An Anonymous Authentication Scheme with Controllable Linkability for Vehicle Sensor Networks

Vehicle sensor networks(VSN)play an increasingly important part in smart city,due to the interconnectivity of the infrastructure.However similar to other wireless communications,vehicle sensor networks are susceptible to a broad range of attacks.In addition to ensuring security for both data-at-rest and data-in-transit,it is essential to preserve the privacy of data and users in vehicle sensor networks.Many existing authentication schemes for vehicle sensor networks are generally not designed to also preserve the privacy between the user and service provider(e.g.,mining user data to provide personalized services without infringing on user privacy).Controllable linkability can be used to facilitate an involved entity with the right linking key to determine whether two messages were generated by the same sender,while preserving the anonymity of the signer.Such a functionality is very useful to provide personalized services.Thus,in this paper,a threshold authentication scheme with anonymity and controllable linkability for vehicle sensor networks is constructed,and its security is analyzed under the random oracle model.

Enhanced dechlorination of 2,4-dichlorophenol by recoverable Ni/Fe–Fe_3O_4 nanocomposites

Ni/Fe-Fe3O4 nanocomposites were synthesized for dechlorination of 2,4-dichlorophenol （2,4-DCP）. The effects of the Ni content in Ni/Fe-Fe3O4 nanocomposites, solution pH, and common dissolved ions on the dechlorination efficiency were investigated, in addition to the reusability of the nanocomposites. The results showed that increasing content of Ni in Ni/Fe-FesO4 nanocomposites, from 1 to 5 wt.%, greatly increased the dechlorination efficiency; the Ni/Fe-Fe3O4 nanocomposites had much higher dechlorination efficiency than bare Ni/Fe nanoparticles. Ni content of S wt.% and initial pH below 6.0 was found to be the optimal conditions for the catalytic dechlorination of 2,4-DCP. Both 2,4-DCP and the intermediate product 2-chlorophenol （2-CP） were completely removed, and the concentra- tion of the final product phenol was close to the theoretical phenol production from complete dechlorination of 20 mg/L of 2,4-DCP, after 3 hr reaction at initial pH value of 6.0, 3 g/L Ni/Fe-Fe3O4, S wt.% Ni content in the composite, and temperature of 22℃ 2,4-DCP dechlorination was enhanced by C1- and inhibited by NO3- and SO42-. The nanocomposites were easily separated from the solution by an applied magnetic field. When the catalyst was reused, the removal efficiency of 2,4-DCP was almost 100% for the first seven uses, and gradually decreased to 75% in cycles 8-10. Therefore, the Ni/Fe-Fe3O4 nanocomposites can be considered as a potentially effective tool for remediation of Pollution bv 2.4-DCP.