Summary With the rapid development of technology, digital multimedia has been widely utilized. Access of multimedia contents has become a daily routine. Although multimedia brings ease and convenience for content sharing, it also makes piracy more feasible. For example, it is easy to upload a copyrighted video to YouTube without the owners' permission. Authors and merchants are very much in need of protecting their intellectual property and commercial profits. Digital right management (DRM) systems are provided to fulfill this desire. DRM is a collection of techniques used to control access to copyrighted materials. Because current enterprise DRM solutions are not allowed for customized modification, they cannot fit in our considered scenario perfectly. As a result, we propose a secure DRM system with a design based on user demands, where a consumer can access contents only on authenticated devices until the authorization expires. Our DRM scheme involves a series of robust cryptosystems including AES, SHA‐256, and RSA. Applications as DRM agents are implemented on Windows, Mac OS, Android, and iOS platforms. Moreover, we modularized the DRM components for easy extension and integration. For better performance on low‐end devices, parameters of encryption are introduced, namely, the key size and the encryption density. We addressed the mask shift problem caused by random access and implemented the device identifier acquirement. The DRM system also proved to have high security and good performance in our analysis. Copyright © 2017 John Wiley & Sons, Ltd.

Low operation voltage organic thin film transistors (OTFTs) were successfully fabricated with top contact structure at low fabrication temperature. The thin gate dielectric of OTFTs were deposited by atmospheric pressure plasma jet at the substrate temperature about 150and under atmospheric pressure. The environment of processes would significantly improve the abilities of large area application for display and decrease the cost of instruments. We found that the quality of silicon oxide deposited with atmospheric pressure plasma jet strongly depended on the main gas and the gap distance between the plasma nozzle and the surface of the device and even influenced the deposition rate. Due to the improvement of gate insulator quality, good electrical characteristics of OTFTs can be obtained, such as carrier mobility as large as 0.66 cm 2 / V s, operation voltage as low as -2 V, and subthreshold swing as low as 0.7 V/dec.

In this study, we have fabricated OTFTs using poly-3-hexylthiophene (P3HT) as an active layer and SiO2 as gate dielectric layer which was modified by the atmospheric-pressure plasma technology (APPT). Processes of APPT are below 120{degree sign}C and at atmospheric pressure. The effects of surface treatment of SiO2 on electric characteristics of OTFTs were investigated. After surface treatment, the field-effect transistor has a threshold voltage within -10V and a field-effect mobility of 0.02-0.03 cm2/Vs which was 15-fold improvement over the mobility on bare silicon oxide. This study suggests an interesting direction for preparation of high-performance OTFTs with high efficiency and low temperature of surface treatment process by APPT.