CENSOR: Privacy-preserving Obfuscation for Outsourcing SAT formulas

We propose a novel obfuscation technique that can be used to outsource hard satisfiability (SAT) formulas to the cloud. Servers with large computational power are typically used to solve SAT instances that model real-life problems in task scheduling, AI planning, circuit verification and more. However, outsourcing data to the cloud may lead to privacy and information breaches since satisfying assignments may reveal considerable information about the underlying problem modeled by SAT. In this work, we develop CENSOR (privaCy prEserviNg obfuScation for Outsourcing foRmulas), a novel SAT obfuscation framework that resembles Indistinguishability Obfuscation. At the core of the framework lies a mechanism that transforms any formula to a random one with the same number of satisfying assignments. As a result, obfuscated formulas are indistinguishable from each other thus preserving the input-output privacy of the original SAT instance. Contrary to prior solutions that are rather adhoc in nature, we formally prove the security of our scheme. Additionally, we show that obfuscated formulas are within a polynomial factor of the original ones thus achieving polynomial slowdown. Finally, the whole process is efficient in practice, allowing solutions to original instances to be easily recovered from obfuscated ones. A byproduct of our method is that all NP problems can be potentially outsourced to the cloud by means of reducing to SAT

Cryptography

The Oberwolfach workshop Cryptography brought together scientists from cryptography with mathematicians specializing in the algorithmic problems underlying cryptographic security. The goal of the workshop was to stimulate interaction and collaboration that enables a holistic approach to designing cryptography from the mathematical foundations to practical applications. The workshop covered basic computational problems such as factoring and computing discrete logarithms and short vectors. It addressed fundamental research results leading to innovative cryptography for protecting security and privacy in cloud applications. It also covered some practical applications

Toward Securing Cloud-Based Data Analytics:A Discussion on Current Solutions and Open Issues

In the last few years, organizations and business professionals have realized the value of data analytics in supporting decision-making. Where several activities are performed on on-line data by different stakeholders, such as cleansing, aggregation, analysis and visualization, cloud-based data analytics has become a favored choice for business professionals due to the elasticity, availability, scalability, and pay-as-you-go features offered by cloud computing. However, large amounts of data stored on the cloud are very sensitive (e.g., innovation, financial, legal, customers’ data), and so data privacy remains one of the top concerns for many reasons;mainly those relating to legal or competition issues. In this paper, we review the security and cryptographic mechanisms which aim to make data analytics secure in a cloud environment, and discuss current research challenges

Hardening Circuit-Design IP Against Reverse-Engineering Attacks

Design-hiding techniques are a central piece of academic and industrial efforts to protect electronic circuits from being reverse-engineered. However, these techniques have lacked a principled foundation to guide their design and security evaluation, leading to a long line of broken schemes. In this paper, we begin to lay this missing foundation. We establish formal syntax for design-hiding (DH) schemes, a cryptographic primitive that encompasses all known design-stage methods to hide the circuit that is handed to a (potentially adversarial) foundry for fabrication. We give two security notions for this primitive: function recovery (FR) and key recovery (KR). The former is the ostensible goal of design-hiding methods to prevent reverse-engineering the functionality of the circuit, but most prior work has focused on the latter. We then present the first provably (FR,KR)-secure DH scheme, $\mathrm{OneChaff}_{\mathrm{hd}}$. A side-benefit of our security proof is a framework for analyzing a broad class of new DH schemes. We finish by unpacking our main security result, to provide parameter-setting guidance

A patient agent controlled customized blockchain based framework for internet of things

