Non-invasive Techniques Towards Recovering Highly Secure Unclonable Cryptographic Keys and Detecting Counterfeit Memory Chips

Due to the ubiquitous presence of memory components in all electronic computing systems, memory-based signatures are considered low-cost alternatives to generate unique device identifiers (IDs) and cryptographic keys. On the one hand, this unique device ID can potentially be used to identify major types of device counterfeitings such as remarked, overproduced, and cloned. On the other hand, memory-based cryptographic keys are commercially used in many cryptographic applications such as securing software IP, encrypting key vault, anchoring device root of trust, and device authentication for could services. As memory components generate this signature in runtime rather than storing them in memory, an attacker cannot clone/copy the signature and reuse them in malicious activity. However, to ensure the desired level of security, signatures generated from two different memory chips should be completely random and uncorrelated from each other. Traditionally, memory-based signatures are considered unique and uncorrelated due to the random variation in the manufacturing process. Unfortunately, in previous studies, many deterministic components of the manufacturing process, such as memory architecture, layout, systematic process variation, device package, are ignored. This dissertation shows that these deterministic factors can significantly correlate two memory signatures if those two memory chips share the same manufacturing resources (i.e., manufacturing facility, specification set, design file, etc.). We demonstrate that this signature correlation can be used to detect major counterfeit types in a non-invasive and low-cost manner. Furthermore, we use this signature correlation as side-channel information to attack memory-based cryptographic keys. We validate our contribution by collecting data from several commercially available off-the-shelf (COTS) memory chips/modules and considering different usage-case scenarios

Reducing the Cost of Operating a Datacenter Network

Datacenters are a significant capital expense for many enterprises. Yet, they are difficult to manage and are hard to design and maintain. The initial design of a datacenter network tends to follow vendor guidelines, but subsequent upgrades and expansions to it are mostly ad hoc, with equipment being upgraded piecemeal after its amortization period runs out and equipment acquisition is tied to budget cycles rather than changes in workload. These networks are also brittle and inflexible. They tend to be manually managed, and cannot perform dynamic traffic engineering. The high-level goal of this dissertation is to reduce the total cost of owning a datacenter by improving its network. To achieve this, we make the following contributions. First, we develop an automated, theoretically well-founded approach to planning cost-effective datacenter upgrades and expansions. Second, we propose a scalable traffic management framework for datacenter networks. Together, we show that these contributions can significantly reduce the cost of operating a datacenter network. To design cost-effective network topologies, especially as the network expands over time, updated equipment must coexist with legacy equipment, which makes the network heterogeneous. However, heterogeneous high-performance network designs are not well understood. Our first step, therefore, is to develop the theory of heterogeneous Clos topologies. Using our theory, we propose an optimization framework, called LEGUP, which designs a heterogeneous Clos network to implement in a new or legacy datacenter. Although effective, LEGUP imposes a certain amount of structure on the network. To deal with situations when this is infeasible, our second contribution is a framework, called REWIRE, which using optimization to design unstructured DCN topologies. Our results indicate that these unstructured topologies have up to 100-500\% more bisection bandwidth than a fat-tree for the same dollar cost. Our third contribution is two frameworks for datacenter network traffic engineering. Because of the multiplicity of end-to-end paths in DCN fabrics, such as Clos networks and the topologies designed by REWIRE, careful traffic engineering is needed to maximize throughput. This requires timely detection of elephant flows---flows that carry large amount of data---and management of those flows. Previously proposed approaches incur high monitoring overheads, consume significant switch resources, or have long detection times. We make two proposals for elephant flow detection. First, in the Mahout framework, we suggest that such flows be detected by observing the end hosts' socket buffers, which provide efficient visibility of flow behavior. Second, in the DevoFlow framework, we add efficient stats-collection mechanisms to network switches. Using simulations and experiments, we show that these frameworks reduce traffic engineering overheads by at least an order of magnitude while still providing near-optimal performance

