Dissertations / Theses on the topic 'Obfuscations'
To see the other types of publications on this topic, follow the link: Obfuscations.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Obfuscations.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Homoliak, Ivan. "Detekce Útoků v Síťovém Provozu." Doctoral thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2016. http://www.nusl.cz/ntk/nusl-261231.
Full textAbstract:
Tato práce se zabývá problematikou anomální detekce síťových útoků s využitím technik strojového učení. Nejdříve jsou prezentovány state-of-the-art datové kolekce určené pro ověření funkčnosti systémů detekce útoků a také práce, které používají statistickou analýzu a techniky strojového učení pro nalezení síťových útoků. V další části práce je prezentován návrh vlastní kolekce metrik nazývaných Advanced Security Network Metrics (ASNM), který je součástí konceptuálního automatického systému pro detekci průniků (AIPS). Dále jsou navrženy a diskutovány dva různé přístupy k obfuskaci - tunelování a modifikace síťových charakteristik - sloužících pro úpravu provádění útoků. Experimenty ukazují, že použité obfuskace jsou schopny předejít odhalení útoků pomocí klasifikátoru využívajícího metriky ASNM. Na druhé straně zahrnutí těchto obfuskací do trénovacího procesu klasifikátoru může zlepšit jeho detekční schopnosti. Práce také prezentuje alternativní pohled na obfuskační techniky modifikující síťové charakteristiky a demonstruje jejich použití jako aproximaci síťového normalizéru založenou na vhodných trénovacích datech.
2
Batchelder, Michael Robert. "Java bytecode obfuscation." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=18300.
Full textAbstract:
Programs written for machine execution will always be susceptible to information theft. This information can include trademarked algorithms, data embedded in the program, or even data the program accesses. As technology advances computer scientists are building more and more powerful tools for reverse-engineering such as decompilers.The Java programming language is particularly open to reverse-engineering attacks because of its well-defined, open, and portable binary format. We examine one area of better-securing the intellectual property of a Java program; obfuscation. Obfuscation of a program involves transforming the code of the program into a more complex, but semantically equivalent representation. This can include the addition of confusing control flow, the removal of certain information embedded in the program which is not explicitly required for execution, or the cloaking of data.Obfuscation is one of the only techniques available other than cryptological options. While many approaches to obfuscation are ultimately reversible, it nevertheless seriously hinders those attempting to steal information by increasing the computing time and power required by software to reverse-engineer the program and also severely increases the complexity of any source code that is recovered by the reverse-engineering.In this thesis we present a number of obfuscating transformations implemented within a new automatic tool we name the Java Bytecode Obfuscator (JBCO). We present empirical measures of the performance costs of these transformations in terms of execution speed and program size. Complexity measurements that gauge the effectiveness of the obfuscations are also given. Finally, we review the feasibility of each transformation by looking at source code generated from obfuscated bytecode by various decompilers.Les programmes écrits pour l'exécution d'ordinateur seront toujours susceptibles au vol d'information. Cette information peut inclure des algorithmes de marque de commerce, des données incluses dans le programme, ou même des données concernant les accès de programme. Suivant les avancées technologiques, les informaticiens construisent des outils de plus en plus puissants pour l'ingénierie inverse telle que le décompilateur. Le langage de programmation de Java est particulièrement ouvert aux attaques de l'ingénierie inverse en raison de son format binaire bien défini, ouvert, et portatif. Nous recherches portent sur un domaine permettant de mieux sécuriser fixer la propriété intellectuelle des programmes en Java; obscurcissement. L'obscurcissement d'un programme implique de transformer le code du programme en une représentation plus complexe mais sémantiquement équivalente. Ceci peut inclure l'addition de l'écoulement embrouillant de commande, de la supression de certaines informations incluses dans les programmes dont l'exécution n'est pas spécifiquement exigée, ou de la dissimulation des données. Excepté les techniques cryptologique s, l'obscurcissement est l'une des seules techniques disponibles. Même si beaucoup de stratégies de l'obscurissment sont finalement réversibles, il gêne sérieusement ceux qui essayent de voler l'information en augmentant la durée de calcul et la puissance exigées par les logicels d'ingénierie inverse et augmente considérablement la complexité de n'importe quel code source récupere par cette technique. Dans cette thèse nous présentons un certain nombre de transformations d'obscurcissement mises en application dans un outil automatique que nous appelons le Java Bytecode Obfuscator (JBCO). Nous présentons des mesures empiriques des coûts d'exécution de ces transformations en termes de vitesse d'exécution et taille de programme. Des mesures de complexité qui mesurent l'efficacité des obscurc
3
ARVIDSSON, OSKAR. "Platform Independent Code Obfuscation." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-146986.
Full textAbstract:
Code obfuscation is a technique used to make soft- ware more difficult to read and reverse engineer. It is used in the industry to protect proprietary algo- rithms and to protect the software from unintended use. The current state of the art solutions in the in- dustry depend on specific platform targets. In this report we look at code obfuscation from a platform independent point of view. The result is a survey of code obfuscation methods that can be used together to perform platform independent code obfuscation. We also analyze some of these methods in more de- tail and provide insights regarding their potency (dif- ficulty to deobfuscate manually), resilience (difficulty to deobfuscate automatically), stealth (difficulty to distinguish from normal code) and ease of integra- tion (how easily the method can be integrated and used in a toolchain).Kodobfuskering är ett verktyg för att göra mjukvara svårare att läsa, förstå och bakåtkompilera. Det an- vänds inom industrin för att skydda proprietära algo- ritmer samt för att skydda program och tjänster från att missbrukas. De lösningar som finns att tillgå idag är dock ofta beroende av en eller flera specifika platt- formar. I den här rapporten undersöker vi möjlighe- ten att göra plattformsoberoende obfuskering. Resul- tatet är en undersökning av vilka obfuskeringsmeto- der som finns tillgängliga, samt en djupare studie av några av dessa. Den djupare studien ger, för var och en av de studerade metoderna, insikter om hur svåra de är att deobfuskera för hand, hur svåra de är att deobfuskera automatiskt, hur pass svårt det är att skilja den obfuskerade koden från den oobfuskerade, samt hur lätt det är att implementera och integrera dem i en kompileringskedja.
4
ARVIDSSON, OSKAR. "Platform Independent Code Obfuscation." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-142031.
Full text
5
Varia, Mayank (Mayank Harshad). "Studies in program obfuscation." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/64489.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 159-164).
Program obfuscation is the software analog to the problem of tamper-proofing hardware. The goal of program obfuscation is to construct a compiler, called an "obfuscator," that garbles the code of a computer program while maintaining its functionality. Commercial products exist to perform this procedure, but they do not provide a rigorous security guarantee. Over the past decade, program obfuscation has been studied by the theoretical cryptography community, where rigorous definitions of security have been proposed and obfuscators have been constructed for some families of programs. This thesis presents three contributions based on the virtual black-box security definition of Barak et al [10]. First, we show tight connections between obfuscation and symmetric-key encryption. Specifically, obfuscation can be used to construct an encryption scheme with strong leakage resilience and key-dependent message security. The converse is also true, and these connections scale with the level of security desired. As a result, the known constructions and impossibility results for each primitive carry over to the other. Second, we present two new security definitions that augment the virtual black-box property to incorporate non-malleability. The virtual black-box definition does not prevent an adversary from modifying an obfuscated program intelligently. By contrast, our new definitions provide software with the same security guarantees as tamper-proof and tamper-evident hardware, respectively. The first definition prohibits tampering, and the second definition requires that tampering is detectable after the fact. We construct non-malleable obfuscators of both favors for some program families of interest. Third, we present an obfuscator for programs that test for membership in a hyperplane. This generalizes prior works that obfuscate equality testing. We prove the security of the obfuscator under a new strong variant of the Decisional Diffie-Hellman assumption that holds in the generic group model. Additionally, we show a cryptographic application of the new obfuscator to leak-ageresilient one-time digital signatures. The thesis also includes a survey of the prior results in the field.
by Mayank Varia.
Ph.D.
6
KUMAR, AMIT. "CONTROL FLOW OBFUSCATION COMPLEXITY." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1116221965.
Full text
7
Duchene, Julien. "Développement et évaluation d'obfuscations de protocoles basées sur la spécification." Electronic Thesis or Diss., Toulouse, INSA, 2018. http://www.theses.fr/2018ISAT0054.
Full textAbstract:
Il existe de plus en plus de protocoles de communications différents. La spécification de beaucoup d’entre eux est disponible. Cependant, quand il s’agit de moyens de communication propriétaires, cette spécification est gardée secrète : un attaquant qui aurait accès à cette spécification pourrait compromettre un système utilisant ce protocole. Même s’il n’a pas accès à cette spécification, l’attaquant peut l’obtenir par rétro-conception. Ainsi, il est intéressant de créer des protocoles qui sont difficiles à rétro-concevoir. Dans cette thèse, nous proposons une nouvelle approche spécifiquement développée pour rendre complexe la rétro-conception de protocole. Nous appliquons pour cela des obfuscations au format du message et ceci de façon automatique à partir de la spécification du protocole. Pour cela, nous avons dans un premier temps étudié plus de 30 contributions différentes concernant des outils de rétro-conception de protocole et en avons tiré des conclusions suivantes : 1) les outils de rétro-conception de protocole pratiquent l’inférence de modèles réguliers ; 2) ils supposent que le parsing d’un message s’effectue de gauche à droite ; 3) ils délimitent le message en champs d’après des délimiteurs bien connus ou via des algorithmes ad-hoc ; 4) ils regroupent les messages d’après des mesures de similarité sur des patterns. Ainsi, pour créer un protocole difficile à rétro-concevoir, une solution est de s’assurer que le protocole ne respecte pas ces conditions. Dans un second temps, nous avons donc proposé un modèle de format de messages qui permet l’application d’obfuscations. Nous avons défini des obfuscations atomiques qui peuvent être composées. Chacune de ces obfuscations cible une ou plusieurs des hypothèses des outils de rétro-conception. La composition des obfuscations assure l’efficacité de notre solution et rend la rétro-conception de protocole complexe. Ce modèle est utilisé pour générer automatiquement le code du parseur, du sérialiseur et des accesseurs. Cette solution est implémentée dans un prototype nommé ProtoObf grâce auquel nous avons pu évalué les performances des obfuscations. Les résultats montrent une nette augmentation de la complexité de la rétro-conception avec le nombre de compositions d’obfuscation tandis que les coûts induits (particulièrement la taille du buffer sérialisé) restent basThere are more and more protocols. Many of them have their specification available for interoperability purpose for instance. However, when it comes to intellectual property, this specification is kept secret. Attackers might use a wrongly implemented protocol to compromise a system, if he has access to the specification, it’s attack would be far more efficient. Even if he does not have access to the specification, he can reverse-engine it. Thus, create protocols hard to reverse is interesting. In this thesis, we develop a novel approach of protocol protections to make protocol reverse engineering more complex. We apply some obfuscations on protocol message format, furthermore, we do it automatically from the original protocol specification. Firstly, we have analyzed more than 30 different contributions of protocol reverse engineering tools. We retrieved the following elements : 1) Protocol reverse engineering tools try to infer regular models ; 2) They suppose that the parsing is done from left to right ; 3) They delimit fields based on well-known delimiters or with ad-hoc techniques ; 4) They cluster messages based on pattern similarity measures. Thus, to make protocol reverse harder, one can create protocols which does not respect theses statements. Secondly, we have proposed a model of message format on which obfuscations can be applied. With this model, we also provide some atomic obfuscations which can be composed. Each obfuscation target one or more protocol reverse engineering hypothesis. Obfuscation composition ensures effectiveness of our solution and makes protocol reverse-engineering more complex. This model is used to automatically generate code for parser, serializer and accessors. This solution is implemented into a framework we called ProtoObf. ProtoObf is used to evaluate obfuscations performance. Results show an increase of protocol complexity with the number of obfuscation composition while costs (particularly the serialized buffer size) stay low
8
Chakraborty, Rajat Subhra. "Hardware Security through Design Obfuscation." Cleveland, Ohio : Case Western Reserve University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1270133481.
