606 research outputs found

    HardIDX: Practical and Secure Index with SGX

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    Software-based approaches for search over encrypted data are still either challenged by lack of proper, low-leakage encryption or slow performance. Existing hardware-based approaches do not scale well due to hardware limitations and software designs that are not specifically tailored to the hardware architecture, and are rarely well analyzed for their security (e.g., the impact of side channels). Additionally, existing hardware-based solutions often have a large code footprint in the trusted environment susceptible to software compromises. In this paper we present HardIDX: a hardware-based approach, leveraging Intel's SGX, for search over encrypted data. It implements only the security critical core, i.e., the search functionality, in the trusted environment and resorts to untrusted software for the remainder. HardIDX is deployable as a highly performant encrypted database index: it is logarithmic in the size of the index and searches are performed within a few milliseconds rather than seconds. We formally model and prove the security of our scheme showing that its leakage is equivalent to the best known searchable encryption schemes. Our implementation has a very small code and memory footprint yet still scales to virtually unlimited search index sizes, i.e., size is limited only by the general - non-secure - hardware resources

    Pholidosis Abnormalities and Injuries in the European Pond Turtle (Emys orbicularis) in the Conditions of the Khopersky Nature Reserve

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    Pholidosis abnormalities and injuries were studied through 194 specimens of European pond turtle (Emys orbicularis) in the Khopersky nature reserve (Voronezh Province, Russia) in 2008, 2009 and 2011. Six types of abnormalities (on the carapace only) were detected. The occurrence of individuals with all types of abnormalities, the partial occurrence of various abnormalities and the average number of abnormalities per individual were analyzed. Most individuals showed signs of predator attack, mostly on the carapace and tail. During winter hibernation, animals with limb injuries were noted

    On Notions of Security for Deterministic Encryption, and Efficient Constructions Without Random Oracles

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    The study of deterministic public-key encryption was initiated by Bellare et al. (CRYPTO ’07), who provided the “strongest possible” notion of security for this primitive (called PRIV) and constructions in the random oracle (RO) model. We focus on constructing efficient deterministic encryption schemes without random oracles. To do so, we propose a slightly weaker notion of security, saying that no partial information about encrypted messages should be leaked as long as each message is a-priori hard-to-guess given the others (while PRIV did not have the latter restriction). Nevertheless, we argue that this version seems adequate for many practical applications. We show equivalence of this definition to single-message and indistinguishability-based ones, which are easier to work with. Then we give general constructions of both chosen-plaintext (CPA) and chosen-ciphertext-attack (CCA) secure deterministic encryption schemes, as well as efficient instantiations of them under standard number-theoretic assumptions. Our constructions build on the recently-introduced framework of Peikert and Waters (STOC ’08) for constructing CCA-secure probabilistic encryption schemes, extending it to the deterministic-encryption setting as well

    Order-Revealing Encryption: File-Injection Attack and Forward Security

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    Order-preserving encryption (OPE) and order-revealing encryption (ORE) are among the core ingredients for encrypted database (EDB) systems as secure cloud storage. In this work, we study the leakage of OPE and ORE and their forward security. We propose generic yet powerful file-injection attacks (FIAs) on OPE/ORE, aimed at the situations of possessing order by and range queries. The FIA schemes only exploit the ideal leakage of OPE/ORE (in particular, no need of data denseness or frequency). We also improve its efficiency with the frequency statistics using a hierarchical idea such that the high-frequency values will be recovered more quickly. Compared with other attacks against OPE/ORE proposed in recent years, our FIA attacks rely upon less demanding conditions and are more effective for attacking the systems with the function of data sharing or transferring like encrypted email system. We executed some experiments on real datasets to test the performance, and the results show that our FIA attacks can cause an extreme hazard on most of the existing OPE and ORE schemes with high efficiency and 100% recovery rate. In order to resist the perniciousness of FIA, we propose a practical compilation framework for achieving forward secure ORE. The compilation framework only uses some simple cryptographical tools like pseudo-random function, hash function and trapdoor permutation. It can transform most of the existing OPE/ORE schemes into forward secure ORE schemes, with the goal of minimizing the extra burden incurred on computation and storage. We also present its security proof and execute some experiments to analyze its performance