Towards Topology-Hiding Computation from Oblivious Transfer

Topology-Hiding Computation (THC) enables parties to securely compute a function on an incomplete network without revealing the network topology. It is known that secure computation on a complete network can be based on oblivious transfer (OT), even if a majority of the participating parties are corrupt. In contrast, THC in the dishonest majority setting is only known from assumptions that imply (additively) homomorphic encryption, such as Quadratic Residuosity, Decisional Diffie-Hellman, or Learning With Errors. In this work we move towards closing the gap between MPC and THC by presenting a protocol for THC on general graphs secure against all-but-one semi-honest corruptions from constant-round constant-overhead secure two-party computation. Our protocol is therefore the first to achieve THC on arbitrary networks without relying on assumptions with rich algebraic structure. As a technical tool, we introduce the notion of locally simulatable MPC, which we believe to be of independent interest

Use of a pseudotyped retoviral vector to accomplish insertional mutagenesis in zebrafish

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 1998.Includes bibliographical references.by Adam Amsterdam.Ph.D

Affinity maturation and characterization of novel binders to the HIV-1 TAR element based on the U1A RNA recognition motif

2018 Fall.Includes bibliographical references.The increased understanding of the importance of RNA, both as a carrier of information and as a functional molecule, has led to a greater demand for the ability to target specific RNAs, but the limited chemical diversity of RNA makes this challenging. This thesis documents the use of yeast display to perform affinity maturation for the ability of a protein to bind the TAR element of HIV-1, which is a desirable therapeutic target due to its prominent role in the HIV-1 infection cycle. To accomplish this, we used a "semi-design" strategy—repurposing a natural RNA bind- ing protein to bind a different target—by creating a library based on important binding regions (especially the β2β3 loop) of the U1A RRM. Following selection for TAR binding, a strong consensus sequence in the β2β3 loop emerged. The affinity of certain library members for TAR was measured by ELISA and SPR, and it was determined that the best binder (TBP 6.7) had remarkable affinity (KD = ~500 pM). This TAR binding protein also proved capable of disrupting the Tat–TAR interaction (necessary for HIV-1 replication) both in vitro and in the context of extracellular transcription. Through collaboration, we were able to obtain a co-crystal structure of TBP 6.7 and TAR. This crystal structure showed that the overall structure of TBP 6.7 was largely unchanged from that of U1A, thereby validating our semi-design strategy. We also found that the β2β3 loop played a disproportionately large role in the binding interaction (~2⁄3 of the buried surface area). The importance of this region inspired the creation and characterization of peptide derivatives of the TBP 6.7 β2β3 loop. These β2β3 loop derived peptides maintain affinity for TAR RNA (KD = ~1.8 μM), and can disrupt Tat/TAR-dependent transcription. Ultimately, the project has yielded the most avid known binders of TAR RNA, a potential novel platform of TAR binding peptides, and a crystal structure which will hopefully inform future targeting efforts

A global strategy for the conservation and use of coconut genetic resources 2018-2028

This strategy came from extensive worldwide consultations, with support from Bioversity International, CIRAD, CRFP-FTA and ACIAR/DFAT, and outlines the means to conserve / use as much representative diversity as possible. More than 100 million people living in fragile coastal areas depend on coconut for their livelihoods. Globally, the demand for coconut products is expanding and offers new opportunities for increasing incomes for millions of small-scale coconut producers…. At a time when the demand for coconut and coconut products is growing worldwide, it is important to conserve and utilize the rich biological diversity of the crop. This evolving Strategy will provide the benchmark for effectively implementing the comprehensive conservation and research agenda proposed by the international coconut research community, as a route to the enhanced wellbeing of millions of coconut smallholders across the globe

A global strategy for the conservation and use of coconut genetic resources, 2018-2028

This strategy came from extensive worldwide consultations, with support from Bioversity International, CIRAD, CRFP-FTA and ACIAR/DFAT, and outlines the means to conserve / use as much representative diversity as possible. More than 100 million people living in fragile coastal areas depend on coconut for their livelihoods. Globally, the demand for coconut products is expanding and offers new opportunities for increasing incomes for millions of small-scale coconut producers... At a time when the demand for coconut and coconut products is growing worldwide, it is important to conserve and utilize the rich biological diversity of the crop. This evolving Strategy will provide the benchmark for effectively implementing the comprehensive conservation and research agenda proposed by the international coconut research community, as a route to the enhanced wellbeing of millions of coconut smallholders across the globe