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In this paper we propose a real-time selective video encryption solution in the scalable extension of High Efficiency Video Coding (HEVC) standard, referred to as SHVC. The proposed scheme encrypts a set of sensitive SHVC parameters with a minimum delay and complexity overheads. The encryption process is performed at the CABAC binstring level and fulfils both constant bitrate and format compliant video encryption requirements. In addition, it preserves all SHVC functionalities, including bitstream extraction for mid-network adaptation and error resilience. We compare the performance of three selective SHVC encryption schemes: the first scheme encrypts only the lowest SHVC layer, the second encrypts all layers and the last scheme encrypts only the highest layer. The performance of the proposed schemes is assessed over different video encryption criteria, at different scalability configurations and various High Definition (HD) video sequences. Experimental results showed that encrypt only the lowest layer or all layers enables a high security level, while encrypting only the highest layer leads to a perceptual encryption solution, by slightly decreasing the highest layer quality. Moreover, the processing complexity of the proposed solution is assessed in the context of a real-time SHVC decoder. The complexity overhead remains low and does not exceed 6% of the real-time decoding of SHVC video sequences.

In this paper, we propose, implement, and analyze the structures of two keyed hashfunctions using the Chaotic Neural Network (CNN). These structures are based on Spongeconstruction, and they produce two variants of hash value lengths, i.e., 256 and 512 bits. The firststructure is composed of two-layered CNN, while the second one is formed by one-layered CNN anda combination of nonlinear functions. Indeed, the proposed structures employ two strong nonlinearsystems, precisely a chaotic system and a neural network system. In addition, the proposed study isa new methodology of combining chaotic neural networks and Sponge construction that is provedsecure against known attacks. The performance of the two proposed structures is analyzed in termsof security and speed. For the security measures, the number of hits of the two proposed structuresdoesn’t exceed 2 for 256-bit hash values and does not exceed 3 for 512-bit hash values. In terms ofspeed, the average number of cycles to hash one data byte (NCpB) is equal to 50.30 for Structure 1,and 21.21 and 24.56 for Structure 2 with 8 and 24 rounds, respectively. In addition, the performance ofthe two proposed structures is compared with that of the standard hash functions SHA-3, SHA-2, andwith other classical chaos-based hash functions in the literature. The results of cryptanalytic analysisand the statistical tests highlight the robustness of the proposed keyed hash functions. It also showsthe suitability of the proposed hash functions for the application such as Message Authentication,Data Integrity, Digital Signature, and Authenticated Encryption with Associated Data.

Nonlinear dynamic cryptosystems or chaos-based cryptosystems have been attracting a large amount of research since 1990. The critical aspect of cryptography is to face the growth of communication and to achieve the design of fast and secure cryptosystems. In this paper, we introduce three versions of a chaos-based cryptosystem based on a similar structure of the Zhang and Fridrich cryptosystems. Each version is composed of two layers: a confusion layer and a diffusion layer. The confusion layer is achieved by using a modified 2-D cat map to overcome the fixed-point problem and some other weaknesses, and also to increase the dynamic key space. The 32-bit logistic map is used as a diffusion layer for the first version, which is more robust than using it in 8-bit. In the other versions, the logistic map is replaced by a modified Finite Skew Tent Map (FSTM) for three reasons: to increase the nonlinearity properties of the diffusion layer, to overcome the fixed-point problem, and to increase the dynamic key space. Finally, all versions of the proposed cryptosystem are more resistant against known attacks and faster than Zhang cryptosystems. Moreover, the dynamic key space is much larger than the one used in Zhang cryptosystems. Performance and security analysis prove that the proposed cryptosystems are suitable for securing real-time applications.