    History of International Relations of Cities of Arkhangelsk Region in 1990s — 2010s: Transition from Social-Humanitarian to Trade-Economic Cooperation

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    The article discusses the development of international sister city relations in the 1990s — 2010s using the example of the Arkhangelsk region. The authors provide an overview of existing approaches in historiography to analyzing municipal-level international partnership relations in different regions of Russia and the world. Based on a wide range of sources, including international agreements, federal and regional regulatory acts, and reporting documentation over the past 30 years, the article pays particular attention to the region’s attempts in the 2000s — 2010s to move from exclusively social-humanitarian cooperation to developing economic ties with partner cities and regions. The real impact of sister city relations on the development of external economic ties in the region is analyzed in detail, as well as changes in the share of countries with which partner relations were established in the overall external trade turnover of the Arkhangelsk region. The authors conclude that there is currently no state regulation of the institution of sister city relations at the federal and regional levels. Such a situation creates serious difficulties for further development of this institution of public diplomacy, expanding the external economic activities of Russian regions, and spreading Russia’s “soft power” in the world

    Electroencephalographic Intercentral Interaction as a Reflection of Normal and Pathological Human Brain Activity

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    The authors summarized EEG findings and defined the nature of the intercentral EEG relationships in different functional states in healthy subjects and patients with organic cerebral pathology, based on a coherence analysis. Similar EEG characteristics in healthy individuals were identified: an anterior-posterior gradient of average coherence levels, the type of cortical-subcortical relationships in anterior cerebral structures. Right- and left-handed individuals showed frequent and regional differences in EEG coherence, which mainly reflected specificity of intracortical relationships. Development and regression of pathology in right-and left-handed individuals with organic brain lesions were thought to be caused by these differences. Lesions of regulatory structures (diencephalic, brain stem and limbic structures) provoked a more diffused kind of changes of intercentral relationships, in contrast to cortical pathology. These changes tended to reciprocate. The dynamic nature of intercentral relationships and their interhemispheric differences was revealed when changing functional states of the brain (increase and decrease of functional level) in healthy individuals and patients with organic cerebral pathology in the process of conscious and psychic activity restoration. Changing activity predominance of certain regulatory structures was considered one of the most important factors determining the dynamic nature of EEG coherenceLos autores resumen los resultados de las investigaciones de las relaciones intercentrales de EEG de personas sanas en distintos estados funcionales y de enfermos con lesiones orgánicas del SNC, mediante análisis de coherencia. Se revelan características semejantes de la estructura de relaciones de EEG de personas sanas: la gradiente anterior-posterior de niveles medios de coherencia, el carácter de la interacción cortical-subcortical de las secciones anteriores de los hemisferios. A su vez, se detectan diferencias de frecuencia y regionales en la coherencia de EEG en diestros y zurdos, que reflejan mayoritariamente la especificidad de la interacción intracortical. Se cree que estas diferencias causan la especificidad del desarrollo y la regresión de los estados patológicos de diestros y zurdos en lesiones cerebrales orgánicas. Se señala que en las lesiones de formaciones reguladoras (diencefálicas, troncales, límbicas) Provocan unos cambios de las relaciones intercentrales más difusos que en casos de patología cortical. Estos cambios tienden a la reciprocidad. Se revela el carácter dinámico de las relaciones intercentrales y sus diferencias interhemisféricas en los cambios de los estados funcionales del cerebro (incremento, disminución del nivel de funcionamiento) en personas sanas así como en la recuperación de la conciencia y la actividad psíquica en enfermos con patología cerebral orgánica. Uno de los factores que determina el carácter dinámico del cambio de la coherencia del EEG es el cambio del predominio de la actividad de ciertas estructuras reguladoras

    Ensuring Data Storage Security against Frequency-Based Attacks in Wireless Networks

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