Hybrid key management for mobile ad hoc networks

Many public key infrastructure (PKI) approaches have been proposed in the,recent years to secure mobile ad hoc networks (MANETs). We present a new hybrid key management infrastructure, which combines the concepts of PKIs for MANET with trusted-third-party based infrastructures. In our hybrid approach, the underlying PKI is merely used to set-up initial trust of nodes in a MANET, and, thus, generate a random trust graph connecting all the nodes of the MANET. Then, MANET nodes cooperate to securely distribute trust information and symmetric keys to other nodes through the shortest trust path. The hybrid key management infrastructure enables the same security services as a normal PKI yet key establishment and node-to-node authentication, as demonstrated by our performance analysis, is substantially improved in terms of computational and communication efficiency. We also discuss the security level of the hybrid approach.