Full textAbstract:
Thesis (Doctor of Philosophy)--Case Western Reserve University, 2010Department of EECS - Computer Engineering Title from PDF (viewed on 2010-05-25) Includes abstract Includes bibliographical references and appendices Available online via the OhioLINK ETD Center
9
Drape, Stephen. "Obfuscation of abstract data-types." Thesis, University of Oxford, 2004. http://ora.ox.ac.uk/objects/uuid:fa574ce9-4ed2-41f5-86d8-78113828b9ab.
Full text
10
Sethi, Amit. "Digital Rights Management and Code Obfuscation." Thesis, University of Waterloo, 2004. http://hdl.handle.net/10012/1012.
Full textAbstract:
Digital Rights Management (DRM) involves retaining control over digital information, even after it has been made public. Preventing illegal file sharing on the Internet, which is a topic that has recently received a large amount of media attention, is just one instance where DRM is needed.
In this thesis, we attempt to create formal definitions for DRM. Currently, there is a lack of such formal definitions, which is one reason why DRM schemes have achieved little success. We will also examine two DRM schemes that can be cracked easily: Microsoft DRM 2. 0, and the Content Scrambling System. We then discuss the reasons why DRM schemes have been unsuccessful so far, and why a good DRM scheme must incorporate secure hardware, secure software, and an efficient legal system. We also briefly discuss several issues related to DRM, such as privacy.
Code Obfuscation involves hiding a program's implementation details from an adversary. One application of code obfuscation involves hiding cryptographic keys in encryption and decryption programs for a cryptosystem. Code obfuscation is directly applicable to DRM schemes, where the adversary has access to a program that contains secret information. For example, a music player may contain a secret key that it uses to decrypt content. The secret key must be hidden from the adversary, since otherwise, he/she could use the key to write his/her own decryption program, and distribute it to circumvent the DRM scheme.
We discuss the proof from Barak et al that shows that code obfuscation is impossible in general. This, however, does not mean that code obfuscation cannot be achieved in specific cases. We will examine an obfuscated version of the Data Encryption Standard, and discuss the circumstances under which it is insecure. We also examine a toy example of a block cipher called Simple Block Cipher (SBC), and apply obfuscation techniques to SBC to hide the secret key, and then attempt to obtain the secret key.
11
Mohsen, Rabih. "Quantitative measures for code obfuscation security." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/55180.
Full textAbstract:
In this thesis we establish a quantitative framework to measure and study the security of code obfuscation, an effective software protection method that defends software against malicious reverse engineering. Despite the recent positive result by Garg et al.[GGH+13] that shows the possibility of obfuscating using indistinguishability obfuscation definition, code obfuscation has two major challenges: firstly, the lack of theoretical foundation that is necessary to define and reason about code obfuscation security; secondly, it is an open problem whether there exists security metrics that measure and certify the current state-of-the-art of code obfuscation techniques. To address these challenges, we followed a research methodology that consists of the following main routes: a formal approach to build a theory that captures, defines and measures the security of code obfuscation, and an experimental approach that provides empirical evidence about the soundness and validity of the proposed theory and metrics. To this end, we propose Algorithmic Information Theory, known as Kolmogorov complexity, as a theoretical and practical model to define, study, and measure the security of code obfuscation. We introduce the notion of unintelligibility, an intuitive way to define code obfuscation, and argue that it is not sufficient to capture the security of code obfuscation. We then present a more powerful security definition that is based on the algorithmic mutual information, and show that is able to effectively capture code obfuscation security. We apply our proposed definition to prove the possibility of obtaining security in code obfuscation under reasonable assumptions. We model adversaries with deobfuscation capabilities that explicitly realise the required properties for a successful deobfuscation attack. We build a quantitative model that comprises a set of security metrics, which are derived from our proposed theory and based on lossless compression, aiming to measure the quality of code obfuscation security. We propose normalised information distance NID as a metric to measure code obfuscation resilience, and establish the relation between our security definition and the normalised information distance. We show that if the security conditions for code obfuscations are satisfied (the extreme case) then the NID tends to be close to one, which is the maximum value that can be achieved. Finally, we provide an experimental evaluation to provide empirical validation for the proposed metrics. Our results show that the proposed measures are positively correlated with the degree of obfuscation resilience to an attacker using decompilers, i.e. the percentage of the clear code that was not recovered by an attacker, which indicates a positive relationship with the obfuscation resilience factor.
12
Holmgren, Justin Lee. "Succinct garbled RAM from indistinguishablity obfuscation." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/100600.
Full textAbstract:
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 83-86).
In this thesis, I give the first construction of a succinct garbling scheme for RAM programs. For a program requiring space S and time T to compute, the size of its garbling is Õ(S) instead of poly(T). This construction relies on the existence of indistinguishability obfuscation, as well as the existence of injective one-way functions. As a building block, I introduce and construct a primitive called asymmetrically constrained encryption (ACE). This primitive is an encryption system for which keys can be punctured on succinctly described sets of plaintexts. For programs acting on ACE-encrypted values, I give a natural and general condition for their obfuscations to be indistinguishable, using the fact that the encryption and decryption keys can be separately punctured. This succinct garbling scheme serves as a drop-in replacement for the ubiquitous garbled circuits of Yao, but with better asymptotic parameters. In some cases, these improved parameters allow qualitatively new applications.
by Justin Lee Holmgren.
M. Eng.
13
Lombardi, Alex (Alex John). "Low complexity pseudorandom generators and indistinguishability obfuscation." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/118056.
Full textAbstract:
Thesis: S.M. in Computer Science and Engineering, Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 61-64).
In the study of cryptography in NCO, it was previously known that Goldreich's candidate pseudorandom generator (PRG) is insecure when instantiated with a predicate P in 4 or fewer variables, if one wants to achieve polynomial stretch. On the other hand, there is a standard candidate PRG with locality 5 based on the "tri-sum-and" predicate ... However, locality is only one complexity measure of a PRG that one could hope to minimize. In this work, we consider the problem of minimizing three other complexity measures of a (local) PRG: decision tree (DT-)complexity, Q-degree (i.e., the degree of P as a polynomial over Q), and the recent notion of blockwise locality (due to Lin and Tessaro). These three complexity measures are all of interest for their possible applications to constructing indistinguishability obfuscation (IO) schemes based on low-degree multilinear maps. Indeed, Lin and Tessaro recently proposed an intriguing candidate IO scheme based on bilinear maps and a non-standard assumption on "Goldreich-like" pseudorandom generators. We obtain both positive and negative results on the existence of low complexity PRGs. First, we give a candidate predicate for Goldreich's PRG with DT-complexity 4 and Q-degree 3. We also show that all predicates with either DT-complexity less than 4 or Q-degree less than 3 yield insecure PRGs, so our candidate predicate simultaneously achieves the best possible locality, DT-complexity, Q-degree, and F2-degree according to all known attacks. Finally, we show polynomial-time attacks on the blockwise 2-local PRGs required in the Lin-Tessaro work, invalidating the security of their IO and FE candidates based on bilinear maps. Our attack uses tools from the literature on two-source extractors (Chor and Goldreich, SICOMP 1988) and efficient refutation of random 2-XOR instances (Charikar and Wirth, FOCS 2004).
by Alex Lombardi.
S.M. in Computer Science and Engineering
14
Shruti, Banda. "Complexity and obfuscation in evolving platform pricing." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/118561.
Full textAbstract:
Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, System Design and Management Program, February 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 62-65).
Two-sided platforms include some of the largest and fastest-growing businesses of the past decade. They are composed of three parts: two distinct groups of end-users and a platform. Two-sided platforms face unique challenges such as design, pricing, governance rules etc. The pricing decision specifically has been the subject of rigorous research. As the value that each group derives from using the platform depends on the size of the other side of the market, the platform's pricing strategies of the two groups are closely linked. A platform pricing strategy includes decisions about which side of the platform to charge, how much to charge them and an overall approach to attract and benefit both sides of the platform. Though the study of platform strategies has been quite popular among many economists, they have focused on analyzing the strategies from a static perspective. Because platforms have evolved their pricing strategies over time to be competitive in the market and have faced challenges, the process deserves attention. This thesis therefore analyzes the evolution of pricing strategies of platforms such as eBay (sellers and buyers) and Uber (riders and drivers) and the challenges they overcame to stay ahead in the market. We study that eBay initially used a complex pricing strategy but simplified it to compete in the market with Amazon and other e-commerce firms. Uber, in contrast, began with a simple "taxi-meter" pricing but changed their pricing strategy to account for the multiple variables such as demand, supply, location etc. The study concludes that to stay relevant in the market and to be successful, platforms need to evolve their pricing strategy over time depending on various market conditions. Though there is not one fixed pattern of how platforms evolve their pricing, their strategies consider simplicity, data availability and transparency while making pricing decisions. Future platforms can use these learnings while designing their pricing strategies.
by Banda Shruti.
S.M. in Engineering and Management
15
Degwekar, Akshay (Akshay Dhananjai). "Structure vs. hardness through the obfuscation lens." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/105578.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 71-[77]).
