6 resultados para Predicate encryption

em Universidade Federal do Rio Grande do Norte(UFRN)


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RFID (Radio Frequency Identification) identifies object by using the radio frequency which is a non-contact automatic identification technique. This technology has shown its powerful practical value and potential in the field of manufacturing, retailing, logistics and hospital automation. Unfortunately, the key problem that impacts the application of RFID system is the security of the information. Recently, researchers have demonstrated solutions to security threats in RFID technology. Among these solutions are several key management protocols. This master dissertations presents a performance evaluation of Neural Cryptography and Diffie-Hellman protocols in RFID systems. For this, we measure the processing time inherent in these protocols. The tests was developed on FPGA (Field-Programmable Gate Array) platform with Nios IIr embedded processor. The research methodology is based on the aggregation of knowledge to development of new RFID systems through a comparative analysis between these two protocols. The main contributions of this work are: performance evaluation of protocols (Diffie-Hellman encryption and Neural) on embedded platform and a survey on RFID security threats. According to the results the Diffie-Hellman key agreement protocol is more suitable for RFID systems

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Wireless sensors and actuators Networks specified by IEEE 802.15.4, are becoming increasingly being applied to instrumentation, as in instrumentation of oil wells with completion Plunger Lift type. Due to specific characteristics of the environment being installed, it s find the risk of compromising network security, and presenting several attack scenarios and the potential damage from them. It`s found the need for a more detailed security study of these networks, which calls for use of encryption algorithms, like AES-128 bits and RC6. So then it was implement the algorithms RC6 and AES-128, in an 8 bits microcontroller, and study its performance characteristics, critical for embedded applications. From these results it was developed a Hybrid Algorithm Cryptographic, ACH, which showed intermediate characteristics between the AES and RC6, more appropriate for use in applications with limitations of power consumption and memory. Also was present a comparative study of quality of security among the three algorithms, proving ACH cryptographic capability.

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Based on studies on the structure of copulates sentences in Brazilian Portuguese (PB), according to grammar theory, it s analyzed on this dissertation, the complex copulate sentences what, in the PB, initiated by the formation é ruim que in the PB, bringing the hypothesis that they can have one predicacional reading (PRED) and other especificacional reading (ESP). It s revealed what, though they are similar slightly, that makes the different that are triggered is structural configuration of sentence and the form as come emerged the its constituents: that of PRED interpretation, that we defined as Common Copulate Sentence (or SCC), it s checked that the constituent ruim, and only it, is predicate of a Small Clause, and appears in the structure on even position wherein is pronounced, not passing by the method of movement, from where introduce wide predication on all subject, that is the CP built-in; those sentences é ruim que understanding ESP, that denominate of Negative Copulate Sentence (or SCN), whereas the fixed expression contradict or right what is asserted in built-in, it s perceived what the ruim is a part of this fixed expression, and surely crystallized, which appears in structure per movement, germinated as adjunct of Inflexional Phrase (IP) and being elevation to specifier to FocP (or SpecFocP), where acquires discursive interpretation of focus. Besides the mode as the ruim or the fixed expression emerge in that sentences, the relation between the copula and main verb likewise contribute to distinguish the sentences: 1) regarding flexion of mode, when is a SCC, the copula must be in the mode indicative, and the main verb, in the subjunctive; when is a SCN, copula and main verb must be always on indicative; 2) regarding flexion of temp, both the copula as main verb of the SCC can be flexed, whereas at the SCN, the main verb can vary in present, past and future, but the copula should appear, necessarily, in third persona of present of indicative, what confirms our hypothesis that there is an fixed expression at the copulate sentences with é ruim que ESP. Other two evidences are pointed as characteristics that distinguish the sentence with é ruim que PRED of sentence with é ruim que ESP: 1) in semantics, the constituent ruim equals not good, that has appreciation, when the reading will PRED; already the pair é ruim equals not, at the ESP; 2) in prosody, there discrete sound elevation the ruim on the other constituents of SCC, PRED, while there is accentuated acoustic elevation on the ruim of SCN, ESP. Our search it is grounded in authors as Zanfeliz (2000), Modesto (2001), Mioto (2003), Kato & Ribeiro (2006), Lobo (2006), Quarezemin (2006, 2009, 2011, 2012) e Resenes (2009), researchers that devoted their attention on studies the formation and organization of the constituents of cleaved sentences and focalization of constituent, basing itself in approach generative of linguistic

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This work analyzes deverbal nominalizations with the sufix dor in Brazilian Portuguese, under the perspective of Cognitive Linguistics, more specifically, the Construction Grammar. The aim is to determine the general features of interpretation that characterize this deverbal construction and its use in formal writing. Based on the cognitive assumption that grammatical structure is motivated, explained, and determined by the structure of cognitive patterns, created from our experience in the world, and by the communicative function of language, the dor deverbal is treated as a polysemic grammatical construction. In the composition of V+dor, the relation rootsuffix is focused, through a characterization of the syntactic-semantic nature of the verb and the values of the suffix. Among the different values conventionally related to the XDOR construction, the agentive is considered as the prototypical sense. The relation between the other values and the prototype is explained by cognitive abilities and discourse motivations. The deverbal construction X-DOR is also interpreted as a valency noun that, like an action nominal, retains the argument structure of the deriving predicate. It is also intended to demonstrate the textual function of this deverbal construction, as a device of information condensing and anaphoric recovery. The data were taken from Veja magazine and the approach is qualitative (explicative), with quantitative support

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Web services are loosely coupled applications that use XML documents as a way of integrating distinct systems on the internet. Such documents are used by in standards such as SOAP, WSDL and UDDI which establish, respectively, integrated patterns for the representation of messages, description, and publication of services, thus facilitating the interoperability between heterogeneous systems. Often one single service does not meet the users needs, therefore new systems can be designed from the composition of two or more services. This which is the design goal behind the of the Service Oriented Architecture. Parallel to this scenario, we have the PEWS (Predicate Path-Expressions for Web Services) language, which speci es behavioural speci cations of composite web service interfaces.. The development of the PEWS language is divided into two parts: front-end and back-end. From a PEWS program, the front-end performs the lexical analysis, syntactic and semantic compositions and nally generate XML code. The function of the back-end is to execute the composition PEWS. This master's dissertation work aims to: (i) reformulate the proposed architecture for the runtime system of the language, (ii) Implement the back-end for PEWS by using .NET Framework tools to execute PEWS programs using the Windows Work ow Foundation

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There are authentication models which use passwords, keys, personal identifiers (cards, tags etc) to authenticate a particular user in the authentication/identification process. However, there are other systems that can use biometric data, such as signature, fingerprint, voice, etc., to authenticate an individual in a system. In another hand, the storage of biometric can bring some risks such as consistency and protection problems for these data. According to this problem, it is necessary to protect these biometric databases to ensure the integrity and reliability of the system. In this case, there are models for security/authentication biometric identification, for example, models and Fuzzy Vault and Fuzzy Commitment systems. Currently, these models are mostly used in the cases for protection of biometric data, but they have fragile elements in the protection process. Therefore, increasing the level of security of these methods through changes in the structure, or even by inserting new layers of protection is one of the goals of this thesis. In other words, this work proposes the simultaneous use of encryption (Encryption Algorithm Papilio) with protection models templates (Fuzzy Vault and Fuzzy Commitment) in identification systems based on biometric. The objective of this work is to improve two aspects in Biometric systems: safety and accuracy. Furthermore, it is necessary to maintain a reasonable level of efficiency of this data through the use of more elaborate classification structures, known as committees. Therefore, we intend to propose a model of a safer biometric identification systems for identification.