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Constructions And Analyses Of Efficient Symmetric-Key Primitives For Authentication And Encryption., Sebati Ghosh Dr. Aug 2022

Constructions And Analyses Of Efficient Symmetric-Key Primitives For Authentication And Encryption., Sebati Ghosh Dr.

Doctoral Theses

In symmetric key cryptography there are two fundamental objectives, viz. 1. confidentiality or secrecy of message from unexpected party and 2. authentication of message which includes authenticating the source of the message as well as integrity of the message against any unwanted modification. Let us first concentrate on confidentiality. In classical symmetric key cryptography two parties, say Alice and Bob, first secretly exchange a key-pair (e, d). Later, if Alice wishes to send a secret message m ∈ M to Bob, she computes c = Ee(m) and transmits c to Bob. Upon receiving c, Bob computes Dd(c) = m and …


Computing Well-Structured Subgraphs In Geometric Intersection Graphs., Satyabrata Jana Dr. Jul 2022

Computing Well-Structured Subgraphs In Geometric Intersection Graphs., Satyabrata Jana Dr.

Doctoral Theses

For a set of geometric objects, the associative geometric intersection graph is the graph with a vertex for each object and an edge between two vertices if and only if the corresponding objects intersect. Geometric intersection graphs are very important due to their theoretical properties and applicability. Based on the different geometric objects, several types of geometric intersection graphs are defined. Given a graph G, an induced (either vertex or edge) subgraph H ⊆ G is said to be an well-structured subgraph if H satisfies certain properties among the vertices in H. This thesis studies some well-structured subgraphs finding problems …


Efficient Handover Mechanisms For Heterogeneous Networks., Shankar Kumar Ghosh Dr. Apr 2022

Efficient Handover Mechanisms For Heterogeneous Networks., Shankar Kumar Ghosh Dr.

Doctoral Theses

In this thesis, some analytical frameworks have been developed to analyze the effect of different system parameters on handover performances in heterogeneous network (HetNet) and based on such frameworks, some efficient handover algorithms have been proposed. The study starts with an analytical framework to investigate the effect of resource allocation mechanisms, upper layer mobility management protocols (MMPs) and handover decision metrics on user perceived throughput. This analysis reveals that among other factors, handover decision metric plays a crucial role in determining user perceived throughput in HetNet. Subsequently, we develop two handover decision metrics for ultra dense networks (UDN) and unlicensed …


Zero-Knowledge Proof, Deniability And Their Applications In Blockchain, E-Voting And Deniable Secret Handshake Protocols., Somnath Panja Dr. Feb 2022

Zero-Knowledge Proof, Deniability And Their Applications In Blockchain, E-Voting And Deniable Secret Handshake Protocols., Somnath Panja Dr.

Doctoral Theses

In this thesis, we propose a cryptographic technique for an authenticated, end-to-end verifiable and secret ballot election. Currently, almost all verifiable e-voting systems require trusted authorities to perform the tallying process except for the DRE-i and DRE-ip systems. We have shown a weaknesses in the DRE-ip system and proposed a solution. We have modified the DRE-ip system so that no adversary can create and post a valid ballot on the public bulletin board without detection. We provide security proofs to prove the security properties of the proposed scheme. We propose two methods to store these ballots using blockchain and cloud …


On Class Imbalanced Learning:Design Of Non-Parametricclassifiers, Performance Indices, And Deep Oversampling Strategies., Sankha Mullick Dr. Jan 2022

On Class Imbalanced Learning:Design Of Non-Parametricclassifiers, Performance Indices, And Deep Oversampling Strategies., Sankha Mullick Dr.

Doctoral Theses

The relevance of classification is almost endless in the everyday application of machine learning. However, the performance of a classifier is only limited to the fulfillment of the inherent assumptions it makes about the training examples. For example, to facilitate unbiased learning a classifier is expected to be trained with an equal number of labeled data instances from all of the classes. However, in a large number of practical applications such as anomaly detection, semantic segmentation, disease prediction, etc. it may not be possible to gather an equal number of diverse training points for all the classes. This results in …


Secret Sharing And Its Variants, Matroids,Combinatorics., Shion Samadder Chaudhury Dr. Dec 2021

Secret Sharing And Its Variants, Matroids,Combinatorics., Shion Samadder Chaudhury Dr.

