摘要：Delay/disruption tolerant network adopts a storecarry-and-forward mechanism, of which all the participantsare assumed to cooperate with one another in messagedelivery, to overcome the challenges of the intermittentconnection and the time-varying network topology. Unfortunately,there are always some nodes deviating from the rulesin order to save their own precious resources. To address theselfishness and the security problems, we propose a securemessage transaction protocol for delay tolerant networks, inwhich the messages are encrypted by the source nodes andauthorized by the TTP before they are propagated in thenetworks. The signatures are aggregated sequentially by thesource node and the subsequent forwarders. The aggregatedsignatures record the message delivery paths. By checkingthe signatures aggregated so far, the intermediate nodes canbe sure of the message authenticity and decide whether todeliver the messages to the next hops or not. Thus, thefree riding attacks and path forging attacks are prevented.Furthermore, the payment mechanism of the proposedscheme makes the participants have no incentive to launchthe collusion attacks in the path disclosure. In addition, thehash binary tree is harnessed to decrease the number ofauthorization times when fragmentation is invoked at thesource, and the relationship between the delivery overheadand the authorization times is presented. In the proposedscheme, the cipher computation and bundle envelopment canbe performed off-line, without the information of next hops,while the DTN nodes are driving freely without any DTNconnections. Performance analysis and simulation resultsprove that this off-line computing design is efficient in termsof delivery ratio and delivery speed.
