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The present research work introduces a novel VLSI design of Context-Based Adaptive Variable Length Coding (CAVLC) entropy encoder. The proposed design is intended to be used for H.264/AVC CAVLC entropy encoder. The architecture is designed to be used as a part of a comprehensive H.264 video coding system. This hardware works in parallel and pipelined fashion and demonstrates a fair trade-off between...
The HEVC standard is one of the newest video coding standards developed to face the upcoming challenges concerning video processing. HEVC allows only one type of entropy encoder, which is the CABAC (Context Adaptive Binary Arithmetic Coding), responsible for the symbolic data representation in order to translate the final video bitstream to a smaller number of bits. This work presents hardware architecture...
Encryption is often not sufficient to secure communication, since it does not hide that communication takes place or who is communicating with whom. Covert channels hide the very existence of communication enabling individuals to communicate secretly. Previous work proposed a covert channel hidden inside multi-player first person shooter online game traffic (FPSCC). FPSCC has a low bit rate, but it...
Encoding spatio-temporally varying textures is challenging for standardised video encoders, with significantly more bits required for textured blocks compared to non-textured blocks. It is therefore beneficial to understand video textures in terms of both their spatio-temporal characteristics and their encoding statistics in order to optimize coding modes and performance. To this end, we examine the...
The paper is focused on use of Pulse Coupled Neural Network (PCNN) in the image steganography based on the research in the field of invariant image recognition. In general, steganography deals with data concealing in the cover mediums which can be freely accessible or transmitted by various communication channels without any restriction. A suitable position of hidden message is crucial for a successful...
Ethio-Telecom, the sole telecom service provider in Ethiopia, is expanding its mobile network infrastructures to reach its target of over 100 million subscribers in the next few years. As a result of this expansion and with the introduction of new services a considerable amount of electronic information (eg. E-mail, Short Message Service (SMS), etc.) written in local languages is expected to be generated...
DNS tunnel is a typical Internet covert channel used by attackers or bots to evade the malicious activities detection. The stolen information is encoded and encapsulated into the DNS packets to transfer. Since DNS traffic is common, most of the firewalls directly allow it to pass and IDS does not trigger an alarm with it. The popular signature-based detection methods and threshold-based methods are...
This paper focuses on one type of Covert Storage Channel (CSC) that uses the 6-bit TCP flag header in TCP/IP network packets to transmit secret messages between accomplices. We use relative entropy to characterize the irregularity of network flows in comparison to normal traffic. A normal profile is created by the frequency distribution of TCP flags in regular traffic packets. In detection, the TCP...
We extend Kawamura and Cook's framework for computational complexity for operators in analysis. This model is based on second-order complexity theory for functionals on the Baire space, which is lifted to metric spaces via representations. Time is measured in the length of the input encodings and the output precision.
Jalali and Poor (“Universal compressed sensing,” arXiv:1406.7807v3, Jan. 2016) have recently proposed a generalization of Rényi's information dimension to stationary stochastic processes by defining the information dimension of the stochastic process as the information dimension of k samples divided by k in the limit as k →∞ to. This paper proposes an alternative definition of information dimension...
The problem of computing the modulo-sum of messages over a finite-field erasure multiple access channel (MAC) is studied, and the role of feedback for function computation is explored. Our main contribution is two-fold. First, a new outer bound on the non-feedback computation capacity is proved, which strictly improves the state of the art [1]. The new outer bound answers a previously unsettled question...
Data shaping is a coding technique that has been proposed to increase the lifetime of flash memory devices. Several data shaping codes have been described in recent work, including endurance codes [2] and direct shaping codes for structured data [8], [4], [5]. In this paper, we study information-theoretic properties of a general class of data shaping codes and prove a separation theorem stating that...
Given a sufficient statistic for a parametric family of distributions, one can estimate the parameter without access to the data itself. However, the memory or code size for storing the sufficient statistic may nonetheless still be prohibitive. Indeed, for n independent data samples drawn from a k-nomial distribution with d = k − 1 degrees of freedom, the length of the code scales as d log n + O(1)...
Motivated by applications of biometric identification and content identification systems, we consider the problem of random coding for channels, where each codeword undergoes vector quantization, and where the decoder bases its decision only on the compressed codewords and the channel output, which is in turn, the channel's response to the transmission of an original codeword, before compression....
We introduce the problem of variable-length source resolvability, where a given target probability distribution is approximated by encoding variable-length uniform random numbers, and the asymptotically minimum average length rate of the uniform random numbers, called the (variable-length) resolvability, is investigated. We first analyze the variable-length resolvability with the variational distance...
The downlink of symmetric Cloud Radio Access Networks (C-RANs) with multiple relays and a single receiver is studied. Lower and upper bounds are derived on the capacity. The lower bound is achieved by Marton's coding which facilitates dependence among the multiple-access channel inputs. The upper bound uses Ozarow's technique to augment the system with an auxiliary random variable. The bounds are...
The corner points of the capacity region of the two-user Gaussian interference channel under strong or weak interference are determined using the notions of almost Gaussian random vectors, almost lossless addition of random vectors, and almost linearly dependent random vectors. In particular, the “missing” corner point problem is solved in a manner that differs from previous works in that it avoids...
An ideal Physical Unclonable Function produces a string of static random bits. Noise causes these bits to be unstable over subsequent readings and biases cause these bits to have a tendency towards a fixed value. Although the debiasing of random strings is a well-studied problem, the combined problem of noise and bias is unique to PUF design. This paper proposes a new lightweight noise-aware debiasing...
We demonstrate a vulnerability in existing content-based message filtering methods, showing how an attacker can use a simple obfuscator to modify any message to a homograph version of the same message, thereby avoiding digest and signature based detection methods. We measure the success of this potential attack against Hotmail, Gmail and Yahoo mail. While the attack is bothersome both in terms of...
We present Marlin, a variable-to-fixed (VF) codec optimized for decoding speed. Marlin builds upon a novel way of constructing VF dictionaries that maximizes efficiency for a given dictionary size. On a lossless image coding experiment, Marlin achieves a compression ratio of 1.94 at 2494MiB/s. Marlin is as fast as state-of-the-art high-throughput codecs (e.g., Snappy, 1.24 at 2643MiB/s), and its compression...
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