Real-Time Chaotic Video Encryption Based on Multithreaded Parallel Confusion and Diffusion

Table of Links

Abstract & Introduction

Strategy Description

Encryption Speed Evaluation

Statistical Evaluation

Security Analysis

Parameter Setup

Comparison To Previous Works

Conclusions

Acknowledgments & References

Abstract

Due to the strong correlation between adjacent pixels, most image encryption schemes perform multiple rounds of confusion and diffusion to protect the image against attacks. Such operations, however, are time-consuming, cannot meet the real-time requirements of video encryption. Existing works, therefore, realize video encryption by simplifying the encryption process or encrypting specific parts of video frames, which results in lower security compared to image encryption. To solve the problem, this paper proposes a real-time chaotic video encryption strategy based on multithreaded parallel confusion and diffusion. It takes a video as the input, splits the frame into subframes, creates a set of threads to simultaneously perform five rounds of confusion and diffusion operations on corresponding subframes, and efficiently outputs the encrypted frames. The encryption speed evaluation shows that our method significantly improves the confusion and diffusion speed, realizes real-time 480 × 480, 576 × 576, and 768 × 768 24FPS video encryption using Intel Core i5-1135G7, Intel Core i7-8700, and Intel Xeon Gold 6226R, respectively. The statistical and security analysis prove that the deployed cryptosystems have outstanding statistical properties, can resist attacks, channel noise, and data loss. Compared with previous works, to the best of our knowledge, the proposed strategy achieves the fastest encryption speed, and realizes the first real-time chaotic video encryption based on multi-round confusion-diffusion architecture, thus, providing a more secure and feasible solution for practical applications and related research.

Keywords: Real-time video encryption, Parallel computing, Chaotic systems, Confusion and diffusion

1. Introduction

With the rapid development of information and communication technologies, images and videos have shown enormous potential in data storage and network transmission, resulting in extensive application requirements for image and video encryption [1]. However, most conventional cryptographic schemes, such as DES, AES, RSA, etc., are designed to protect textual information, they are not suitable for images and videos [2]. As a result, many image encryption protocols have been proposed over recent years based on different techniques [3, 4, 5, 6], in which chaos based methods attract significant attention, due to the intrinsic characteristics of chaotic systems, including ergodicity, non-periodicity, non-convergence, sensitivity to initial conditions and control parameters, et al. [7]. Most chaos based image encryption algorithms comprises confusion and diffusion phases [8]. In the former phase, the pixel positions are scrambled over whole image without changing the values [9]. In the latter phase, the pixel values are modified sequentially with the byte sequences generated by chaotic systems [10].

Such confusion-diffusion architecture based image encryption protocols need to perform the two phases for multiple rounds until a satisfactory security level is achieved [11]. This, obviously, is very time-consuming and cannot meet the realtime requirements of video encryption. Existing works, therefore, realize video encryption through simplifying encryption process or encrypting specific pixels in the video[12, 13]. For the first category (also known as the full encryption), for example, Ref. [14] selects three chaotic maps to generate byte sequences, and directly performs XOR operations between the pixels and the generated bytes to encrypt the video; Refs. [15] use the generated bytes to encrypt the frame, and take the encrypted pixels as feedback to improve the plaintext sensitivity of the deployed cryptosystem; Ref. [16] performs one round of confusion operation on the video frame, followed by acting XOR operations between the pixels and the generated bytes to realize frame encryption; Since practical applications put forward higher requirements for security, most recently published works are based on one-round confusion-diffusion architecture[17, 18, 19, 20, 21, 22]. The second category is also known as the selective encryption, the algorithms belong to this category encrypt specific pixels in the video frame to reduce the computational complexity [23]. These categories of strategies, clearly, achieve high efficiency at the expense of security.

Therefore, how to realize real-time video encryption without compromising the security has become an urgent problem to be solved. In the field of full video encryption, however, there are few related research. And to the best of our knowledge, existing works cannot realize real-time video encryption, i.e., the the number of frames encrypted in a second is larger than FPS (Frames Per Second) of the video or the average encryption time (ms) is less than 1000 / FPS. This paper, thus, takes the advantage of parallel computing, designs a five-round confusion-diffusion architecture based real-time chaotic video encryption strategy. To evaluate the performance, two cryptosystems are implemented using two different chaotic maps. Three hardware platforms are used to assess the encryption speed of the deployed cryptosystems. The evaluation results show that our strategy significantly improves the speed of byte generation, confusion, and diffusion, laying the foundation for the realization of real-time video encryption. The statistical and security analysis prove that the deployed cryptosystems have outstanding statistical properties and resistance to attacks, channel noise and data loss. The proposed strategy also suitable for many confusion and diffusion methods, and can be easily realized with both software and hardware.

The rest of the paper are organized as follows: section 2 gives a detailed description of the proposed strategy. In section 3, two typical chaotic maps are selected to realize the strategy, and the encryption speed of the deployed cryptosystems are evaluated using three different hardware platforms. Section 4 and 5 carry out statistical and security analysis, respectively. Section 6 analyzes the reasons for the parameter settings used in this paper. In section 7 gives a comparison to recent published works, followed by a brief conclusion in section 8.