Initial Bits Research Articles

Quantum Random Access Codes for Boolean Functions

Ann↦pmrandom access code (RAC) is an encoding ofnbits intombits such that any initial bit can be recovered with probability at leastp, while in a quantum RAC (QRAC), thenbits are encoded intomqubits. Since its proposal, the idea of RACs was generalized in many different ways, e.g. allowing the use of shared entanglement (called entanglement-assisted random access code, or simply EARAC) or recovering multiple bits instead of one. In this paper we generalize the idea of RACs to recovering the value of a given Boolean functionfon any subset of fixed size of the initial bits, which we callf-random access codes. We study and give protocols forf-random access codes with classical (f-RAC) and quantum (f-QRAC) encoding, together with many different resources, e.g. private or shared randomness, shared entanglement (f-EARAC) and Popescu-Rohrlich boxes (f-PRRAC). The success probability of our protocols is characterized by thenoise stabilityof the Boolean functionf. Moreover, we give anupper boundon the success probability of anyf-QRAC with shared randomness that matches its success probability up to a multiplicative constant (andf-RACs by extension), meaning that quantum protocols can only achieve a limited advantage over their classical counterparts.

Analysis Of Database Record Compression Using The Levenstein Algorithm

Data stored in the database affects how much storage memory is used. The more data stored, the more memory will be used. To reduce memory usage it is necessary to reduce the data to be stored. The technique that can be used is data compression. Levenstein algorithm is a data compression technique that replaces the initial bits of the string, resulting in smaller compression. Levenstein algorithm is suitable for compressing data that has many repetitions.

Design of Robust, High-Entropy Strong PUFs via Weightless Neural Network

Physically unclonable functions (PUFs) have been explored as lightweight hardware primitives for the purpose of realizing robust security via strong authentication or secure key/ID generation. PUF harness manufacturing process variations for the purpose of generating binary keys or binary functions. An ideal strong PUF is a binary function that maps an m-bit input challenge to an uniquen-bit output response, making it attractive for authentication applications. Unfortunately, real strong PUF implementations suffer from reliability issues where the same challenge may produce different responses in the presence of noise. To overcome this problem, strong PUF leverages the availability of exponential number of challenge-response pairs (CRPs). A successful authentication event requires acquiring multiple CRPs and applying a threshold. In contrast, weak PUFs produce limited keys and are required to be highly reliable. Multiple techniques have been developed to achieve the necessary reliability. An additional prerequisite for strong PUFs is resilience against model-building attacks (cloning) by an adversary, who has observed a few CRPs, to prevent successful prediction of future CRPs. In this work, we first illustrate a strong PUF design that re-purposes a weightless neural network (WNN). Second, we showcase the robustness of WNN-based strong PUFs with respect to machine learning attacks, while providing desirable uniqueness and reliability metrics. Finally, we employ an initial entropy source of highly reliable weak PUF bits mapped to weightless neural networks (WNNs) for the purpose of creating a near-ideal strong PUF in terms of reliability. Our results show that it is possible to create highly reliable WNN–based strong PUFs with < 65 % ML accuracy by using as few as 32 initial reliable weak PUF bits.

$BitCoding$ : Network Traffic Classification Through Encoded Bit Level Signatures

With many network protocols using obfuscation techniques to hide their identity, robust methods of traffic classification are required. In traditional deep-packet-inspection (DPI) methods, application specific signatures are generated with byte-level data from payload. Increasingly new data formats are being used to encode the application protocols with bit-level information which render the byte-level signatures ineffective. In this paper, we describe BitCoding a bit-level DPI-based signature generation technique. BitCoding uses only a small number of initial bits from a flow and identify invariant bits as signature. Subsequently, these bit signatures are encoded and transformed into a newly defined state transition machine transition constrained counting automata. While short signatures are efficient for processing, this will increase the chances of collision and cross signature matching with increase in number of signatures (applications). We describe a method for signature similarity detection using a variant of Hamming distance and propose to increase the length of signatures for a subset of protocols to avoid overlaps. We perform extensive experiments with three different data sets consisting of 537 380 flows with a packet count of 3 445 969 and show that, BitCoding has very good detection performance across different types of protocols (text, binary, and proprietary) making it protocol-type agnostic. Further, to understand the portability of signatures generated we perform cross evaluation, i.e., signatures generated from one site are used for testing with data from other sites to conclude that it will lead to a small compromise in detection performance.