Cryptography relies on the computational hardness of structured problems. While one-way functions, the most basic cryptographic object, does not seem to require much structure, as we advance up the ranks into public-key cryptography and beyond, we seem to require that certain structured problems are hard. For example, factoring, quadratic residuosity, discrete logarithms, and approximate shortest and closest vectors in lattices all have considerable algebraic structure. This structure, on the one hand, enables useful applications such as public-key and homomorphic encryption, but on the other, also puts their hardness in question. Their structure is exactly what puts them in low complexity classes such as SZK or NP [set-theoretic intersection symbol] coNP, and is in fact the reason behind (sub-exponential or quantum) algorithms for these problems. The question is whether such structure is inherent in different cryptographic primitives, deeming them inherently easier. We study the relationship between two structured complexity classes, statistical zero-knowledge (SZK) and NP [set-theoretic intersection symbol] coNP, and cryptography. To frame the question in a meaningful way, we rely on the language of black-box constructions and separations. Our results are the following: -- Cryptography vs. Structured Hardness: Our two main results show that there are no black-box constructions of hard problems in SZK or NP [set-theoretic intersection symbol] coNP starting from one of a wide variety of cryptographic primitives such as one-way and trapdoor functions, one-way and trapdoor permutations (in the case of SZK), public-key encryption, oblivious transfer, deniable encryption, functional encryption, and even indistinguishability obfuscation; -- Complexity-theoretic Implications: As a corollary of our result, we show a separation between SZK and NP[set-theoretic intersection symbol]coNP and the class PPAD that captures the complexity of computing Nash Equilibria; and -- Positive Results: We construct collision-resistant hashing from a strong form of SZK-hardness and indistinguishability obfuscation. It was previously known that indistinguishability obfuscation by itself does not imply collision-resistant hashing in a black-box way; we show that it does if one adds SZK-hardness as a "catalyst". Our black-box separations are derived using indistinguishability obfuscation as a "gateway", by first showing a (separation) result for indistinguishability obfuscation and then leveraging on the fact that indistinguishability obfuscation can be used to construct the above variety of cryptographic primitives and hard PPAD instances in a black-box manner.
by Akshay Degwekar.
S.M.
16
Rodriguez, Perdomo Carlos Mario. "Designing interactions for data obfuscation in IoT." Thesis, Malmö högskola, Fakulteten för kultur och samhälle (KS), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-22494.
Full textAbstract:
This project explores the internet of things (IoT) at home, especially the aspects related to the quantity and the quality of the of data collected by the smart devices and the violation of the users’ privacy this situation represents, since with the help of machine learning algorithms, these devices are capable of storing and analysing information related to the daily routine of each user at home. Therefore, this research enquires new ways to raise the user's’ awareness about the flow of the data within the IoT at home in order to empower them and give them back the status of administrators of this context by designing devices that are capable of obfuscating the data before it leaves the home.During this process, several methods were used together in order to reach the outcomes. From the use of annotated portfolios to evaluate the state of the art related with the field, to video sketching as a useful and quick tool to embrace the user’s perspective in parallel with the use of cultural probes in order to test some conceptual scenarios and find new ways to explore this project based on the experiences of the participants.As a result, this project’s outcome is based on the use of the materialization of the data as the proper way to bring the abstract process that happens in the background closer to the user's reality in order to display how this data is actually flowing through the environment and at the end generate a calltoaction to guide the user into the execution of the obfuscation of the data.This project opens up the discussion within the interaction design field about the way we are communicating with the technology and if it is the proper way to do it when this technology coexist with the user at home. Additionally, it questions the way in which the interfaces should be designed in order to create a transparent dialogue between the users, the objects and the vendors.
17
Ferla, Daniele. "ROPfuscator: machine code obfuscation through Return Oriented Programming." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/17539/.
Full textAbstract:
La protezione del software da attacchi di reverse engineering, atti a violarne la proprietà intellettuale, `e diventata una priorità assoluta per le aziende produttrici di soluzioni informatiche: dilatare il tempo richiesto per ottenere informazioni cruciali sul funzionamento interno di un programma può giocare un ruolo determinante in termini di profitti generabili. Allo stato dell’arte, soluzioni per l’offuscamento di programmi sono presenti in letteratura e utilizzano un’ampia varietà di tecniche per raggiungere lo scopo.
In questo lavoro di tesi viene presentata l’implementazione di un offuscatore che impiega Return Oriented Programming (ROP) - da cui il nome -, una tecnica ampiamente utilizzata nell’ambito dell’exploit development, ma poco approfondita nel campo della software obfuscation. Vengono inoltre presentate delle innovative metodologie per aumentare l’efficacia dell’offuscamento: symbol anchoring, per referenziare ROP gadget in memoria nonostante il binario di appartenenza sia allocato in memoria in una locazione non-deterministica, e gadget generalisation, per consentire il riutilizzo di ROP gadget anche con operandi differenti.
18
Rahbari, Hanif. "Obfuscation of Transmission Fingerprints for Secure Wireless Communications." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/612371.
Full textAbstract:
Our world of people and objects is on the verge of transforming to a world of highly-interconnected wireless devices. Incredible advances in wireless communications, hardware design, and power storage have facilitated hasty spread of wireless technologies in human life. In this new world, individuals are often identified and reached via one or multiple wireless devices that they always carry (e.g., smartphones, smart wearable, implantable medical devices, etc.), and their biometrics identities are replaced by their digital fingerprints. In near future, vehicles will be controlled and monitored via wireless monitoring systems and various physical objects (e.g., home appliance and retail store items) will be connected to the Internet. The list of these changes goes on. Unfortunately, as different aspects of our lives are being immerged in and dependent to wireless devices and services, we will become more vulnerable to wireless service/connection interruptions due to adversarial behavior and our privacy will become more potent to be exposed to adversaries. An adversary can learn the procedures of a wireless system and analyze its stages, and accordingly, launch various attacks against the operations of the system or the privacy of the people. Existing data confidentiality and integrity services (e.g., advanced encryption algorithms) have been able to prevent the leakage of users' messages. However, in wireless networks, even when upper-layer payloads are encrypted, the users' privacy and the operation of a wireless network can be threatened by the leakage of transmission attributes at the physical (PHY) layer. Examples of these attributes are payload size, frequency offset (FO), modulation scheme, and the transmission rate. These attributes can be exploited by an adversary to launch passive or active attacks. A passive attacker may learn about the interests, sexual orientation, political views, and patentable ideas of the user through analyzing these features, whereas an active attacker exploits captured attributes to launch selective packet jamming/dropping and disrupt wireless services. These call for novel privacy preserving techniques beyond encryption. In this dissertation, we study the vulnerability of current wireless systems to the leakage of transmission attributes at the PHY layer and propose several schemes to prevent it. First, we design and experimentally demonstrate with USRPs an energy-efficient and highly disruptive jamming attack on the FO estimation of an OFDM system. OFDM is the core multiplexing scheme in many modern wireless systems (e.g., LTE/5G and 802.11a/n/ac) and is highly susceptible to FO. FO is the difference in the operating frequencies of two radio oscillators. This estimation is done by the receiver using the publicly-known frame preamble. We show that the leakage of FO value via the preamble can facilitate an optimally designed jamming signal without needing to know the channel between the transmitter and the legitimate receiver. Our results show that the jammer can guarantee a successful attack even when its power is slightly less than the transmitter's power. We then propose four mitigation approaches against the proposed FO attack. Next, we consider certain transmission attributes that are disclosed via unencrypted PHY/MAC headers. Example of these attributes are payload size, transmission rate, and MAC addresses. Beyond unencrypted headers, the adversary can estimate the frame size and transmission rate through identifying the payload's modulation scheme and measuring the transmission time. To prevent the leakage of these attributes, we propose Friendly CryptoJam scheme, which consists of three components: First, a modulation-aware encryption scheme to encrypt the headers. Second, an efficient modulation obfuscation techniques. Specifically, the proposed modulation obfuscation scheme embeds the modulation symbols of a frame's payload into the constellation of the highest-order modulation scheme supported by the system. Together with effective PHY/MAC header encryption at the modulation level, the proposed obfuscation scheme hides the transmission rate, payload size, and other attributes announced in the headers while avoiding any BER performance loss. Compared with prior art, Friendly CryptoJam enjoys less complexity and less susceptibility to FO estimation errors. The third component is a novel PHY-level identification method. To facilitate PHY/MAC header encryption when a MAC layer sender identifier cannot be used (e.g., due to MAC address encryption), we propose two preamble-based sender identification methods, one for OFDM and one for non-OFDM systems. A sender identifier is special message that can be embedded in the frame preamble. The extent of the applications of our embedding scheme goes beyond identifier embedding and include embedding part of the data frame, the sender's digital signature, or any meta-data that the sender provides. Our message embedding method can further be used to mitigate the FO estimation attack because the jammer can no longer optimize its jamming signal with respect to a fixed preamble signal. In addition, we considered friendly jamming technique in a multi-link/hop network to degrade the channels of the eavesdroppers and prevent successful decoding of the headers, while minimizing the required jamming power by optimally placing the friendly jamming devices.
19
Aravalli, SaiKrishna. "Some Novice methods for Software Protection with Obfuscation." ScholarWorks@UNO, 2006. http://scholarworks.uno.edu/td/479.
Full textAbstract:
Previously software is distributed to the users by using devices like CD.S and floppies and in the form of bytes. Due to the high usage of internet and in order to perform the tasks rapidly without wasting time on depending physical devices, software is supplied through internet in the form of source code itself. Since source code is available to the end users there is a possibility of changing the source code by malicious users in order to gain their personnel benefits which automatically leads to malfunctioning of the software. The method proposed in this thesis is based on the concept of using hardware to protect the software. We will obfuscate the relation between variables and statements in the software programs so that the attacker can not find the direct relation between them. The method combines software security with code obfuscation techniques, uses the concepts of cryptography like hashing functions and random number generators.
20
Wang, Yan. "Obfuscation-Resilient Code Detection Analyses for Android Apps." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1534337202264542.
Full text
21
Graux, Pierre. "Challenges of native android applications : obfuscation and vulnerabilities." Thesis, Rennes 1, 2020. http://www.theses.fr/2020REN1S047.
