Research On Security Technology For Mobile P2P Networks

MP2P network, which can meet the demand of sharing files and information anytime andanywhere, has a promising application future in file-sharing, mobile social network, e-commerceand other location based services. However, attacks launched by malicious peers may disturb thesystem and imperil users’ privacy. What’s more, different attacking means can be integratedtogether, which adds the difficulty of attack detecting. The main shortages of the existingsecurity mechanisms are as follows: Firstly, there is a lack of topology construction andmaintenance protocol to meet the demand of security requirements. Secondly, robust trust modelis in demand to handle active attacks especially that with dynamic strategy. At last, mutualanonymous mechanism is needed to protect users’ sensitive information from being exposed.Therefore, this dissertation is devoted to researching on the security issues for MP2P networks.Based on the analysis of security issues from different aspects, a topology construction andmaintenance protocol considering security requirements is proposed. Then a distributed trustmodel and a mutual anonymous communication mechanism are designed to handle active andpassive attacks for MP2P networks.The main achievements of this dissertation can be outlined as follows:1. A PDG-based secure topology constructing and maintaining protocol (PDGSTP) isproposed. To meet the demand of ID distributing security, preventing Churn and defendingtopology mismatch, a secure topology construction protocol based on PDG(2) is proposed, inwhich supernodes have invariable link digree. Routing methods of supernodes within andbetween domains are designed to retrieving cost. Supernodes backup policy is designed toguarantee the usability of ordinary nodes when the current supernode is disabled. Neighbordetecting and updating policy handles the mismatch problem under dynamic condition. Boththeoretical analysis and simulation results show that PDGSTP can meet the demand of safetyrequests and reduce the cost of topology constructing and maintaining.2. A distributed trust model based on social distance (SD2Trust) is established. SD2Trustdifferentiates the reliability of recommending and that of service providing, and describes nodes’status and behavior character by structural vectors. By constructing trustworthy node set andcomputing reputation calculating weights according to social similarity, SD2Trust model can getrid of the effect of self-promoting and slandering, resist attacks that using strategy. Thedistributed reputation storing structure and additional incentive approach together make it moresuitable to mobile environment. Both theoretical analysis and simulation results show thatSD2Trust can resist dynamic attacks with strategy and improve the success rate of innocent nodeselecting.3. An adaptive mutual anonymous communication mechanism (AMACM) is proposed.Firstly, NCS-Crowds algorithm is designed to realize sender anonymity, which dynamiclychooses different policies to forward messages according to the current network condition. Toguarantee the success rate of anonymous communication, forwarding node selects forwardingnodes according to the direct reputation from SD2Trust. By means of synthesizing pseudonym mapping, spurious flows and PKI together, an adaptive mutual anonymous communicationmechanism is proposed to protect users’ communication privacy. Theoretical analysis andsimulation results show that AMACM can achieve mutual anonymous communication withcertain cost.