Doctoral Theses

The main focus of this thesis is secret sharing. Secret Sharing is a very basic and fundamental cryptographic primitive. It is a method to share a secret by a dealer among different parties in such a way that only certain predetermined subsets of parties can together reconstruct the secret while some of the remaining subsets of parties can have no information about the secret. Secret sharing was introduced independently by Shamir [139] and Blakely [20]. What they introduced is called a threshold secret sharing scheme. In such a secret sharing scheme the subsets of parties that can reconstruct a secret …


Dealing With Classification Irregularities In Real-World Scenarios., Payel Sadhukhan Dr. Jul 2021

Dealing With Classification Irregularities In Real-World Scenarios., Payel Sadhukhan Dr.

Doctoral Theses

Data processing by the human sensory system comes naturally. This processing, commonly denoted as pattern recognition and analysis are carried out spontaneously by humans. In day to day life, in most cases, decision making by humans come without any conscious effort. From the middle of the past century, humans have shown interest to render their abstraction capabilities (pattern recognition and analysis) to the machine. The abstraction capability of the machine is ’machine intelligence’ or ’machine learning’ [87].The primary goal of machine learning methods is to extract some meaningful information from the ’data’. Data refers to the information or attributes that …


Studies On Diagnostic Coverage And X-Sensitivity In Logic Circuits., Manjari Pradhan Dr. Apr 2021

Studies On Diagnostic Coverage And X-Sensitivity In Logic Circuits., Manjari Pradhan Dr.

Doctoral Theses

Today’s integrated circuits comprise billions of interconnected transistors assembled on a tiny silicon chip, and testing them to ensure functional and timing correctness continues to be a major challenge to designers and test engineers with further downscaling of transistors. Although substantial progress has been witnessed during the last five decades in the area of algorithmic test generation and fault diagnosis, applications of combinatorial and machinelearning (ML) techniques to solve these problems remain largely unexplored till date. In this thesis, we study three problems in the context of digital logic test and diagnosis. The first problem is that of fault diagnosis …


Essays In Social Choice Theory., Dipjyoti Majumdar Dr. Feb 2021

Essays In Social Choice Theory., Dipjyoti Majumdar Dr.

Doctoral Theses

The purpose of this thesis is to explore some issues in social choice theory and decision theory. Social choice theory provides the theoretical foundations for the field of public choice and welfare economics. It tries to bring together normative aspects like perspective value judgements and positive aspects, like strategic con- siderations. The second feature which is our focus, is closely related to the problem of providing appropriate incentives to agents, an issue of prime importance in eco- nomics.Consider for example, a set of agents who must elect one among a set of can- didates. These candidates may be physical agents …


In Silicoidentification Of Toxins And Their Effect Onhost Pathways: Feature Extraction, Classificationand Pathway Prediction., Rishika Sen Dr. Jan 2021

In Silicoidentification Of Toxins And Their Effect Onhost Pathways: Feature Extraction, Classificationand Pathway Prediction., Rishika Sen Dr.

Doctoral Theses

Identification of toxins, which are either proteins or small molecules, from pathogens is of paramount importance due to their crucial role as first-line invaders infiltrating a host, often leading to infection of the host. These toxins can affect specific proteins, like enzymes that catalyze metabolic pathways, affect metabolites that form the basis of metabolic reactions, and prevent the progression of those pathways, or more generally they may affect the regular functioning of other proteins in signaling pathways in the host. In this regard, the thesis addresses the problem of identification of toxins, and the effect of perturbations by toxins on …


Provable Security Of Symmetric-Key Cryptographic Schemes., Ashwin Jha Dr. Oct 2020

Provable Security Of Symmetric-Key Cryptographic Schemes., Ashwin Jha Dr.

Doctoral Theses

In this thesis, we provide quantitative and/or qualitative improvements in the provable security of several symmetric-key schemes, encompassing major information security goals, viz. data authentication, encryption, and authenticated encryption.AUTHENTICATION AND INTEGRITY: Among authentication schemes, we analyze the CBC-MAC family and counter-based MACs (XMACC, XMACR, PCS, LightMAC etc.), referred as the XMAC family. First, we revisit the security proofs for CBC-MAC and EMAC, and identify a critical flaw in the state-of-the-art results. We revise the security proofs and obtain significantly better bounds in case of EMAC, ECBC and FCBC. Second, we study the security of CBC-MAC family, when the underlying primitive …


Mechanism Design In Sequencing Problems., Parikshit De Dr. Jul 2017

Mechanism Design In Sequencing Problems., Parikshit De Dr.