Full textAbstract:
Android est le système d'exploitation le plus utilisé et donc, assurer la sécurité des applications est essentiel. Sécuriser une application consiste à empêcher les attaquants potentiels de corrompre le comportement attendu de l'application. En particulier, l'attaquant peut s'appuyer sur des vulnérabilités laissées dans le code par le développeur, mais aussi voler la propriété intellectuelle d'une application existante. Pour ralentir le travail de l'attaquant qui essaie de reverser la logique applicative, le développeur est incité à chercher les vulnérabilités potentielles et à introduire des contremesures dans le code. Parmi les contremesures possibles, l'obfuscation de code est une technique qui cache l'intention réelle du développeur en faisant en sorte de rendre le code non disponible à l'adversaire qui utilise des outils de reverser. Avec l'augmentation des applications soit malveillantes, soit manipulant des informations sensibles, obfusquer le code et chercher ses vulnérabilités devient essentiel. Cette thèse présente l'impact du code natif sur, à la fois le reversing et la recherche de vulnérabilités, appliqué à des applications Android. Premièrement, en listant les interférences possibles entre l'assembleur et le bytecode, nous mettons en évidence des nouvelles techniques d'obfuscation et vulnérabilités logicielles. Ensuite, nous proposons de nouvelles techniques d'analyse combinant des blocs d'analyse statiques et dynamiques, tels que la propagation de teintes ou la surveillance du système, afin d'observer le comportement du code qui a été obfusqué ou de révéler de nouvelles vulnérabilités. Ces deux objectifs nous ont menés à développer deux nouveaux outils. Le premier cible une vulnérabilité spécifique due à l'interaction du natif et des données Java. Le second extrait le comportement d'une application au niveau objet, que l'application contienne du code natif d'obfuscation ou non. Enfin, nous avons implémenté ces nouvelles méthodes et les avons évaluées expérimentalement. En particulier, nous avons trouvé automatiquement une vulnérabilité dans la librairie SSL d'Android et nous avons analysé plusieurs firmware Android pour détecter l'usage d'une classe spécifique d'obfuscationAndroid is the most used operating system and thus, ensuring security for its applications is an essential task. Securing an application consists in preventing potential attackers to divert the normal behavior of the targeted application. In particular, the attacker may take advantage of vulnerabilities left by the developer in the code and also tries to steal intellectual property of existing applications. To slow down the work of attackers who try to reverse the logic of a released application, developers are incited to track potential vulnerabilities and to introduce countermeasures in the code. Among the possible countermeasures, the obfuscation of the code is a technique that hides the real intent of the developer by making the code unavailable to an adversary using a reverse engineering tool. With the growing amount of malware and applications carrying sensitive information, obfuscating the code and searching vulnerabilities becomes essential. This thesis presents the impact of native code on both reverse-engineering and vulnerability finding applied to Android applications. First, by listing the possible interferences between assembly and bytecode, we highlight new obfuscation techniques and software vulnerabilities. Then, we propose new analysis techniques combining static and dynamic analysis blocks, such as taint tracking or system monitoring, to observe the code behaviors that have been obfuscated or to reveal new vulnerabilities. These two objectives have led us to develop two new tools. The first one spots a specific vulnerability that comes from inconsistently mixing native and Java data. The second one extracts the object level behavior of an application, regardless of whether this application contains native code, embedded for obfuscation purposes. Finally, we implemented these new methods and conducted experimental evaluations. In particular, we automatically found a vulnerability in the Android SSL library and we analyzed several Android firmware to detect usage of a specific class of obfuscation
22
Coogan, Kevin Patrick. "Deobfuscation of Packed and Virtualization-Obfuscation Protected Binaries." Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/202716.
Full textAbstract:
Code obfuscation techniques are increasingly being used in software for such reasons as protecting trade secret algorithms from competitors and deterring license tampering by those wishing to use the software for free. However, these techniques have also grown in popularity in less legitimate areas, such as protecting malware from detection and reverse engineering. This work examines two such techniques - packing and virtualization-obfuscation - and presents new behavioral approaches to analysis that may be relevant to security analysts whose job it is to defend against malicious code. These approaches are robust against variations in obfuscation algorithms, such as changing encryption keys or virtual instruction byte code.Packing refers to the process of encrypting or compressing an executable file. This process "scrambles" the bytes of the executable so that byte-signature matching algorithms commonly used by anti-virus programs are ineffective. Standard static analysis techniques are similarly ineffective since the actual byte code of the program is hidden until after the program is executed. Dynamic analysis approaches exist, but are vulnerable to dynamic defenses. We detail a static analysis technique that starts by identifying the code used to "unpack" the executable, then uses this unpacker to generate the unpacked code in a form suitable for static analysis. Results show we are able to correctly unpack several encrypted and compressed malware, while still handling several dynamic defenses.Virtualization-obfuscation is a technique that translates the original program into virtual instructions, then builds a customized virtual machine for these instructions. As with packing, the byte-signature of the original program is destroyed. Furthermore, static analysis of the obfuscated program reveals only the structure of the virtual machine, and dynamic analysis produces a dynamic trace where original program instructions are intermixed, and often indistinguishable from, virtual machine instructions. We present a dynamic analysis approach whereby all instructions that affect the external behavior of the program are identified, thus building an approximation of the original program that is observationally equivalent. We achieve good results at both identifying instructions from the original program, as well as eliminating instructions known to be part of the virtual machine.
23
DALLA, PREDA Mila. "Code obfuscation and malware detection by abstract interpretation." Doctoral thesis, Università degli Studi di Verona, 2007. http://hdl.handle.net/11562/337972.
Full textAbstract:
Non disponibileAn obfuscating transformation aims at confusing a program in order to make it more difficult to understand while preserving its functionality. Software protection and malware detection are two major applications of code obfuscation. Software developers use code obfuscation in order to defend their programs against attacks to the intellectual property, usually called malicious host attacks. In fact, by making the programs more difficult to understand it is possible to obstruct malicious reverse engineering – a typical attack to the intellectual property of programs. On the other side, malware writers usually obfuscate their malicious code in order to avoid detection. In this setting, the ability of code obfuscation to foil most of the existing detection techniques, such as misuse detection algorithms, relies in their purely syntactic nature that makes malware detection sensitive to slight modifications of programs syntax. In the software protection scenario, researchers try to develop sophisticated obfuscating techniques that are able to resist as many attacks as possible. In the malware detection scenario, on the other hand, it is important to design advanced detection algorithms in order to detect as many variants of obfuscated malware as possible. It is clear how both malicious host and malicious code attacks represent harmful threats to the security of computer networks. In this dissertation, we are interested in both security issues described above. In particular, we describe a formal approach to code obfuscation and malware detection based on program semantics and abstract interpretation. This theoretical framework is useful in contrasting some well known drawbacks of software protection through code obfuscation, as well as for improving existing malware detection schemes. In fact, the lack of rigorous theoretical bases for code obfuscation prevents any possibility to formally study and certify their effectiveness in protecting proprietary programs. Moreover, in order to design malware detection schemes that are resilient to obfuscation we have to focus on program semantics rather than on program syntax. Our formal framework for code obfuscation relies on a semantics-based definition of code obfuscation that characterizes each program transformation T as a potential obfuscation in terms of the most concrete property preserved by T on program semantics. Deobfuscating techniques, and reverse engineering in general, usually begin with some sort of static program analysis, which can be specified as an abstraction of program semantics. In the software protection scenario, this observation naturally leads to model attackers as abstractions of program semantics. In fact, the abstraction modeling the attacker expresses the amount of information, namely the semantic properties, that the attacker is able to observe. It follows that, comparing the degree of abstraction of an attacker A with the one of the most concrete property preserved by an obfuscating transformation T, it is possible to understand whether obfuscation T defeats attack A. Following the same reasoning it is possible to compare the efficiency of different obfuscating transformations, as well as the ability of different attackers in contrasting a given obfuscation. We apply our semantics-based framework to a known control code obfuscation technique that aims at confusing the control flow of the original program by inserting opaque predicates. As argued above, an obfuscating transformation modifies a program while preserving an abstraction of its semantics. This means that different obfuscated versions of the same malware have to share (at least) the malicious intent, namely the maliciousness of their semantics, even if they may express it through different syntactic forms. The basic idea of our formal approach to malware detection is to use program semantics to model both malware and program behaviour, and semantic abstractions to hide the details changed by the obfuscation. Thus, given an obfuscation T, we are interested in defining an abstraction of program semantics that does not distinguish between the semantics of malware M and the semantics of its obfuscated version T(M). In particular, we provide this suitable abstraction for an interesting class of commonly used obfuscating transformations. It is clear that, given a malware detector D, it is always possible to define its semantic counterpart by analyzing how D works on program semantics. At this point, by translating both malware detectors and obfuscating transformations in the semantic world, we are able to certify which obfuscations a detector is able to handle. This means that our semanticsbased framework provides a formal setting where malware detectors designers can prove the efficiency of their algorithms.
24
Tauman, Kalai Yael. "Attacks on the Fiat-Shamir paradigm and program obfuscation." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/34026.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 115-119).
The goal of cryptography is to construct *secure* and *efficient* protocols for various tasks. Unfortunately, it is often the case that protocols that are provably secure are not efficient enough for practical use. As a result, most protocols used in practice are *heuristics* that lack proofs of security. These heuristics are typically very efficient and are believed to be secure, though no proof of security has been provided. In this thesis we study the security of some of these popular heuristics. In particular, we focus on two types of heuristics: (1) the Fiat-Shamir heuristic for constructing digital signature schemes, and (2) heuristics for obfuscation. We show that, in some sense, both of these types of heuristics are insecure. Thus, this thesis consists of two parts: (1) The insecuirty of the Fiat-Shamir paradigm: The Fiat-Shamir heuristic provides a general method for transforming secure 3-round public-coin identification schemes into digital signature schemes. The idea of the transformation is to replace the random (second-round) message of the verifier in the identification scheme, with the value of some deterministic hash function evaluated on the first-round message (sent by the prover) and on the message to be signed.
(cont.) The Fiat-Shamir methodology for producing digital signature schemes quickly gained popularity both in theory and in practice, as it yields efficient and easy to implement digital signature schemes. The most important question however remained open: are the digital signature schemes produced by the Fiat-Shamir methodology secure? In this thesis, we answer this question negatively. We show that there exist secure 3-round public-coin identification schemes for which the Fiat-Shamir transformation yields *insecure* digital signature schemes for *any* hash function used by the transformation. This is in contrast to the work of Pointcheval and Stern, who proved that the Fiat-Shamir methodology always produces digital signature schemes that are secure against chosen message attacks in the ``Random Oracle Model" -- when the hash function is modeled by a random oracle. (2) The impossibility of obfuscation: The goal of code obfuscation is to make a program completely "unintelligible" while preserving its functionality. Obfuscation has been used for many years in attempts to prevent reverse engineering, e.g ., in copy protection, licensing schemes, and games.
(cont.) As a result, many heuristics for obfuscation have emerged, and the important question that remained is: are these heuristics for obfuscation secure? In this thesis, we show that there are many "natural" classes of functions for which obfuscation is not at all possible. This impossibility result holds in an augmentation of the formal obfuscation model of Barak, et al. (2001) that includes auxiliary input. In both of these parts, among other tools, we make new usage of Barak's technique for taking advantage of non black-box access to a program, this time in the context of digital signature schemes and in the context of obfuscation.
by Yael Tauman Kalai.
Ph.D.
25
Lu, Weiyun. "Formally Verified Code Obfuscation in the Coq Proof Assistant." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39994.
Full textAbstract:
Code obfuscation is a software security technique where transformations are applied
to source and/or machine code to make them more difficult to analyze and understand
to deter reverse-engineering and tampering. However, in many commercial tools, such
as Irdeto's Cloakware product, it is not clear why the end user should believe that
the programs that come out the other end are still the same program"!
In this thesis, we apply techniques of formal specification and verification, by
using the Coq Proof Assistant and IMP (a simple imperative language within it), to
formulate what it means for a program's semantics to be preserved by an obfuscating
transformation, and give formal machine-checked proofs that these properties hold.