Although Blockchain implementations have emerged as revolutionary technologies for various industrial applications including cryptocurrencies, they have not been widely deployed to store data streaming from sensors to remote servers in architectures known as Internet of Things. New Blockchain for the Internet of Things models promise secure solutions for eHealth, smart cities, and other applications. These models pave the way for continuous monitoring of patient’s physiological signs with wearable sensors to augment traditional medical practice without recourse to storing data with a trusted authority. However, existing Blockchain algorithms cannot accommodate the huge volumes, security, and privacy requirements of health data. In this thesis, our first contribution is an End-to-End secure eHealth architecture that introduces an intelligent Patient Centric Agent. The Patient Centric Agent executing on dedicated hardware manages the storage and access of streams of sensors generated health data, into a customized Blockchain and other less secure repositories. As IoT devices cannot host Blockchain technology due to their limited memory, power, and computational resources, the Patient Centric Agent coordinates and communicates with a private customized Blockchain on behalf of the wearable devices. While the adoption of a Patient Centric Agent offers solutions for addressing continuous monitoring of patients’ health, dealing with storage, data privacy and network security issues, the architecture is vulnerable to Denial of Services(DoS) and single point of failure attacks. To address this issue, we advance a second contribution; a decentralised eHealth system in which the Patient Centric Agent is replicated at three levels: Sensing Layer, NEAR Processing Layer and FAR Processing Layer. The functionalities of the Patient Centric Agent are customized to manage the tasks of the three levels. Simulations confirm protection of the architecture against DoS attacks. Few patients require all their health data to be stored in Blockchain repositories but instead need to select an appropriate storage medium for each chunk of data by matching their personal needs and preferences with features of candidate storage mediums. Motivated by this context, we advance third contribution; a recommendation model for health data storage that can accommodate patient preferences and make storage decisions rapidly, in real-time, even with streamed data. The mapping between health data features and characteristics of each repository is learned using machine learning. The Blockchain’s capacity to make transactions and store records without central oversight enables its application for IoT networks outside health such as underwater IoT networks where the unattended nature of the nodes threatens their security and privacy. However, underwater IoT differs from ground IoT as acoustics signals are the communication media leading to high propagation delays, high error rates exacerbated by turbulent water currents. Our fourth contribution is a customized Blockchain leveraged framework with the model of Patient-Centric Agent renamed as Smart Agent for securely monitoring underwater IoT. Finally, the smart Agent has been investigated in developing an IoT smart home or cities monitoring framework. The key algorithms underpinning to each contribution have been implemented and analysed using simulators.Doctor of Philosoph

Aggregating privatized medical data for secure querying applications

 This thesis analyses and examines the challenges of aggregation of sensitive data and data querying on aggregated data at cloud server. This thesis also delineates applications of aggregation of sensitive medical data in several application scenarios, and tests privatization techniques to assist in improving the strength of privacy and utility

An investigation of issues of privacy, anonymity and multi-factor authentication in an open environment

This thesis performs an investigation into issues concerning the broad area ofIdentity and Access Management, with a focus on open environments. Through literature research the issues of privacy, anonymity and access control are identified. The issue of privacy is an inherent problem due to the nature of the digital network environment. Information can be duplicated and modified regardless of the wishes and intentions ofthe owner of that information unless proper measures are taken to secure the environment. Once information is published or divulged on the network, there is very little way of controlling the subsequent usage of that information. To address this issue a model for privacy is presented that follows the user centric paradigm of meta-identity. The lack of anonymity, where security measures can be thwarted through the observation of the environment, is a concern for users and systems. By an attacker observing the communication channel and monitoring the interactions between users and systems over a long enough period of time, it is possible to infer knowledge about the users and systems. This knowledge is used to build an identity profile of potential victims to be used in subsequent attacks. To address the problem, mechanisms for providing an acceptable level of anonymity while maintaining adequate accountability (from a legal standpoint) are explored. In terms of access control, the inherent weakness of single factor authentication mechanisms is discussed. The typical mechanism is the user-name and password pair, which provides a single point of failure. By increasing the factors used in authentication, the amount of work required to compromise the system increases non-linearly. Within an open network, several aspects hinder wide scale adoption and use of multi-factor authentication schemes, such as token management and the impact on usability. The framework is developed from a Utopian point of view, with the aim of being applicable to many situations as opposed to a single specific domain. The framework incorporates multi-factor authentication over multiple paths using mobile phones and GSM networks, and explores the usefulness of such an approach. The models are in tum analysed, providing a discussion into the assumptions made and the problems faced by each model.Adobe Acrobat Pro 9.5.1Adobe Acrobat 9.51 Paper Capture Plug-i