Doctoral Theses

Collective decision making is an important social issue, since it depends on individual preferences that are not publicly observable. Therefore, the question is, whether it is possible to elicit the private information available to individuals and then how to extract the private information in various strategic environment; Mechanism design deals with these questions. The difference between game theory and mechanism design is that, the former tries to predict the outcome of a strategic environment in some “equilibrium” but the latter tries to design or restrict the environment in such a way that the desired objective is attained, that is, the …


Some Contemporary Issues In Software Reliability., Vignesh Subrahmaniam Dr. Oct 2016

Some Contemporary Issues In Software Reliability., Vignesh Subrahmaniam Dr.

Doctoral Theses

No abstract provided.


Digital Circles And Balls: Characterization, Properties, And Applications To Image Analysis., Sahadev Bera Dr. Feb 2016

Digital Circles And Balls: Characterization, Properties, And Applications To Image Analysis., Sahadev Bera Dr.

Doctoral Theses

In this thesis, we have reported some new theoretical findings, empirical formulations, useful heuristics, and efficient algorithms related to digital circle, digital disc, and digital sphere, along with their practical applications to the analysis of geometric information embedded in a digital image. Detecting digital circles and circular arcs from a digital image is very important in shape recognition. Several image processing techniques were proposed over the years to extract circles and circular arc from a digital image and to interpret related issues. We have proposed a novel technique for the segmentation of a digital circle, which is based on a …


Some Results On Analysis And Implementation Of Hc-128 Stream Cipher., Shashwat Raizada Dr. Jan 2016

Some Results On Analysis And Implementation Of Hc-128 Stream Cipher., Shashwat Raizada Dr.

Doctoral Theses

The HC-128 stream cipher is a successful entrant in the eStream candidate list (software profile) and is the lighter variant of HC-256 stream cipher. Apart from the analysis by the designer of the cipher (Hongjun Wu) to conjecture the security of this cipher, there are only a few other observations on this cipher despite being the focus of researchers during the three phases of eStream evaluation and later efforts in the community. Till date none of the security claims in favor of HC-128 by the designer could be broken. One may expect HC-128 stream cipher to be popular in commercial …


On The Analysis Of Some Recursive Equations In Probability., Arunangshu Biswas Dr. Sep 2015

On The Analysis Of Some Recursive Equations In Probability., Arunangshu Biswas Dr.

Doctoral Theses

This thesis deals with recursive systems used in theoretical and applied probability. Recursive systems are stochastic processes {Xn}n≥1 where the Xn depends on the earlier Xn−1 and also on some increment process which is uncorrelated with the process Xn. The simplest example of a recursive system is the Random Walk, whose properties have been extensively studied. Mathematically a recursive system takes the form Xn = f(Xn−1, n), is the increment/ innovation procedure and f(·, ·) is a function on the product space of xn and n. We first consider a recursive system called Self-Normalized sums (SNS) corresponding to a sequence …


On Supervised And Unsupervised Methodologies For Mining Of Text Data., Tanmay Basu Dr. Jul 2015

On Supervised And Unsupervised Methodologies For Mining Of Text Data., Tanmay Basu Dr.

Doctoral Theses

The supervised and unsupervised methodologies of text mining using the plain text data of English language have been discussed. Some new supervised and unsupervised methodologies have been developed for effective mining of the text data after successfully overcoming some limitations of the existing techniques.The problems of unsupervised techniques of text mining, i.e., document clustering methods are addressed. A new similarity measure between documents has been designed to improve the accuracy of measuring the content similarity between documents. Further, a hierarchical document clustering technique is designed using this similarity measure. The main significance of the clustering algorithm is that the number …


Generic Constructions Of Different Cryptographic Primitives Over Various Public Key Paradigms., Sumit Kumar Pandey Dr. Feb 2015

Generic Constructions Of Different Cryptographic Primitives Over Various Public Key Paradigms., Sumit Kumar Pandey Dr.