We describe our work on opaque predicate and control flow flattening transformations.
Along the way, we also employ Hoare logic as an alternative to state equivalence,
as well as augment the IMP program with Switch statements. We also define a lower-level flowchart language to wrap around IMP for modelling certain flattening
transformations, treating blocks of codes as objects in their own right.
We then discuss related work in the literature on formal verification of data obfuscation
and layout obfuscation transformations in IMP, and conclude by discussing
CompCert, a formally verified C compiler in Coq, along with work that has been done
on obfuscation there, and muse on the possibility of implementing formal methods in
the next generation of real-world obfuscation tools.
26
Parameswaran, Rupa. "A Robust Data Obfuscation Technique for Privacy Preserving Collaborative Filtering." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11459.
Full textAbstract:
Privacy is defined as the freedom from unauthorized intrusion. The availability of personal information through online databases, such as government records, medical records, and voters and #146; lists, pose a threat to personal privacy. The concern over individual privacy has led to the development of legal codes for safeguarding privacy in several countries. However, the ignorance of individuals as well as loopholes in the systems, have led to information breaches even in the presence of such rules and regulations. Protection against data privacy requires modification of the data itself. The term {em data obfuscation} is used to refer to the class of algorithms that modify the values of the data items without distorting the usefulness of the data. The main goal of this thesis is the development of a data obfuscation technique that provides robust privacy protection with minimal loss in usability of the data.
Although medical and financial services are two of the major areas where information privacy is a concern, privacy breaches are not restricted to these domains. One of the areas where the concern over data privacy is of growing interest is collaborative filtering. Collaborative filtering systems are being widely used in E-commerce applications to provide recommendations to users regarding products that might be of interest to them. The prediction accuracy of these systems is dependent on the size and accuracy of the data provided by users. However, the lack of sufficient guidelines governing the use and distribution of user data raises concerns over individual privacy. Users often provide the minimal information that is required for accessing these E-commerce services. The lack of rules governing the use and distribution of data disallows sharing of data among different communities for collaborative filtering. The goals of this thesis are (a) the definition of a standard for classifying DO techniques, (b) the development of a robust cluster preserving data obfuscation algorithm, and (c) the design and implementation of a privacy-preserving shared collaborative filtering framework using the data obfuscation algorithm.
27
Desai, Avinash R. "Anti-Counterfeit and Anti-Tamper Hardware Implementation using Hardware Obfuscation." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/23756.
Full textAbstract:
Tampering and Reverse Engineering of a chip to extract the hardware Intellectual Property
(IP) core or to inject malicious alterations is a major concern. First, offshore chip manufac-
turing allows the design secrets of the IP cores to be transparent to the foundry and other
entities along the production chain. Second, small malicious modifications to the design
may not be detectable after fabrication without anti-tamper mechanisms. Counterfeit Inte-
grated Circuits (ICs) also have become an important security issue in recent years, in which
counterfeit ICs that perform incorrectly or sub-par to the expected can lead to catastrophic
consequences in safety and/or mission-critical applications, in addition to the tremendous
economic toll they incur to the semiconductor industry. Some techniques have been devel-
oped in the past to improve the defense against such attacks but they tend to fall prey to
the increasing power of the attacker. We present a new way to protect against tampering
by a clever obfuscation of the design, which can be unlocked with a specific, dynamic path
traversal. Hence, the functional mode of the controller is hidden with the help of obfuscated
states, and the functional mode is made operational only on the formation of a specific
interlocked Code-Word during state transition. A novel time-stamp is proposed that can
provide the date at which the IC was manufactured for counterfeit detection. Furthermore,
we propose a second layer of tamper resistance to the time-stamp circuit to make it even
more difficult to modify. Results show that methods proposed offer higher levels of security
with small area overhead. A side benefit is that any small alteration will be magnified via
the obfuscated design proposed in these methods.Master of Science
28
Makin, Cameron. "Primary User Obfuscation in an Incumbent Informed Spectrum Access System." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/104015.
Full textAbstract:
With a growing demand for spectrum availability, spectrum sharing has become a high-profile solution to overcrowding. In order to enable spectrum sharing between incumbent/primary and secondary users, incumbents must have spectrum protection and privacy from malicious new entrants. In this Spectrum Access System (SAS) advancement, Primary Users (PUs) are obfuscated with the efforts of the SAS and the cooperation of obedient new entrants. Further, the necessary changes to the SAS to support this privacy scheme are exposed to suggest improvements in PU privacy, Citizens Broadband Radio Service Device (CBSD)-SAS relations, and punishment for unauthorized transmission. Results show the feasibility for PU obfuscation with respect to malicious spectrum sensing users. Simulation results indicate that the obfuscation scheme can deliver location and frequency occupation privacy with 75% and 66% effectiveness respectively in a 100% efficient spectrum utilization oriented obfuscation scheme. A scheme without spectrum utilization constraint shows up to 91% location privacy effectiveness. Experiment trials indicate that the privacy tactic can be implemented on an open-source SAS, however environmental factors may degrade the tactic's performance.Master of Science
With a growing demand for spectrum availability, wireless spectrum sharing has become a high-profile solution to spectrum overcrowding. In order to enable spectrum sharing between incumbent/primary (e.g.,federal communications, naval radar, users already grandfathered into the band) and secondary users (e.g., commercial communications companies), incumbents must have spectrum protection and privacy from malicious new entrants. In this Spectrum Access System (SAS) advancement, Primary Users (PUs) are obfuscated with the efforts of the incumbent informed SAS and the cooperation of obedient new entrants. Further, the necessary changes to the SAS to support this privacy scheme are exposed to suggest improvements in PU privacy, Citizens Broadband Radio Service Device (CBSD)-SAS relations, and punishment for unauthorized transmission. Results show the feasibility of PU obfuscation with respect to malicious spectrum sensing users. Simulation results indicate that the obfuscation tactic can deliver location and frequency occupation privacy with 75% and 66% effectiveness respectively in a 100% efficient spectrum utilization oriented obfuscation scheme. A scheme without spectrum utilization constraint shows up to 91% location privacy effectiveness. Experiment trials indicate that the privacy tactic can be implemented on an open-source SAS, however environmental factors may degrade the tactic's performance.
29
Kandikonda, Balausha Varshini. "A Key Based Obfuscation and Anonymization of Behavior VHDL Models." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7686.
Full textAbstract:
Intellectual Property (IP) based Integrated Circuit (IC) design is an established approach for the design of a complex System-on-Chip (SoC). Porting the preparatory designs to third-party without enough security margin exposes an attacker to perform reverse engineering (RE) on the designs and hence counterfeiting, IP theft etc., are common now-a-days. Design obfuscation can reduce RE attempt by an attacker. In this work, we propose a key based obfuscation and anonymization method for a behavioral IP. Given a behavioral VHDL description, the assignment and conditional statements are modified by incorporating random boolean operations with unique random key bits. The obfuscated VHDL is then anonymized by random identifiers. The resultant behavioral model can be simulated correctly upon application of original key sequence. Simulation results with nine datapath intensive benchmarks with three different lengths of test sequences show that the simulation overhead is negligible (only a few seconds). We evaluate the probability of reverse engineering the obfuscated design and show that it is extremely low.
30
Riaud, Stéphanie. "Obfuscation de données pour la protection de programmes contre l'analyse dynamique." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S167.
Full textAbstract:
La rétro-conception est une technique qui consiste à analyser un produit afin d'en extraire un secret. Lorsque le produit ciblé est un programme informatique, le rétro-concepteur peut chercher à extraire un algorithme ou tout élément du code de ce programme. L'obfuscation est une technique de protection qui consiste à modifier le code d'un programme afin de le rendre plus difficile à rétro-concevoir. Nous nous intéressons à l'étude et au développement de techniques d'obfuscation de programmes informatiques. Nous avons développé une nouvelle technique d'obfuscation de code, puis nous avons démontré son efficacité et finalement nous avons implémenté une autre technique de protection ayant pour objectif de renforcer la résilience des techniques de protection anti-rétro conception. Nous avons donc, dans un premier temps, imaginé et implémenté une nouvelle technique d'obfuscation permettant de protéger certains éléments spécifiques contenus dans les programmes implémentés en langage C. En nous appuyant sur un état de l'art détaillé des techniques d'analyses utilisées lors de la rétro-conception de programmes, nous avons établi l'efficacité de cette technique de protection. Dans un second temps, nous avons étayé les éléments précédemment établis, en démontrant de façon empirique que cette mesure de protection peut être appliquée sur des programmes concrets. Nous démontrons qu'elle peut être mise en place sur des codes de haut niveau et rester efficace sur les fichiers exécutables obtenus à partir de ces codes. Nous poussons notre analyse jusqu'à démontrer que lorsque le processus d'obfuscation est réalisé de façon scrupuleuse, le temps d'exécution des programmes protégés reste dans le même ordre de grandeur que celui des programmes non protégés. Dans un troisième temps, nous travaillons en avance de phase en développant des mécanismes de protection ciblés, visant à contrer les outils d'analyse automatique utilisés par les rétro-concepteurs. Leur objectif est de renforcer la robustesse des techniques appliquées à haut niveau en augmentant leur furtivité et en fournissant au rétro-concepteur des résultats erronés. Nos contributions couvrent divers sujets liés à la lutte contre la rétro-conception. Nous avons développé et implémenté de nouvelles techniques de protection de code. Lorsque ces techniques de protection s'appliquent à haut niveau, nous avons mis au point un processus permettant de démontrer qu'elles ne perdent pas en efficacité et que leur coût en terme de temps d'exécution reste acceptable. Pour les techniques de protection plus bas niveau que nous avons développées, nous avons démontré leur efficacité face à des outils d'analyse dynamique de code utilisés lors de la rétro-conceptionReverse engineering is a technique that consists in analyzing a product in order to extract a secret. When a computer program is targeted, the reverse engineer may seek to extract an algorithm code or any component of this program. Obfuscation is a protection technique aimed to make it more difficult to reverse engineer. We are interested in the study and development of obfuscation techniques to protect computer programs. We have developed a new technique of code obfuscation, then we have demonstrated its effectiveness, and finally we implemented another protection technique with the aim of enhance the resilience of anti-reverse engineering protection techniques. So we, initially, designed and implemented a new obfuscation technique to protect certain specific elements contained in the programs implemented in C language. By relying on dynamic analysis techniques, we have established the effectiveness of this protection technique. Secondly, we have backed up previously established elements, by demonstrating empirically that this protection can be applied to concrete programs. We demonstrate that this protection can be placed on high-level codes and remain effective on executable files obtained from these codes. We demonstrate that when the process of obfuscation is realized in a scrupulous way, the execution time of programs remains in the same order as that of the protected programs. Thirdly, we work on developing targeted protection mechanisms to counter automatic analysis tools used by reverse engineers. Their aim is to enhance the robustness of the techniques applied to high level by increasing their stealth and providing fake results for the reverse engineers. Our contributions cover various topics related to protection against reverse engineering. We have developed and implemented new code protection techniques. When these protection techniques are apply to high level, we have developed a process to demonstrate that they do not lose efficiency and their cost in terms of execution time remains acceptable. For the lowest level protection techniques that we have developed, we have demonstrated their effectiveness face of dynamic code analysis tools used in reverse engineering
31
WERKELIN, AHLIN OSKAR. "Implementation and evaluation of some platformindependent obfuscating transformations." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-142376.
