The Research Of Secure Communication And Access Control In IoT Environment

In the last few years,the popularity of the Internet and the mobile Internet and the devel-opment of the electronic information technology are bringing us into the fifth scientific and technological revolution-the wave of the Internet of Things(IoT).Although the IoT is still in the embryonic stage,many innovative research results have emerged in its sub fields,such as VANETs,mobile medical,big data and cloud computing.In the research on the IoT,the security issue has always been an important subtopic for researchers.For instance,there are lots of vehicles moving fast in VANETs,which is a significant difference from common networks.Therefore,it is not easy to take both security and efficiency into consideration in the process of data transmission.The existing security protocols for VANETs mainly focus on data integrity rather than confidentiality,which is not reasonable in some cas-es.Moreover,the computational efficiency of these protocols will decrease rapidly with the growth of data when VANETs are integrated into the IoT.In addition,as an indispensable part of the IoT,cloud computing involves in many security issues caused by big data that should be solved.For example,how to achieve the encrypted data access control in cloud has been a hot research topic recently.Although many fine-grained access control schemes in cloud storage based on attribute-based encryption cryptosystem were proposed,big data will lead new problems to access control and bring about new challenges in security when the cloud serves the IoT.In other words,the existing schemes are not scalable and their properties of security are not comprehensive.Therefore,it is hard to design a robust and reliable cloud storage encryption access control system based on them.Both of the above issues on VANETs and cloud computing require further research and discussion.Firstly,according to the characteristics of VANETs,this thesis proposed a heterogeneous aggregate signcryption scheme based on multi-trapdoor hash functions(MHASCS)in theory.This thesis proved that MHASCS satisfies adaptive security in random oracle and compared performance with other similar schemes.It is the first time that multi-trapdoor hash functions are applied to VANETs,and the aggregate verification algorithm is improved so that the verification stage is pairing-free and carries out constant scalar multiplications,which is different from the existing schemes.The performance analysis shows that the proposed scheme has the highest compuatational efficiency.Secondly,this thesis proposed a new secure communication protocol for VANETs based on MHASCS named MB VP,analyzed its security and compared the performance with oth-er similar protocols by programming.Our protocol guarantees the secure communication between vehicles and road side units.Specifically,our protocol guarantees integrity,con-fidentiality and non-repudiation of transmission data and authentication and anonymity of vehicles.In addition,the performance comparison shows that the efficiency of MB VP is the highest in the aggregate verification stage due to the excellent property of MHASCS.Finally,this thesis proposed an access control solution for encrypted data in cloud storage systems named COACS.This thesis proved the static security of COACS in random oracle,compared with other similar solution schemes and achieved a comprehensive simulation.Improved on the basis of large universe multi-authority ciphertext-policy attribute-based en-cryption schemes,COACS achieves privacy-preserving and verifiability while ensuring the same computational efficiency.Via an online/offline mechanism,COACS enables the mo-bile terminal with lower performance to serve as both a data uploader and a data user.Com-pared with the existing schemes,COACS is more comprehensive and scalable than others.Moreover,most of the data access control solutions based on attributed-based encryption schemes for cloud are still in the theoretical stage,which are distinguish from COACS in which a comprehensive simulation is made to evaluate the practical value more effectively.