32 research outputs found

    On the automatic construction of indistinguishable operations

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    An increasingly important design constraint for software running on ubiquitous computing devices is security, particularly against physical methods such as side-channel attack. One well studied methodology for defending against such attacks is the concept of indistinguishable functions which leak no information about program control flow since all execution paths are computationally identical. However, constructing such functions by hand becomes laborious and error prone as their complexity increases. We investigate techniques for automating this process and find that effective solutions can be constructed with only minor amounts of computational effort.Fundação para a Ciência e Tecnologia - SFRH/BPD/20528/2004

    Nε-lysine acetylation of the histone-like protein HBsu influences antibiotic survival and persistence in Bacillus subtilis

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    Nε-lysine acetylation is recognized as a prevalent post-translational modification (PTM) that regulates proteins across all three domains of life. In Bacillus subtilis, the histone-like protein HBsu is acetylated at seven sites, which regulates DNA compaction and the process of sporulation. In Mycobacteria, DNA compaction is a survival strategy in response antibiotic exposure. Acetylation of the HBsu ortholog HupB decondenses the chromosome to escape this drug-induced, non-growing state, and in addition, regulates the formation of drug-tolerant subpopulations by altering gene expression. We hypothesized that the acetylation of HBsu plays similar regulatory roles. First, we measured nucleoid area by fluorescence microscopy and in agreement, we found that wild-type cells compacted their nucleoids upon kanamycin exposure, but not exposure to tetracycline. We analyzed a collection of HBsu mutants that contain lysine substitutions that mimic the acetylated (glutamine) or unacetylated (arginine) forms of the protein. Our findings indicate that some level of acetylation is required at K3 for a proper response and K75 must be deacetylated. Next, we performed time-kill assays of wild-type and mutant strains in the presence of different antibiotics and found that interfering with HBsu acetylation led to faster killing rates. Finally, we examined the persistent subpopulation and found that altering the acetylation status of HBsu led to an increase in persister cell formation. In addition, we found that most of the deacetylation-mimic mutants, which have compacted nucleoids, were delayed in resuming growth following removal of the antibiotic, suggesting that acetylation is required to escape the persistent state. Together, this data adds an additional regulatory role for HBsu acetylation and further supports the existence of a histone-like code in bacteria

    Does Coupling Affect the Security of Masked Implementations?

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    Masking schemes achieve provable security against side-channel analysis by using secret sharing to decorrelate key-dependent intermediate values of the cryptographic algorithm and side-channel information. Masking schemes make assumptions on how the underlying leakage mechanisms of hardware or software behave to account for various physical effects. In this paper, we investigate the effect of the physical placement on the security using leakage assessment on power measurements collected from an FPGA. In order to differentiate other masking failures, we use threshold implementations as masking scheme in conjunction with a high-entropy pseudorandom number generator. We show that we can observe differences in---possibly---exploitable leakage by placing functions corresponding to different shares of a cryptographic implementation in close proximity

    Secure and Efficient AES Software Implementation for Smart Cards

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    In implementing cryptographic algorithms on limited devices such as smart cards, speed and memory optimization had always been a challenge

    Can traditional organizations be digitally transformed by themselves? The moderating role of absorptive capacity and strategic interdependence

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    Although digital transformation has significantly attracted scholarly attention beyond information systems, little is known whether traditional organizations can be digitally transformed alone. Knowledge of this process is important as traditional organizations risk failing to achieve digital transformation due to their lack of understanding about digitalization. This research proposes a conceptual framework, which approaches the digital transformation of traditional organizations as a coordinated sequence of specific relationships. The research propositions first outline the relationship between alliance knowledge and digital transformation as a necessary but not absolute condition for the digitalization of traditional conditions. Effectively, therefore, the constructs of absorptive capacity and strategic interdependence are considered to be boundary conditions to this relationship. Insights are also provided into traditional organizations’ levels of absorptive capacity (high vs. low) as well as into the levels of interdependence between them and their partners (symmetry vs. asymmetry), which both determine the outcomes of digital transformation. Concurring with these propositions, this framework advances our understanding of why traditional organizations struggle to be digitally transformed alone and provides implications for both theory and practice. © 202

    Parallel Program Design in Visual Environment

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    The great challenge in parallel computing is to make a task of programming parallel machines easy while not sacrificing the efficiency of target code. One of the successful methodologies is to start from a high-level specification of the functional behaviour of a program by applying a sequence of optimising transformations tuned for a particular architecture to generate a specification of the operational behaviour of a parallel program. We believe that visualisation is an excellent way to bring this methodology to a wider programming community. In this paper we describe an interactive visual system which integrates 3D graphics, animation, and direct manipulation techniques into parallel programming environment. Keywords: parallel program development, algorithm analysis, data dependency graph, domain morphisms, visualisation. 1 Introduction Parallel program design and analysis is a complex activity, where many difficulties stem from the principle inadequacy of pure textual formalism ..

    Market knowledge acquisition and transfer in international SMEs: peculiarities, specifications and linkages to market success

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    Purpose: This paper aims to systematically review and evaluate extant literature on knowledge acquisition and transfer in international small-to-medium enterprises (SMEs) and to identify the requisite types of knowledge acquired and transferred in this context. The research further determines the mechanisms enabling SMEs to process this knowledge, unpacks the benefits of both knowledge acquisition and transfer for international SMEs and links them to the market success. Design/methodology/approach: The research has conducted a comprehensive systematic review of existing literature on market knowledge acquisition and its transfer, in the context of international SMEs, utilizing peer-reviewed articles published in top tier journals without any custom range of time. Findings: The search strategy resulted in 37 reviewed academic articles, whose analysis identifies and elucidates on the best practices of knowledge acquisition and transfer in the context of international SMEs; the type of the knowledge acquired and transferred; the form and mechanism of the intersection of these processes; and the benefits gained. The findings, crucially, also identify and illuminate extant research gaps and insufficiencies and develop a comprehensive research agenda for the way forward. Originality/value: The present study offers a uniquely comprehensive perspective on a topic of diachronic and, currently, rising significance to scholars and practitioners alike. Transcending its descriptive value, though, it further identifies extant knowledge deficiencies, it distils and consolidates critical knowledge and prescribes avenues for research towards the growth and development of international SMEs and born globals. © 2021, Emerald Publishing Limited
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