Problems in Cloud Security, Access Control and Logic Locking

In this thesis, we study problems related to security in three different contexts: cloud scheduling, access control, and logic locking to protect digital ICs. The first set of problems relates to security in cloud computing. Prior work suggests that scheduling, with security as a consideration, can be effective in minimizing information leakage, via side-channels, that can exist when virtual machines (VMs) co-reside in clouds. We analyze the overhead that is incurred by such an approach. We first pose and answer a fundamental question: is the problem tractable? We show that the seemingly simpler sub-cases of initial placement and migration across only two equal-capacity servers are both intractable (NP-hard). However, a decision version of the general problem to which the optimization version is related polynomially is in NP. With these results as the basis, we make several other contributions. We revisit recent work that proposes a greedy algorithm for this problem, called Nomad. We establish that if P != NP, then there exist infinitely many classes of input, each with an infinite number of inputs, for which a decrease in information leakage is possible, but Nomad provides none, let alone minimize it. We establish also that a mapping to Integer Linear Programming (ILP) in prior work is deficient in that the mapping can be inefficient (exponential-time), and therefore does not accurately convey the overhead of such an approach that actually decreases information leakage. We present our efficient reductions to ILP and boolean satisfiability in conjunctive normal form (CNF-SAT). We have implemented these approaches and conducted an empirical assessment using the same ILP solver as prior work, and a SAT solver. Our analytical and empirical results more accurately convey the overhead that is incurred by an approach that actually provides security (decrease in information leakage). The second set of problems relates to access control. We pose and study forensic analysis in the context of access control systems. Forensics seeks to answer questions about past states of a system, and thereby provides important clues and evidence in the event of a security incident. Access control deals with who may perform what action on a resource and is an important security function. We argue that access control is an important context in which to consider forensic analysis, and observe that it is a natural complement of safety analysis, which has been considered extensively in the literature. We pose the forensic analysis problem for access control systems abstractly, and instantiate it for three schemes from the literature: a well-known access matrix scheme, a role-based scheme, and a discretionary scheme. In particular, we ask what the computational complexity of forensic analysis is, and compare it to the computational complexity of safety analysis for each of these schemes. We observe that in the worst-case, forensic analysis lies in the same complexity class as safety analysis. We consider also the notion of logs, i.e., data that can be collected over time to aid forensic analysis. We present results for sufficient and minimal logs that render forensic analysis for the three schemes efficient. This motivates discussions on goal-directed logging, with the explicit intent of aiding forensic analysis. We carry out a case-study in the realistic setting of a serverless cloud application, and observe that goal-directed logging can be highly effective. Our work makes contributions at the foundations of information security, and its practical implications. The third set of problems relates to logic locking to protect digital integrated circuits (ICs) against untrusted semiconductor foundries. We make two sets of complementary contributions, all rooted in foundations and bolstered by implementations and empirical results. Our first set of contributions regards observations about prior schemes and attacks, and our second is a new security notion. Towards the former, we make two contributions. (a) We revisit a prior approach called XOR-locking that has been demonstrated to be susceptible, in practice, to a particular attack called the SAT attack. We establish that (i) there exist circuits that are invulnerable to the SAT attack when XOR-locked with even a 1-bit key, and, (ii) there is a particular property that is inherent to benchmark circuits that explains why the SAT attack is successful against XOR-locked versions of those. Both (i) and (ii) are rooted in computing foundations: for (i), one-way functions; for (ii), average-case computational complexity, specifically, the class distP. (b) We revisit a state-of-art logic locking approach called TTLock whose generalization called SFLL-HD has been argued to be ``provably secure'' in prior work. We devise a new, probabilistic attack against TTLock. We explain, from foundations, why benchmark circuits that are locked using TTLock are susceptible to our new attack. Our observations (a) and (b), and prior work on attacks, informs our second contribution, which is a new security notion. Our notion is at least as strong as the property that underlies the SAT attack