Designing selective encryption (SE) schemes for H.265/HEVC has been attracted much attention with the advent of H.265/HEVC codec in the past two decades. However, the most SE algorithms for H.265/HEVC encrypt the syntax elements in the bypass mode to keep the bit rate. Moreover, the edge region of the video data is not sufficiently protected. To produce large visual distortion and edge loss, a tunable SE scheme for H.265/HEVC based on the chroma intra prediction mode (IPM) and coefficient scrambling is proposed. First, a pseudo-random number sequence is generated by AES-CTR. Then, the prediction, residual, and reconstruction information in the H.265/HEVC encoding process is encrypted by a pseudo-random sequence. It encrypts the syntax elements of context-based adaptive binary arithmetic coding (CABAC) in the bypass mode. Some syntax elements, including chroma IPM in the regular mode, are encrypted as well. To further protect the edge information, a coefficient scrambling is adopted. The edge information of each frame is extracted and the transform units (TUs) are classified according to it. Then, the coefficients of the TUs containing edge are scrambled. Finally, a sign used for marking the type of each TU is embedded into a coefficient. The experimental results and analysis show that the proposed scheme has better visual distortion and subjective evaluation results compared with some existing H.265/HEVC SE algorithms. Meanwhile, users can flexibly use the proposed SE scheme according to encryption performance and bit rate requirements, which is attractive in the scenario of protecting video in cloud servers.

A Tunable Selective Encryption Scheme for H.265/HEVC Based on Chroma IPM and Coefficient Scrambling

Advances in digital content transmission have increased in the past few years. Security of multimedia data is an imperative issue because of fast evolution of digital data exchanges over an unsecured network Multimedia data security is achieved by methods of cryptography, which deals with encryption of data Standard symmetric encryption algorithms provide better security for the multimedia data, but applying symmetric key encryption algorithm on more complex multimedia data, problem of computational overhead might be faced Over the last few years, several encryption algorithms have applied to secure video transmission. While a large number of multimedia encryption schemes have been proposed in the literature and some have been used in real time applications, cryptanalytic work has shown the existence of security problems and other weaknesses in most of the proposed multimedia encryption schemes. Encryption is a common technique to uphold multimedia security. MPEG video stream is quite different from traditional textual data because interframe dependencies exist in MPEG video. Special MPEG video encryption algorithms are required because of their special characteristics, such as coding structure, large amount of data and real-time constraints. Image and video encryption have applications in various fields including internet communication, multimedia systems, medical imaging, and military communication. The Advanced Encryption Standard (AES) algorithm is used and modified it, to reduce the calculation of the algorithm and for improving the encryption performance.

Modified AES based algorithm for MPEG video encryption

A selective video encryption method based on the manipulation of transform skip signal and sign bin is proposed for the HEVC standard. The basic performance of the proposed selective video encryption method is evaluated in terms of perceptual inspection, outline detection and sketch attack using various classes of test video sequences. Preliminary results show that the proposed method provides quality degradation up to −0.22 in SSIM score when compared to the conventional method [5]. In addition, the edge difference ratio is greater than 0.73, which is closed to the perfect dissimilarity with respect to the original video. Functional comparison between the proposed method and the conventional selective encryption methods is then presented.

HEVC selective encryption using transform skip signal and sign bin

In open network, it is important to keep sensitive information secure from becoming vulnerable to unauthorized access. Encryption is used to ensure high security for Images. Chaos has been widely used for image encryption for its different features. There are many chaos based encryption techniques. Most of the proposed discrete chaotic cryptographic approaches are based on stream or block cipher schemes. If these two schemes are combined the security level is improved. Novel image encryption is proposed based on combination of pixel shuffling. Chaos is used for expand diffusion & confusion in image. Chaotic maps gives advantages of large key space and high level security. We survey exiting work which uses different techniques for image encryption and analyse them with respect to various parameters. To evaluate security & performance, key space analysis, correlation coefficient, histogram, information entropy, NPCR, UACI etc. will be studied.

Image encryption using chaos theory

Digital images have become part of everyday life by demonstrating its usability in a variety of fields from education to space research. Confidentiality and security of digital images have grown significantly with increasing trend of information interchange over the public channel. Cryptography can be used as a successful technique to prevent image data from unauthorized access. Keeping the nature of image data in mind, several encryption techniques are presented specifically for digital images, in literature during past few years. These cryptographic algorithms lack a benchmark for evaluation of their performance, cryptographic security and quality analysis of recovered images. In this study, we have designed and developed a benchmark based on all the parameters necessary for a good image encryption scheme. Extensive studies have been made to categories all the parameters used by different researchers to evaluate their algorithms and an optimum benchmark for evaluation is formulated. This benchmark is used to evaluate three image encryption schemes. The results of evaluation have highlighted the specific application areas for these image encryption schemes.

http://www.mecs-press.org/ijcnis/ijcnis-v8-n12/IJCNIS-V8-N12-3.pdf

A Benchmark for Performance Evaluation and Security Assessment of Image Encryption Schemes

Multimedia data security is becoming important with the continuous increase of digital communications on internet. The encryption algorithms developed to secure text data are not suitable for multimedia application because of the large data size and real time constraint. In this paper, classification and description of various video encryption algorithms are presented. Analysis and Comparison of these algorithms with respect to various parameters like visual degradation, encryption ratio, speed, compression friendliness, format compliance and cryptographic security is presented.

/pdf/video-encryption-a-survey-4s87zeyvv0.pdf

Video Encryption: A Survey

Image applications have been increasing in recent years. Encryption is used to provide the security needed for image applications. In this paper, we classify various image encryption schemes and analyze them with respect to various parameters like tunability, visual degradation, compression friendliness, format compliance, encryption ratio, speed, and cryptographic security.

/pdf/performance-study-on-image-encryption-schemes-21uf1fitb9.pdf

Jolly Shah

Papers

Video Encryption: A Survey

Performance Study on Image Encryption Schemes