in performance metrics of these protocols, only a few of the protocols considered were intended for security purposes. This is because the security mechanisms in protocols demand higher utilization of the constrained sensor resources (which if depleted, may compromise the entire network performance). Resource bound security solutions proposed the alteration of protocol routing semantics to implement security mechanisms which impedes the effect of attacks on a network as well as maintains optimal performance. This improved approach is seen in SBGR [11], SIGF [2] and DWSIGF [3] routing protocols mentioned earlier. The Resource bound security approach is among the first few attempts that were proposed to provide a better trade-off between security and performance of a protocol. SBGR [11] was proposed to mitigate Sinkhole and Sybil attacks in a network. It employs the MFR forwarding strategy for node selection as well as other improvements in the protocol semantics for its security operation.