Extending the collaboration boundary in localized threshold cryptography-based schemes for MANETs

Security schemes based on threshold cryptography approaches proposed for Mobile Ad-Hoc Networks (MANETs) normally offer localized security services. Thus, their operation relies solely on the collaboration of at least the threshold number of directly connected shareholders to the service requestor. Due to the unpredictable and dynamic connectivity in MANETs, the availability of a sufficient number of local shareholders cannot be guaranteed. This can severely interrupt the availability of the services in such schemes. Therefore, we propose an Extended Threshold Cryptography-based Scheme (XTC) for MANETs to sustain the service availability in localized schemes when the number of the local shareholders available to serve a requestor is below the threshold. XTC extends the collaboration boundary from single-hop shareholders to multi-hop shareholders linearly when necessary until the threshold number of the discovered shareholders is achieved. We also provide the computation of message complexity for the algorithm of the proposed scheme.