Current Issue : April - June Volume : 2021 Issue Number : 2 Articles : 5 Articles
In botnets, a bot master regularly sends command and control messages (C & C messages) to bots for various purposes, such as ordering its commands to bots and collecting critical data from bots. Although such C & C messages can be encrypted by cryptographic methods to hide them, existing botnet detection mechanisms could detect the existence of botnets by capturing suspicious network traffics between the bot master (or the C & C server) and numerous bots. Recently, steganographybased botnets (stego-botnets) have emerged to make C & C communication traffics look normal to botnet detection systems. In stego-botnets, every C & C message is embedded in a multimedia file, such as an image file by using steganography techniques and shared in Social Network Service (SNS) websites (such as Facebook) or online messengers (such as WeChat or KakaoTalk). Consequently, traditional botnet detection systems without steganography detection methods cannot detect them. Meanwhile, according to our survey, we observed that existing studies on the steganography botnet are limited to use only image steganography techniques, although the video steganography method has some obvious advantages over the image steganography method. By this motivation, in this paper, we study a video steganography-based botnet in Social Network Service (SNS) platforms. We first propose a video steganography botnet model based on SNS messengers. In addition, we design a new payload approach-based video steganography method (DECM: Divide-Embed- Component Method) that can embed much more secret data than existing tools by using two open tools VirtualDub and Stegano. We show that our proposed model can be implemented in the Telegram SNS messenger and conduct extensive experiments by comparing our proposed model with DECM with an existing image steganography-based botnet in terms of C & C communication efficiency and undetectability....
An integrated simulation tool called Video Delivery Simulation Framework over Vehicular Networks (VDSF-VN) is presented. This framework is intended to allow users to conduct experiments related to video transmission in vehicular networks by means of simulation. Research on this topic requires the use of many independent tools, such as traffic and network simulators, intermediate frameworks, video encoders and decoders, converters, platform-dependent scripting languages, data visualisation packages and spreadsheets, and some other tasks are performed manually. The lack of tools necessary to carry out all these tasks in an integrated and efficient way formed the motivation for the development of the VDSF-VN framework. It is managed via two user-friendly applications, GatcomSUMO and GatcomVideo, which allow all the necessary tasks to be accomplished. The first is primarily used to build the network scenario and set up the traffic flows, whereas the second involves the delivery process of the whole video, encoding/decoding video, running simulations, and processing all the experimental results to automatically provide the requested figures, tables and reports. This multiplatform framework is intended to fill the existing gap in this field, and has been successfully used in several experimental tests of vehicular networks....
Video streaming application such as Youtube is one of the most popular mobile applications. To adjust the quality of video for available network bandwidth, a streaming server provides multiple representations of video of which bit rate has different bandwidth requirements. A streaming client utilizes an adaptive bit rate (ABR) scheme to select a proper representation that the network can support. However, in mobile environments, incorrect decisions of an ABR scheme often cause playback stalls that significantly degrade the quality of user experience, which can easily happen due to network dynamics. In this work, we propose a control theory (Linear Quadratic Optimization)- based ABR scheme to enhance the quality of experience in mobile video streaming. Our simulation study shows that our proposed ABR scheme successfully mitigates and shortens playback stalls while preserving the similar quality of streaming video compared to the state-of-the-art ABR schemes....
Computer simulation is a significant technology on making great scenes of crowd in the film industry. However, current animation making process of crowd motion requires large manual operations which are time-consuming and inconvenient. To solve the above problem, this paper presents an editing method on the basis of mesh deformation that can rapidly and intuitively edit crowd movement trajectories from the perspective of time and space. The method is applied to directly generate and adjust the crowd movement as well as avoid the crash between crowd and obstacles. As for collisions within the crowd that come along with path modification problem, a time-based solution is put forward to avoid this situation by retaining relative positions of individuals. Moreover, an experiment based on a real venue was performed and the result indicates that the proposed method can not only simplify the editing operations but also improve the efficiency of crowd motion editing....
In this paper, we propose an efficient cryptosystem for digital image encryption and authentication. The cryptosystem is a hybrid scheme that uses symmetric and asymmetric approaches. The first one is used to encrypt the host image by utilizing a chaos-based key generator. The second one is used to encrypt the initial secret key and the owner’s signature that permit authentication. The algorithm is evaluated and validated by its application on several types of standard images and tools such as the statistical analysis, the key, and the performance analysis. The results indicate that the proposed cryptosystem provides high performance and enhanced security. The NIST 800-22 is used for testing the pseudorandom numbers generation (PRNG). The obtained simulation results are better than those cited in the recent works in terms of execution time and security level and low computational complexity....
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