A generic partial encryption scheme for low-power mobile devices

Abstract

Content protection that allows only legitimate users to use specified content is essential in order to secure business in the consumer market. However, service providers and users suffer from low responsiveness when content is encrypted with traditional cryptographic tools that require strong decryption algorithms on mobile devices. In this paper, we introduce a generic partial encryption scheme for low-power mobile devices. Our primary goal is to design a generic architecture for partial encryption of downloadable and real-time streaming contents, and also to facilitate a trade-off between minimizing the encryption/decryption overhead and providing sufficient DRM security for the service provider. We also evaluate the efficacy of our proposed scheme by applying it to real-world multimedia contents. The results of our experiments indicate that encrypting only a small portion (about 2.5 %) of video content can effectively impose DRM restriction on the content. This significantly reduces the decryption overhead on low-power mobile devices. In the smart phone environment, it is shown that the time overhead during the decryption is less that 5 % of on-the-fly decoding time and the power overhead is reduced by up to 94.5 %, compared to the traditional full encryption scheme.