Study And Implementation Of MPEG Encryption Technology

With the rapid developing of Internet and digital techniques, digital multimedia works are used widely and deeply, such as video on demand, paying TV program, video conferences and so on. All of these applications are in demand of different degree to the security of multimedia data. Therefore, the multimedia data encryption technology, as an important means for multimedia data protection, has been researched and applied widely. The distinction between the multimedia applications and the ordinary computer applications is the vast amount of data generated by multimedia applications and the real-time constraints required by the multimedia applications. Traditional cryptographic algorithms for data encryption such as DES are not fast enough to process the vast amount of data generated by the multimedia applications, therefore new algorithms should by studied.Several videos encryptions rely on methods of directly distorting the visual image data (in the spatial domain) such that, without de-scrambling, the video appears unintelligible to a viewer, but in general the scrambling techniques will significantly change the statistical property of the original video, thus make it very difficult to compress. Another potential drawback of scrambling video in the spatial domain that the highly spatially and temporally correlated nature of the video data can be used for efficient attacks.To achieve real time encryption and video data transcoding, current MPEG video encryption methods usually integrate encryption algorithm with MPEG video compression course. The encryption algorithm includes selective algorithm, DCT coefficient permutation algorithm, and motion vector encryption and so on. Each of these algorithms has its advantage and disadvantage. This article is devoted to discussing the video encryption technology, by encrypting to avoid unauthorized person getting video data. This paper surrounds video encryption techniques and having done the following work:(1) Introducing the normal frame of MPEG encryption. Analyzing, testing andevaluating some encryption schemes which have been proposed.(2) Studying the position where encryption algorithm can be exerted and its effect.(3) Presenting a tradeoff encryption scheme based on the characteristic of MPEG compression. The framework can use different algorithm to achieve different security demand. It provides three levels of security, has very limited adverse impact on the compression, and allows more flexible selective encryption, transcodability, transparency and some other useful features. The experimental results show that the scheme can satisfactory results.