Pricing strategies for tied digital contents and devices

Media companies are increasingly offering digital content to consumers. Many of these companies are tying digital content with their proprietary digital devices. In this study, we develop a consumer demand model for digital device and digital content based on a constant elasticity demand function. In modeling consumer valuation of the digital device, we take consumer surplus on digital content into account. We further derive equilibrium prices for digital devices based on an oligopoly competition model with horizontal product differentiation. We analyze the equilibrium prices and how prices affect firm profits. We find product differentiation and the level of product substitutability affect prices. We also find that content price plays a significant role in affecting the price of the digital device. Content price can either increase or decrease the tied digital device price depending on the profit margin and demand elasticity of the digital content. We further analyze how content and device prices affect their respective profits and the overall profit of the firm. We extend our model to vertical product differentiation and find vertical product differentiation and the level of product quality affect prices.     

DRM中流媒体加密密钥切换技术研究与实现

针对数字版权管理（DRM）系统中流媒体的内容加密密钥不易更换的问题和基于OMA DRM2．0规范与ISO13818-1 MPEG 2 TS标准框架,提出提前下发期、密钥过渡期及切换时间窗的机制和严密的内容加密密钥切换时序流程,实现流媒体内容加密密钥平滑切换,提高DRM系统安全性,不影响用户正常收看流媒体节目。     

Redistributing time-based rights between consumer devices for content sharing in DRM system

Device-based digital rights management (DRM) systems tightly bind rights for content to a device. However, it can decrease the consumers’ convenience because it disturbs consumers who want to use the already purchased content with their other devices freely. Previous research into solving this problem still have burdens such as restricting the number of devices that a consumer can use and requiring a special device that manages content sharing. In this paper, we propose a new rights sharing scheme which does not restrict the number of devices that a consumer can use and does not require a specialized device. In our scheme, the right to use content is represented as the right to use the content for a certain amount of time. Consumers can use the content with any of their devices by redistributing the usage amount of time between devices. The redistribution process only requires local synchronization among participating devices. To prevent illegal content sharing and to detect illegally increased content usage time, the amount of time that a consumer can have is limited and the rights for each unit of time has a unique number to prevent illegal duplications. We present data structures and protocols, analyze security properties of our scheme, compare our scheme with related work, and evaluate our scheme through implementation.

Security enhancement for digital signature schemes with fault tolerance in RSA

Digital signature schemes with fault tolerance make it possible for error detections and corrections during the processes of data computations and transmissions. Recently, Zhang, in 1999, and Lee and Tsai, in 2003, have respectively proposed two efficient fault-tolerant schemes based on the RSA cryptosystem. Both of them can efficiently check the sender’s identity and keep the confidentiality of the transmitted document. Furthermore, they can detect the errors and correct them. However, these schemes have a common weakness in security, that is, different messages may easily be computed that have the same signature. Thus, a valid signature could be reused in another document. This severely violates the principles of digital signature. In this paper, we shall show that this security flaw existed in the two perviously proposed schemes and conclude that the security flaw may occur in other fault-tolerant public key cryptosystems that are similar to these schemes. Furthermore, we will improve Zhang’s and Lee and Tsai’s schemes to eliminate the drawbacks.     

ICT capabilities for supporting collaborative work on business processes within the digital content industry

The digital content industry requires the integration of specialized information and communications technology (ICT) capabilities to support collaborative work for planning and executing its business processes. In particular, this knowledge-intensive industry lacks for adequate control on product documentation, inter and intra organizational resources management, and process monitoring which is required for supporting the high demand of projects typically constrained in time, costs, and quality. This paper presents a defined maturity model named DigiCoMM to assess collaboration and interoperability capabilities that are specific to pre-production, production, and post-production processes within the digital content industry. It also presents MONO, a computer-supported collaborative work (CSCW) software for supporting the incremental transition of companies through the different levels of the maturity model. MONO was developed in the context of the DAVID research project (Strategic Programme for the Research and Development of the Colombian Animation and Video Games Industry), during the period of 2012–2015. This model and software were used to assess and support the collaborative capabilities of several animation and video game companies in Colombia.     

一种面向DRM的多媒体社交网络信任模型

在多媒体社交网络中,用户间的信任关系直接影响数字内容的分享与传播方式。为准确评估用户间的信任关系,引入数字内容可信反馈、反馈权衡因子、用户分享相似性等分享特性因子,基于小世界理论,建立一种面向数字版权管理的多媒体社交网络信任模型MSNTM。实验结果表明,MSNTM能够实时动态地更新用户间的信任值,准确度量信任关系,并识别分享虚拟社区中的恶意用户。