Study On Partially Blind Signature And Its Application In Participatory Sensing

With the development of mobile communication techniques in recent years,various intelligent devices have become an indispensable part of our daily life.As the innovation of electronic manufacturing industry,these intelligent devices are equipped with various sensors.Because of the initiative of people who carry these devices,participatory sensing emerges at the right time,which can be regarded as a new application of wireless sensor networks.In participatory sensing system,sensing data is directly collected through the sensors in mobile devices by participants,and then uploaded to the data requester.There have been many applications using sensing data,such as building a noise map,monitoring traffic conditions and so on,which can help improve people's daily life.However,there are two factors that hinder the development of participatory sensing technology: first,the sensing data contributed by the users' devices may be exploited by adversaries to obtain private information about the participants.Besides,in order to participate in sensing tasks,users have to trigger sensors to collect data and uploaded it through networks,which may consume power of devices and network data quota.If the consumption cannot be balanced,the users' participation enthusiasm will be greatly affected.To motivate participatory sensing,both obstacles of privacy and incentives should be addressed.Firstly,some attacking methods for users' privacy in participatory sensing are introduced in this thesis.According to the research on privacy preservation technology,some efficient countermeasures of these threats are introduced,including statistical grouping technology,trusted third party verification technology,k-anonymity technology and digital cryptogram technology,in which digital cryptogram technology is chosen as research emphasis of this thesis.Based on elliptic curve public key cryptography,a new certificateless partially blind signature scheme is proposed.It is proved that the new scheme is secure in random oracle model.Moreover,Because of not using complex bilinear pairing operation,our scheme outperforms some previous schemes on computational efficiency significantly.Secondly,a pseudonym management scheme is proposed,in which the disclosing of a pseudonym is separated from its tracking to avoid the risk of authorities' compromise.In order to ensure that requester's real identity is only visible to certificate authority rather than pseudonym certificate authority,partially blind signature is used to issue pseudonym certificates.Even if the two authorities compromise with each other,it is impossible for them to correlate a pseudonym to its requester.In addition,if a pseudonym is used illegally,the real identity of the pseudonym user can be directly analyzed by tracking authority without any help of other authorities.Performance analysis shows that the scheme is superior to existing schemes in terms of operational efficiency and privacy preservation.Finally,we proposed a privacy-aware incentive scheme in which no trusted third party is involved.By taking into account the threats and deficiency in participatory sensing,partially blind signature and pseudonym technology are deployed to guarantee the implementation of incentive and preservation of privacy.Security analysis shows that the attackers can neither infer the certain sensing task from an incentive nor combine the certain participator's real identity with a sensing task report,even without help of a trusted third party.From the performance evaluation,it is clear that in the certain number of credits,the scheme allows each user to earn incentive efficiently.