Full textAbstract:
We study the state-of-art of code obfuscation, a technique used to protect software from reverse engineering by complicating the execution flow of a program. The best current solutions are platform dependent. Platform independent code obfuscation techniques are evaluated by implementing specific code obfuscation methods, and comparing their efficiency with respect to a number of defined metrics. The obfuscation methods are implemented tightly coupled with a common open source compiler. We conclude that the choice is good and gives a lot of freedom in implementing an obfuscator. We successfully implement and evaluate some obfuscation methods, which alone are not that potent, but when applied in chain with other methods can make the job harder for a reverse engineer.Vi studerar kodobfuskering, ett verktyg som används för att skydda mjukvara från att bakåtkompileras. När man obfuskerar programkod så komplicerar man exekveringsflödet och gör det på så sätt svårare för angripare eller konkurrenter att tyda den bakomliggande logiken hos programmet. Dagens bästa lösningar för kodobfuskering är beroende av en viss plattform. Vi utvärderar några plattformsoberoende obfuskeringsalgoritmer genom att implementera dem och utvärdera dem med avseende på ett antal definierade mätvärden. Obfuskeringsmetoderna implementeras med hjälp av ett vanligt kompilatorprojekt som baseras på öppen källkod. Vi konstaterar att det är gynnsamt att göra implementationerna på valt sätt. Givet implementationen av några vanliga obfuskeringsmetoder så utvärderar vi dem var för sig, och ensamma visar de sig inte vara så kraftfulla som förväntat. Vi kan dock konstatera att obfuskeringsmetoderna kan bli mycket mer kraftfulla om de appliceras i kombination med varandra.
32
Kuseler, Torben. "Localisation and obfuscation techniques for enhanced multi-factor authentification in mcommerce applications." Thesis, University of Buckingham, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.573423.
Full textAbstract:
Abstract The focus of this thesis is to investigate solutions that shall enhance the security of remote client authentication for mCommerce applications on phones such as Smartphones or Tablet-PCs. This thesis details three innovative authentication schemes developed during the course of this study. These schemes are based on the use of localisation and obfuscation techniques in combination with multi-factor authentication to enforce the knowledge of "who, when, where and how" necessary for any remote client authentication attempt. Thus, assuring the mCommerce service provider about the genuine client as well as ensuring correct capturing and processing of the client's authentication data on the remote phone. The author of this thesis believes that these schemes, when developed on commercial mCommerce applications, shall enhance the service provider's trust into the received client data and therefore shall encourage more service providers to offer their mCommerce services via phone applications to their clients. The first proposed scheme, called MORE-BAILS, combines multiple authentication factors into a One-Time Multi-Factor Biometric Representation (OTMFBR) of a client, so to achieve robust, secure, and privacy-preserving client authentication. Tests and trials of this scheme proved that it is viable for use in the authentication process of any type of mCommerce phone applications. The second and third schemes, called oBiometrics and LocAuth respectively, use a new obfuscated-interpretation approach to protect the mComrnerce application against misuse by attackers as well as to ensure the real-time and one-time properties of the client's authentication attempt. The novelty of combining biornetric-based keys with obfuscated-interpretation tightly binds the correct mCommerce application execution to the genuine client. Furthermore, integration of the client's current location and real-time in the LocAuth challenge / response scheme eliminates the risk that an attacker can illegitimately re-use previously gathered genuine client authentication data in a replay attack. f Based on appropriate criteria, the MORE-BAILS, oBiometrics and LocAuth levels of security, user-friendliness and algorithms' ease-of-implementation are proven m experiments and trials on state-of-the-art Android-based Smartphones.
33
Edwards, Robert Andrew. "Essays in industrial organisation : price competition, strategic obfuscation, advertising & consumer behaviour." Thesis, University of Liverpool, 2017. http://livrepository.liverpool.ac.uk/3007004/.
Full text
34
Zabransky, Douglas Milton. "Incorporating Obfuscation Techniques in Privacy Preserving Database-Driven Dynamic Spectrum Access Systems." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/85001.
Full textAbstract:
Modern innovation is a driving force behind increased spectrum crowding. Several studies performed by the National Telecommunications and Information Administration (NTIA), Federal Communications Commission (FCC), and other groups have proposed Dynamic Spectrum Access (DSA) as a promising solution to alleviate spectrum crowding. The spectrum assignment decisions in DSA will be made by a centralized entity referred to as as spectrum access system (SAS); however, maintaining spectrum utilization information in SAS presents privacy risks, as sensitive Incumbent User (IU) operation parameters are required to be stored by SAS in order to perform spectrum assignments properly. These sensitive operation parameters may potentially be compromised if SAS is the target of a cyber attack or an inference attack executed by a secondary user (SU).
In this thesis, we explore the operational security of IUs in SAS-based DSA systems and propose a novel privacy-preserving SAS-based DSA framework, Suspicion Zone SAS (SZ-SAS), the first such framework which protects against both the scenario of inference attacks in an area with sparsely distributed IUs and the scenario of untrusted or compromised SAS. We then define modifications to the SU inference attack algorithm, which demonstrate the necessity of applying obfuscation to SU query responses. Finally, we evaluate obfuscation schemes which are compatible with SZ-SAS, verifying the effectiveness of such schemes in preventing an SU inference attack. Our results show SZ-SAS is capable of utilizing compatible obfuscation schemes to prevent the SU inference attack, while operating using only homomorphically encrypted IU operation parameters.Master of Science
35
Hendrikse, Steven. "The Effect of Code Obfuscation on Authorship Attribution of Binary Computer Files." NSUWorks, 2017. http://nsuworks.nova.edu/gscis_etd/1009.
Full textAbstract:
In many forensic investigations, questions linger regarding the identity of the authors of the software specimen. Research has identified methods for the attribution of binary files that have not been obfuscated, but a significant percentage of malicious software has been obfuscated in an effort to hide both the details of its origin and its true intent. Little research has been done around analyzing obfuscated code for attribution. In part, the reason for this gap in the research is that deobfuscation of an unknown program is a challenging task. Further, the additional transformation of the executable file introduced by the obfuscator modifies or removes features from the original executable that would have been used in the author attribution process. Existing research has demonstrated good success in attributing the authorship of an executable file of unknown provenance using methods based on static analysis of the specimen file. With the addition of file obfuscation, static analysis of files becomes difficult, time consuming, and in some cases, may lead to inaccurate findings. This paper presents a novel process for authorship attribution using dynamic analysis methods. A software emulated system was fully instrumented to become a test harness for a specimen of unknown provenance, allowing for supervised control, monitoring, and trace data collection during execution. This trace data was used as input into a supervised machine learning algorithm trained to identify stylometric differences in the specimen under test and provide predictions on who wrote the specimen. The specimen files were also analyzed for authorship using static analysis methods to compare prediction accuracies with prediction accuracies gathered from this new, dynamic analysis based method. Experiments indicate that this new method can provide better accuracy of author attribution for files of unknown provenance, especially in the case where the specimen file has been obfuscated.
36
Eyrolles, Ninon. "Obfuscation par expressions mixtes arithmético-booléennes : reconstruction, analyse et outils de simplification." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLV031/document.
Full textAbstract:
L'obfuscation de logiciels est une technique de protection deprogrammes qui transforme du code pour rendre son analyse plusdifficile. Les expressions mixtes arithmético-booléennes (MBA) sontprésentées comme une bonne obfuscation du flot de données. Le domainede l'obfuscation MBA étant assez jeune, il bénéficie de peu delittérature sur la conception et l'analyse de telles expressionsobfusquées. Ainsi, beaucoup de sujets intéressants apparaissent lors deson étude, autant sur l'obfuscation que sur la désobfuscation (ousimplification) d'expressions MBA.Durant nos recherches, nous avons structuré le sujet de l'obfuscationMBA, le reliant à d'autres domaines comme la cryptographie ou laréécriture. Nous avons également reconstruit une techniqued'obfuscation MBA à partir d'échantillons publics. Nous avons étudié ce quesignifie simplifier une expression obfusquée, et défininos propres métriques de simplicité pour les expressions MBA. L'étudede la simplification MBA a entraîné l'implémentation de deux outils dedésobfuscation, qui ont simplifié avec succès plusieurs examplespublics d'expressions obfusquées. Finalement, nous avons évalué larésilience de l'obfuscation MBA par rapport à nos algorithmes desimplification (ainsi que d'autres techniques de désobfuscation), etnous avons conclu que la technique d'obfuscation MBA offrait peu derésilience en l'état. Nous avons donc proposé quelques pistes pouraméliorer ce type d'obfuscationSoftware obfuscation is a software protection technique thattransforms code in order to make its analysis more difficult. MixedBoolean-Arithmetic (MBA) expressions are presented as a strongobfuscation in the context of data flow obfuscation. As the domainaround MBA obfuscation is quite young, there is little literatureon the conception and analysis of such obfuscated expressions.Therefore many interesting subjects arise during its study, both around theobfuscation and deobfuscation (or simplification) of MBA expressions.During our work, we structured the subject of MBA obfuscation, linkingit to other topics like cryptography or rewriting. We also reconstructedan MBA obfuscation technique from public samples. We studied themeaning of simplifying an obfuscated expression, and definedour own simplicity metrics for MBA expressions. The study of MBAsimplification yielded the implementation of two deobfuscation toolsthat successfully simplified several public examples of obfuscatedexpressions. Finally, we assessed the resilience of the MBAobfuscation with regard to our simplification algorithms (as well asother deobfuscation techniques), concluding that this obfuscationtechnique offers little resilience as it is, and we proposed a few ideasto help improve this type of obfuscation
37
Kwon, Duke L. "Obfuscation and restoration Paul's use of Isaiah in 1 Corinthians 14:20-25 /." Theological Research Exchange Network (TREN) Access this title online, 2004. http://www.tren.com.
Full text
38
Wainwright, Edward. "Transparency and obfuscation : politics and architecture in the work of Foster & Partners." Thesis, Cardiff University, 2010. http://orca.cf.ac.uk/55462/.