Simulation of BB84 and proposed protocol for quantum key distribution

Quantum key distribution is a secure way of transferring the keys among entities involved in communication. BB84 is the first protocol for QKD in year 1984. In this paper we are giving the simulation process of BB84 protocol in C++ and also the simulation of proposed protocol in C++ using object oriented approach. Proposed protocol uses a two-way quantum channel and also generates an additional initial bits sequence at another end for polarization.

Quantize-and-Forward Strategy for Interleave-Division Multiple-Access Relay Channel

The quantize-and-forward (QF) strategy for the half-duplex interleave-division multiple-access relay channel (ID-MARC) is investigated in this paper with multiple users, single relay, and single destination. Different from the orthogonal MARC, multiple users in such an ID-MARC are distinguished by different interleavers. For the case that the relay node cannot recover the initial bits correctly, a denoising mutual-information preserving quantizer (DMIPQ) is proposed, which can remove the noise from the received signal while preserving the useful information. A suboptimal searching algorithm is designed to reduce the complexity of DMIPQ. The approximation of DMIPQ is further discussed to get an analytical solution. It is shown that the approximate DMIPQ is equivalent to the minimum mean square error (MMSE) Lloyd-max quantizer. Numerical results illustrate that the proposed DMIPQ outperforms the MMSE Lloyd-max quantizer. It can be also shown that the bit error rate of the ID-MARC (BER) with DMIPQ is close to its compress-and-forward (CF) bounds.

Image Compression Using SPIHT with Modified Spatial Orientation Trees

A new way of reordering spatial orientation tree of SPIHT for improving compression efficiencies for monochrome and color images has been proposed. Reordering ensures that SPIHT algorithm codes more significant information in the initial bits. List of insignificant pixels and sets are initialized with fewer number of coefficients compared to conventional SPIHT for monochrome images. For color images an altered parent offspring relationship and an extra level of wavelet decomposition on chrominance planes were performed. PSNR improvement of 32.06% was achieved at 0.01 bpp for monochrome images and 19.76% for color images at 0.05 bpp compared to conventional schemes.

An efficient intra-frame rate control algorithm for H.264/AVC video coding

Intra-frame plays a significant role in improving video quality for rate control of H.264/AVC. In this paper, an efficient intra-frame rate control algorithm is proposed for H.264/AVC video coding. The proposed scheme adjusts the quantization parameter (QP) of intra-frame adaptively according to intra-frame buffer fullness ratio, current buffer fullness ratio, and skipped frame ratio. Experimental results demonstrate that for a set of typical testing sequences, the proposed scheme can obtain accurate target bit rate, better peak signal-to-noise ratio (PSNR) performance and reduce the number of skipped frames significantly, when compared with existing schemes. More importantly, the proposed scheme is very flexible for different initial QPs and target bits.

Linear Cryptanalysis of Simplified Trivium

Stream cipher Trivium is one of the seven finalists of the eSTREAM project.In this paper,we apply linear cryptanalysis to the simplified Trivium with the initialization of 288 rounds.The equation,which involves the key bits,initial vector bits and the first keystream bit in linear approximations for 288-round Trivium of Turan,is corrected.In addition,when special Key bits and IV bits are allowed to be chosen,the algorithm to search the linear approximations with the biggest linear bias is presented.Based on this algorithm,3 linear approximations with the same linear bias 2-25are found,which is better than Turan's 2-31.

An Efficient Algorithm for Software Generation of Binary Linear Recurrences

We describe a method for efficient software generation of binary linear sequences. Suppose that a machine sized word can hold an unsigned integer between 0 and 2w−1 and a binary linear sequence (s(t))t≥0 has a characteristic polynomial of degree n having l nonzero coefficients. Then given nw initial bits of the sequence, it is possible to generate successive blocks of (s(t))t≥0 of length w bits each. The time required to generate each block is equal to the time required to perform l bitwise XOR operations on machine sized words. Compared to the basic method of sequence generation, this provides a w-fold increase in speed.

Polynomial Factorization and Nonrandomness of Bits of Algebraic and Some Transcendental Numbers

We show that the binary expansions of algebraic numbers do not form secure pseudorandom sequences; given sufficiently many initial bits of an algebraic number, its minimal polynomial can be reconstructed, and therefore the further bits of the algebraic number can be computed. This also enables us to devise a simple algorithm to factor polynomials with rational coefficients. All algorithms work in polynomial time.

Polynomial factorization and nonrandomness of bits of algebraic and some transcendental numbers

We show that the binary expansions of algebraic numbers do not form secure pseudorandom sequences; given sufficiently many initial bits of an algebraic number, its minimal polynomial can be reconstructed, and therefore the further bits of the algebraic number can be computed. This also enables us to devise a simple algorithm to factor polynomials with rational coefficients. All algorithms work in polynomial time.