Doctoral Theses

In this thesis, we study the generic construction of some cryptographic primitives over various public key paradigms like traditional Public Key Cryptosystems and Identity Based Cryptosystems. It can be broadly divided into two categories1. Generic construction of some highly secure cryptographic primitives from less secure cryptographic primitives, and2. Generic construction of some complex cryptographic primitives from basic cryptographic primitives. Mathematical tools provide a way to achieve cryptographic functionality like confidentiality, authentication, data-integrity, non-repudiation etc., but in the case of complex cryptographic functionality like achieving confidentiality and authentication at the same time or confidentiality, authentication and non-repudiation at the same time …


Coverage And Detection In Wireless Sensor Networks., Mrinal Nandi Dr. Feb 2014

Coverage And Detection In Wireless Sensor Networks., Mrinal Nandi Dr.

Doctoral Theses

A Wireless Sensor Networks (WSNs), which are two or three dimensional systems, usually consist of a large number of small sensors equipped with some processing circuit, and a wireless transceiver. The sensors have small size, low battery capacity, non-renewable power supply, small processing power, limited buffer capacity and low-power radio. They may measure distance, direction, speed, humidity, wind speed, soil makeup, temperature, chemicals, light, and various other parameters. The sensors are autonomous devices with integrated sensing, processing, and communication capabilities.In this thesis, we consider ‘coverage problem’ and ‘detection problem’ in Wireless Sensor Networks (WSNs) in grid as well as in …


Enhancing Effective Depth-Of-Field By Multi-Focus Image Fusion Using Morphological Techniques., Ishita De Ghosh Dr. Nov 2012

Enhancing Effective Depth-Of-Field By Multi-Focus Image Fusion Using Morphological Techniques., Ishita De Ghosh Dr.

Doctoral Theses

A scene to be photographed, usually includes objects at varying distances from the camera. Depth-of-field of a digital camera is the range of distance, all objects within which appear to be sharp in the image. Due to the low depth-of-field of the camera, images acquired by them often suffer from degradation called out-of-foc us blur. One way to enhance the effective depth-of-field is to acquire se veral images of a scene with focus on different parts of it and then combine these images into a single image in such a way that all regions of the scene are in focus. …


Blackbox Reduction Of Some Cryptographic Constructions., Rishiraj Bhattacharyya Dr. Oct 2012

Blackbox Reduction Of Some Cryptographic Constructions., Rishiraj Bhattacharyya Dr.

Doctoral Theses

No abstract provided.


Some Results On Cryptanalysis Of Rsa And Factorization., Santanu Sarkar Dr. Feb 2012

Some Results On Cryptanalysis Of Rsa And Factorization., Santanu Sarkar Dr.

Doctoral Theses

In this thesis, we propose some new results in Cryptanalysis of RSA and related Factorization problems. Till date, the best known algorithm to solve the Integer Factorization problem is the Number Field Sieve, which has a runtime greater than exp(log1/3 N) for factoring an integer N. However, if one obtains certain information about the RSA parameters, there are algorithms which can factor the RSA modulus N = pq quite efficiently. The intention of this thesis is to identify such weaknesses of the RSA cryptosystem and its variants. Further we study results related to factorization.In Africacrypt 2008, Nitaj presented a class …


Distributed Algorithms For Initialization And Topology Control In Wireless Ad Hoc Networks., Subhasis Bhattacharjee Dr. Jul 2011

Distributed Algorithms For Initialization And Topology Control In Wireless Ad Hoc Networks., Subhasis Bhattacharjee Dr.

Doctoral Theses

Wireless ad hoc networking is an upcoming communication technology that makes exchange of information possible without any pre-existing infrastructure. Over the last decade it has grabbed tremendous interest in the research community due to its easy deployability and high flexibility, with numerous applications to social, industrial and personal uses. In this thesis, we designed effcient light weight distributed algorithms based on minimal local information to resolve the problems related to the initialization and topology configuration of wireless ad hoc networks with special emphasis on optimal utilization of limited resources. Once the ad hoc nodes with in-built radio transceivers are deployed …


Studies On Public Key And Identity-Based Cryptographic Primitives., Mahabir Prasad Jhanwar Dr. Feb 2011

Studies On Public Key And Identity-Based Cryptographic Primitives., Mahabir Prasad Jhanwar Dr.

Doctoral Theses

No abstract provided.


Fast Placement And Floorplanning Methods In Modern Reconfigurable Fpgas., Pritha Baneerjee Dr. Jun 2010

Fast Placement And Floorplanning Methods In Modern Reconfigurable Fpgas., Pritha Baneerjee Dr.