Full textAbstract:
This dissertation examines the obfuscatory potential of transparency in the work of architectural practice Foster & Partners. Transparency, as a narrative of Western culture, has been used unthinkingly and uncritically by architects to equate clarity with rationality, accessibility and democracy. Through a close analytical reading of the practice's output, using a framework which draws from Henri Lefebvre's The Production of Space (1974), Jean Baudrillard's Simulacra and Simulation (1981), Marshall McLuhan's Understanding Media (1964), and Reinhold Martin's The Organisational Complex (2003), the political, cultural and social significance of Foster & Partners' transparent architecture is discussed. The dissertation works with two definitions of transparency: one drawn from Foster & Partners' use of transparent techniques and rhetoric as found in their built and published work; one based on a critical approach to materials which locate the place of transparency in architectural and spatial history and theory. Three case-studies from the practice are read for their transparent capacity and are placed in their respective historical-geographical contexts, following the methods of David Harvey. These projects, The Palace of Peace and Concord in Kazakhstan (2004-2006); HACTL Super Terminal in Hong Kong (1992-1998); and the Philological Library of the Free University Berlin (1997-2005), are analysed to examine the technological, material, aesthetic, formal and spatial qualities of their organisation. By placing these projects in their respective contexts, the position of transparency as an active architectural and cultural device is discussed, and its role in shaping the structure of social, political and institutional forms is explored. The thesis concludes by questioning widespread assumptions in architecture and culture that transparency acts to open-up and decrypt the hidden.
39
Merkl-Davies, Doris. "The obfuscation hypothesis re-examined : analyzing impression management in corporate narrative report documents." Thesis, Bangor University, 2007. https://research.bangor.ac.uk/portal/en/theses/the-obfuscation-hypothesis-reexamined--analyzing-impression-management-in-corporate-narrative-report-documents(3fd58e2c-790a-44b7-80c8-2c4b41ef72c3).html.
Full textAbstract:
This thesis empirically investigates the use of impression management in the narrative sections of the annual reports of UK listed companies. Impression management is examined by testing the obfuscation hypothesis which claims that firms with poor performance have a tendency to obfuscate negative organisational outcomes. For this purpose, the thesis provides an assessment of the extent to which reading difficulty and self-presentational dissimulation are associated with the disclosure of favourable or unfavourable results ('good/bad news') in annual financial statements, conditional on a firm's size and sector of operations. Impression management has previously been studied in the context of agency theory explanations of managerial and investor behaviour. This study contributes to the understanding of impression management in a corporate reporting context by first reviewing relevant theoretical work in behavioural finance, social psychology, and linguistics. Social psychology provides additional insights into the managerial motivation to engage in impression management, the circumstances fostering managerial impression management, and preferred managerial strategies. Behavioural finance offers insights into the effectiveness of impression management. Research in linguistics and social psychology provides the basis for developing new methodologies for measuring impression management in corporate narrative documents which overcome the validity problems inherent in conventional measures. Three new methodologies are introduced. The first develops cohesion-based measures of reading difficulty that focus on grammatical devices within and between sentences, including the number and density of cohesive ties and the proportion of new and given information (MMAX2). The second methodology provides multiple cohesionbased measures of readability, as applied in web-based readability scoring (CohMetrix). The third methodology measures impression management in the form of selfpresentational dissimulation (i.e. portraying a public image of firm performance and prospects inconsistent with a managerial view of firm performance and prospects), using linguistic markers which include word count, self-reference, reference to others, the use of emotion words, and cognitive complexity. The empirical analysis that is reported in this thesis is based on a sample that is balanced across industrial sectors and representative of the size distribution of firms. Results show firm size and not 'good/bad news' to be the determining factor in reading difficulty. Although the main effects model shows 'bad news' to be directly related to reading difficulty, this association is no longer significant when 'good/bad news' is interacted with firm size. Results suggest that large firms are more likely to produce corporate narrative documents which are less cohesive (and thus more difficult to read) than small firms. This is not interpreted as impression management, but as an indication that firms might tailor their corporate narrative documents to the reading strategies of their target readership groups. Thus, large firms seem to cater to the needs of high-knowledge readers (professional investors or readers largely familiar with the infom1ation content of the chairman's report), and small firms to the needs of low-knowledge readers (individual investors or readers largely unfamiliar with the information content of the chairman's report). Results regarding impression management in the form of self-presentational dissimulation suggest that the linguistic markers are not indicative of impression management in the form of selfpresentational dissimulation, but of other psychological issues.
40
Карплюк, Володимир Ігорович, and Volodymyr Karpliuk. "Обфускаційні методи захисту програмного коду в комп’ютерних системах." Master's thesis, Тернопільський національний технічний університет імені Івана Пулюя, 2020. http://elartu.tntu.edu.ua/handle/lib/33269.
Full textAbstract:
Кваліфікаційну роботу магістра присвячено розробці обфускатора для
мови програмування JavaScript. Знайдено баланс між рівнем обфускації та
необхідною продуктивністю. Проведені дослідження допомогли підвищити
рівень захищеності інформації та програмних продуктів власними методами
обфускації. Здійснено аналіз готових рішень.
У роботі проведено оцінку вже існуючих методів та засобів обфускації,
знайдено оптимальні комбінації заплутуючих перетворень. Доведено
ефективність використання розробленого обфускатора.
Застосування розроблених обфускаційних технологій дасть змогу покращити такі показники
розробленого ПЗ як: стійкість, надійність, безпечність.Obfuscation methods of program code protection in computer systems // Master's qualification work // Karplyuk Volodymyr Ihorovych // Ternopil National Technical University, Department of Computer Systems and Networks, Computer Engineering, SIM-61 Group // Ternopil, 2020 / / P. - 83, fig. - 27, bibliogr. - 32, table. - 1. The master's thesis is devoted to the development of an obfuscator for the JavaScript programming language. A balance was found between the level of obfuscation and the required productivity. The research helped to increase the level of security of information and software products by their own methods of obfuscation. The analysis of ready decisions is carried out. The evaluation of already existing methods and means of obfuscation is carried out in the work, the optimal combinations of confusing transformations are found. The efficiency of using the developed obfuscator is proved. The application of the developed obfuscation technologies will allow to improve such indicators of the developed software as: stability, reliability, safety.
1.Аналіз уже існуючих технологій обфускації програмного коду. 2.Захист на апаратному та програмному рівнях. Оцінка якості обфускації. Дослідження методів обфускації на різних рівнях. 3.Розробка алгоритмів обфускатора. Реалізація власного програмного продукту для обфускації вихідного коду на мові програмування JavaScript.
41
Badier, Hannah. "Transient obfuscation for HLS security : application to cloud security, birthmarking and hardware Trojan defense." Thesis, Brest, École nationale supérieure de techniques avancées Bretagne, 2021. https://tel.archives-ouvertes.fr/tel-03789700.
Full textAbstract:
La mondialisation croissante de la chaîne d'approvisionnement des semi-conducteurs, ainsi que la complexité et la diversité croissantes des flux de conception de matériel, ont entraîné une recrudescence des menaces de sécurité : risques de vol et de revente de propriété intellectuelle, de rétro-ingénierie et d'insertion de code malveillant sous la forme de chevaux de Troie pendant la fabrication et au moment de la conception ont fait l'objet d'une recherche croissante ces dernières années. Cependant, les menaces lors de la synthèse de haut niveau (HLS), où une description algorithmique est transformée en une implémentation matérielle de niveau inférieur, n'ont été envisagées que récemment, et peu de solutions ont été proposées jusqu'à présent. Dans cette thèse, nous nous concentrons sur la sécurisation des conceptions lors de la synthèse comportementale à l'aide d'un outil HLS basé sur le cloud ou interne, mais non fiable. Nous introduisons une nouvelle méthode de protection au moment de la conception appelée offuscation, où le code source de haut niveau est obscurci à l'aide de techniques basées sur des clés, et désobscurci après HLS au niveau du transfert de registre. Cette méthode en deux étapes garantit une fonctionnalité de conception correcte et une faible surcharge de conception. Nous proposons trois façons d'intégrer l'offuscation transitoire dans différents mécanismes de sécurité. Tout d'abord, nous montrons comment il peut être utilisé pour empêcher le vol de propriété intellectuelle et la réutilisation illégale dans un scénario HLS basé sur le cloud. Ensuite, nous étendons ce travail au filigranes numériques, en exploitant les effets secondaires de l'offuscation transitoire sur les outils HLS pour identifier les conceptions volées. Enfin, nous montrons comment cette méthode peut également être utilisée contre les chevaux de Troie matériels, à la fois en empêchant l'insertion et en facilitant la détectionThe growing globalization of the semiconductor supply chain, as well as the increasing complexity and diversity of hardware design flows, have lead to a surge in security threats: risks of intellectual property theft and reselling, reverse-engineering and malicious code insertion in the form of hardware Trojans during manufacturing and at design time have been a growing research focus in the past years. However, threats during highlevel synthesis (HLS), where an algorithmic description is transformed into a lower level hardware implementation, have only recently been considered, and few solutions have been given so far. In this thesis, we focus on how to secure designs during behavioral synthesis using either a cloud-based or an internal but untrusted HLS tool. We introduce a novel design time protection method called transient obfuscation, where the high-level source code is obfuscated using key-based techniques, and deobfuscated after HLS at register-transfer level. This two-step method ensures correct design functionality and low design overhead. We propose three ways to integrate transient obfuscation in different security mechanisms. First, we show how it can be used to prevent intellectual property theft and illegal reuse in a cloud-based HLS scenario. Then, we extend this work to watermarking, by exploiting the side-effects of transient obfuscation on HLS tools to identify stolen designs. Finally, we show how this method can also be used against hardware Trojans, both by preventing insertion and by facilitating detection
42
Lukšas, Darius. "Programinio kodo obfuskacija ir įgyvendinimo metodai." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2006. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2006~D_20060114_012503-75154.
Full textAbstract:
The purpose of this project was to analyze and compare Microsoft Framework .NET (CLR type) files and their obfuscation methods, create the obfuscation system, using some of the analyzed methods. After analyzing different Microsoft Framework .NET obfuscation techniques in this project: • class, method, parameters name change; • user string encryption; • IL code encryption; Decision was made to use obfuscation method with class, method, parameters name change.
43
Lu, Gen. "Analysis of Evasion Techniques in Web-based Malware." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/312567.
Full textAbstract:
Web-based mechanisms, often mediated by malicious JavaScript code, play an important role in malware delivery today, making defenses against web-based malware crucial for system security. To make it even more challenging, malware authors often take advantage of various evasion techniques to evade detection. As a result, a constant arms race of evasion and detection techniques between malware authors and security analysts has led to advancement in code obfuscation and anti-analysis techniques. This dissertation focuses on the defenses against web-based malware protected by advanced evasion techniques from both defensive and offensive perspectives. From a defensive perspective, we examine existing evasion techniques and propose deobfuscation and detection approaches to defeating some popular techniques used by web-based malware today. In the case of code-unfolding based obfuscation, we use a semantics-based approach to simplify away obfuscations by identifying code that is relevant to the behavior of the original program. In the case of environment-dependent malware, we propose environmental predicate, which detects behavior discrepancy of JavaScript program between targeted browser and detector sandbox, therefore protecting users from possible detection false negatives caused by environmental triggers. From an offensive perspective, we analyze existing detection techniques to examining their assumptions and study how these assumptions can be broken. We also propose a combination of obfuscation and anti-analysis techniques, targeting these limitations, which can hide existing web-based malware from state-of-the-art detectors.