Doctoral Theses

FPGA Field-programmable gate-arrays (FPGA) are programmable hardware platforms with pre-fabricated logic and interconnects, which are electrically programmed by the user to realize a variety of circuits frequently required in a wide range of applications. Unlike application-specific integrated-circuits (ASICs), where realization of a circuit design takes several man-hours and enormous effort, the pre-fabricated logic and interconnects can be quickly programmed according to the design specification and made functional. Thus, in contrast to the ASICs, FPGAs can be customized and reconfigured depending on the need of the user. A basic FPGA chip consists of a set of configurable logic blocks (CLB) and …


Application Of Combinatorial Structures To Key Predistribution In Sensor Networks And Traitor Tracing., Sushmita Ruj Dr. Feb 2010

Application Of Combinatorial Structures To Key Predistribution In Sensor Networks And Traitor Tracing., Sushmita Ruj Dr.

Doctoral Theses

From time immemorial people have used cryptography for secure communication. Cryptography has decided the fate of many kings and queens as well as the outcome of various wars. It has become all the more important nowadays, with the growing need of electronic communication. We now live in a society where electronic networks pervade all aspects of our professional and private lives. We all use cryptography when we do bank transfers by ATM, or SWIFT, while using the mobile phones and i-phones, SSL protocols or using password protected machines. Though electronic communication is fast and easy, it is vulnerable to security …


Geometric Characterization Of Digital Objects: Algorithms And Applications To Image Analysis., Arindam Biswas Dr. Sep 2009

Geometric Characterization Of Digital Objects: Algorithms And Applications To Image Analysis., Arindam Biswas Dr.

Doctoral Theses

Several problems of characterizing a digital object, and particularly, those related to boundary description, have been studied in this thesis. New algorithms and their applications to various aspects of image analysis and retrieval have been reported. A combinatorial technique for constructing the outer and inner isothetic covers of a digital object has been developed. The resolution of the background 2D grid can be changed by varying the grid spacing, and this procedure can be used to extract shape and topological information about the object. Next, an algorithm has been designed for constructing the orthogonal (convex) hull of a digital object …


Normal Surfaces And Heegaard Splittings Of 3-Manifolds., Tejas Kalelkar Dr. Aug 2009

Normal Surfaces And Heegaard Splittings Of 3-Manifolds., Tejas Kalelkar Dr.

Doctoral Theses

This thesis deals with various questions regarding normal surfaces and Heegaard splittings of 3-manifolds.Chapter 1The first chapter is divided into two parts. In the first, we give an outline of normal surface theory and mention some of its important applications. The second part gives an overview of the theory of Heegaard splitting surfaces and a few of its applications. None of the material covered in this chapter is original and it is meant solely as an exposition of known results.Chapter 2In this chapter, we give a lower bound on the Euler characteristic of a normal surface, a topological invariant, in …


Studies On Construction And List Decoding Of Codes On Some Towers Of Function Fields., M. Prem Laxman Das Dr. Mar 2009

Studies On Construction And List Decoding Of Codes On Some Towers Of Function Fields., M. Prem Laxman Das Dr.

Doctoral Theses

In everyday life, there arise many situations where two parties, sender and receiver, need to communicate. The channel through which they communicate is assumed to be binary symmetric, that is, it changes 0 to 1 and vice versa with equal probability. At the receiver’s end, the sent message has to be recovered from the corrupted received word using some reasonable mechanism. This real life problem has attracted a lot of research in the past few decades. A solution to this problem is obtained by adding redundancy in a systematic manner to the message to construct a codeword. The collection of …


Image And Video Compression Using Block Truncation Coding And Pattern Fitting For Fast Decoding., Bibhas Chandra Dhara Dr. Feb 2009

Image And Video Compression Using Block Truncation Coding And Pattern Fitting For Fast Decoding., Bibhas Chandra Dhara Dr.

Doctoral Theses

In the present era of multimedia, the requirement of image/video storage and transmission for video conferencing, image and video retrieval, video playback, etc. are increasing exponentially. As a result, the need for better compression technology is always in demand. The limited bandwidth of internet also asks for transmission of desired objects only. Progressive image transmission provides such facilities, where transmission is done in steps and the transmission of undesired image can be stopped at an early stage. Modern applications, in addition to high compression ratio, also demand for efficient encoding and decoding processes, so that computational constraint of many real-time …