44
Cakmak, Ozan. "PRIVACY PRESERVATION IN A HYBRID MULTI MESH-LTE AMI NETWORK FOR SMART GRID." OpenSIUC, 2015. https://opensiuc.lib.siu.edu/theses/1720.
Full textAbstract:
While the newly envisioned Smart(er) Grid (SG) will result in a more efficient and reliable power grid, its collection and use of fine-grained meter data has widely raised concerns on consumer privacy. While a number of approaches are available for preserving consumer privacy, these approaches are mostly not very practical to be used due to two reasons: First, since the data is hidden, this reduces the ability of the utility company to use the data for distribution state estimation. Secondly and more importantly, the approaches were not tested under realistic wireless infrastructures that are currently in use. In this thesis, a meter data obfuscation approach to preserve consumer privacy is proposed to implement that has the ability to perform distribution state estimation. Then, its performance on LTE and a large-scale Advanced Metering Infrastructure (AMI) network built upon the new IEEE 802.11s wireless mesh standard are assessed. LTE/EPC(Evolved Packet Core) model is used between the gateway and the utility. EPC's goal is to improve network performance by the separation of control and data planes and through a flattened IP architecture, which reduces the hierarchy between mobile data elements. Using obfuscation values provided via this approach, the meter readings are obfuscated to protect consumer privacy from eavesdroppers and the utility companies while preserving the utility companies' ability to use the data for state estimation.The impact of this approach on data throughput, delay and packet delivery ratio under a variety of conditions are assessed.
45
Beussink, Andrew. "Preserving Consumer Privacy on IEEE 802.11s-Based Smart Grid AMI Networks." OpenSIUC, 2014. https://opensiuc.lib.siu.edu/theses/1383.
Full textAbstract:
While the newly envisioned smart grid will result in a more efficient and reliable power grid, its use of fine-grained meter data has widely raised concerns of consumer privacy. This thesis implements a data obfuscation approach to preserve consumer privacy and assesses its feasibility on a large-scale advanced metering infrastructure (AMI) network built upon the new IEEE 802.11s wireless mesh standard. This obfuscation approach preserves consumer privacy from eavesdroppers and the utility companies while preserving the utility companies' ability to use the fine-grained meter data for state estimation. The impact of this privacy approach is assessed based on its impact on data throughput and delay performance. Simulation results have shown that the approach is feasible to be used even when the network size grows. Additional adaptations to the approach are analyzed for their feasibility in further research.
46
Howard, Adam. "Obfuscation by Design: How Visual ComComplexity and Cognitive Bias Shape Our Understanding of Political Information." Research Showcase @ CMU, 2011. http://repository.cmu.edu/theses/8.
Full textAbstract:
There is a growing body of research on the ways in which people process and organize political information. However, these studies have focused almost exclusively on textual analysis at a time when people are turning to more visually oriented media in increasing numbers. While researchers have failed to account for this trend, political organizations have quickly adapted and begun to use visual media to their advantage for political messaging. This study examines people’s ability to perceive bias in visual representations of political information. Through a series of surveys and one-on-one interviews, I found that participants exhibited significant confirmation bias in their assessments of visual information. This effect was particularly strong in participants’ initial assessment of each example. The results reveal two potential paths to increasing awareness of bias in visual information. First, basic training in visual design could encourage more thorough examination of new information and result in increased awareness of bias. Second, illustrating the effects of confirmation bias could encourage viewers to pause and reassess their initial reaction to information, again resulting in increased awareness of bias. With these two hypotheses in mind, I have created an interactive guide that teaches basic elements of visual design, such as size and color, and then illustrates the effects of cognitive biases on assessment of information.
47
Zhuang, Yan [Verfasser], and Felix [Gutachter] Freiling. "Methods for Improving the Quality of Software Obfuscation for Android Applications / Yan Zhuang ; Gutachter: Felix Freiling." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2017. http://d-nb.info/1140917110/34.
Full text
48
Chilowicz, Michel. "Recherche de similarité dans du code source." Phd thesis, Université Paris-Est, 2010. http://tel.archives-ouvertes.fr/tel-00587628.
Full textAbstract:
La duplication de code source a de nombreuses origines : copie et adaptation inter-projets ou clonage au sein d'un même projet. Rechercher des correspondances de code copié permet de le factoriser dans un projet ou de mettre en évidence des situations de plagiat. Nous étudions des méthodes statiques de recherche de similarité sur du code ayant potentiellement subi des opérations d'édition telle que l'insertion, la suppression, la transposition ainsi que la factorisation et le développement de fonctions. Des techniques d'identification de similarité génomique sont examinées et adaptées au contexte de la recherche de clones de code source sous forme lexemisée. Après une discussion sur des procédés d'alignement de lexèmes et de recherche par empreintes de n-grams, est présentée une méthode de factorisation fusionnant les graphes d'appels de fonctions de projets au sein d'un graphe unique avec introduction de fonctions synthétiques exprimant les correspondances imbriquées. Elle utilise des structures d'indexation de suffixes pour la détermination de facteurs répétés. Une autre voie d'exploration permettant de manipuler de grandes bases indexées de code par arbre de syntaxe est abordée avec la recherche de sous-arbres similaires par leur hachage et leur indexation selon des profils d'abstraction variables. Des clones exacts de sous-arbres de forte proximité dans leurs arbres d'extraction peuvent alors être consolidés afin d'obtenir des correspondances approchées et étendues. En amont et en aval de la recherche de correspondances, des métriques de similarité sont définies afin de préselectionner les zones d'examen, affiner la recherche ou mieux représenter les résultats
49
Godfroy, Hubert. "Réflexion, calculs et logiques." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0130/document.
Full textAbstract:
Le but de cette thèse est de trouver des modèles de haut niveau dans lesquelles l'auto-modification s'exprime facilement. Une donnée est lisible et modifiable, alors qu'un programme est exécutable. On décrit une machine abstraite où cette dualité est structurellement mise en valeur. D'une part une zone de programmes contient tous les registres exécutables, et d'autre part une zone de données contient les registres lisibles et exécutables. L'auto-modification est permise par le passage d'un registre d'une zone à l'autre. Dans ce cadre, on donne une abstraction de l'exécution de la machine qui extrait seulement les informations d'auto-modification. Logiquement, on essaye de trouver une correspondance de Curry-Howard entre un langage avec auto-modification et un système logique. Dans ce but on construit une extension de lambda-calcul avec termes gelés, c'est à dire des termes qui ne peuvent se réduire. Ces termes sont alors considérés comme des données, et les autres sont les programmes. Notre langage a les propriétés usuelles du lambda-calcul (confluence). D'autre part, on donne un système de types dans lequel un sous ensemble des termes du langage peuvent s'exprimer. Ce système est inspiré de la Logique Linéaire, sans gestion des ressources. On prouve que ce système de types a de bonnes propriétés, comme celle de la réduction du sujet. Finalement, on étend le système avec les continuations et la double négation, dans un style à la KrivineThe goal of my Ph.D. is to finds high level models in which self-modification can be expressed. What is readable and changeable is a data, and a program is executable. We propose an abstract machine where this duality is structurally emphasized. On one hand the program zone beholds registers which can be executed, and on the other hand data zone contains readable and changeable registers. Self-modification is enabled by passing a data register into program zone, or a program register into data zone. In this case, we give an abstraction of executions which only extracts information about self-modifications: execution is cut into paths without self-modification. For the logical part, we tried to find a Curry-Howard correspondence between a language with self-modifications and logical world. For that we built an extension of lambda-calculus with frozen terms, noted , that is, terms which cannot reduce. This terms are considered as data. Other terms are programs. We first prove that this language as expected properties like confluence. On the other hand, we found a type system where a subset of terms of this language can be expressed. Our type system is inspired by Linear Logic, without resources management. We prove that this system has good properties like subject reduction. We finally have extended the system with continuation and double negation. This extension can be expressed in a krivine style, using a machine inspired by krivine machine
50
Ceder, Felicia, and Olivia Ahlmén. "Årsredovisningen, ett objektivt informationsdokument eller ett marknadsföringsverktyg? : En kvantitativ studie om läsbarheten i svenska börsnoterade företags årsredovisningar." Thesis, Linköpings universitet, Företagsekonomi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-148893.
Full textAbstract:
Bakgrund Årsredovisningens berättande delar utgör numera majoriteten av årsredovisningen. De berättande delarna hjälper läsaren att tolka den finansiella informationen. Därmed är läsbarheten i de berättande delarna viktig för årsredovisningens användbarhet. Tidigare studier har kommit fram till att företag medvetet försämrar årsredovisningens läsbarhet för att dölja skadlig information och därigenom vilseleda läsaren. Syfte Studiens syfte är att förklara variation i läsbarhet mellan svenska börsnoterade företags årsredovisningar. Metod Denna kvantitativa studie tar sin utgångspunkt i ett eklektiskt och deduktivt angreppssätt där både läsbarhets- och redovisningsteorier ligger till grund för hypotesutvecklingen. Studien utgår från en tvärsnittsdesign där studiens empiriska material utgörs av sekundärdata som är hämtad från företags årsredovisningar. Variation i årsredovisningars läsbarhet analyseras med multipel linjär regression. Slutsats Studiens resultat visar att det finns ett starkt positivt samband mellan lönsamhet och läsbarhet och således har mindre lönsamma företag en lägre läsbarhet i sina årsredovisningar. Resultatet påvisar även att det förekommer svaga skillnader i årsredovisningars läsbarhet mellan olika branscher. Vidare indikerar analysen att större företag skriver längre texter och därigenom mer svårläst.Introduction Nowdays the narrative parts are the majority of the annual report. The narrative parts help the reader to interpret the financial information. Thus, the readability is important for the usefulness of the annual report. Prior research has found that corporations strategically use the language as a tool to hide information and to obfuscate the reader. Purpose The purpose of this study is to explain variation in readability between Swedish listed corporations’ annual reports. Method This quantitative study is based on an eclectical and deductive approach where both theories of readability and accounting theories have formulated the hypotheses. A cross-sectional design has been used and the study's empirical data consist of secondary data, derived from annual reports. Variation in annual reports readability has been analysed by multiple linear regression. Conclusion The result shows that there is a strong positive correlation between profitability and readability, thus less profitable corporations have lower readability in their annual reports. The result also shows that there are weak differences in the annual reports' readability between different industries. Furthermore, the analysis indicates that larger companies write longer texts and thus more difficult.