The **RSA** algorithm [1] is a public key algorithm and is extensively in security and authentication applications. Being computationally intensive, use **of** separate crypto-accelerator hardware to accelerate the computations is common. The communication between the main processor (32-64 bit) and the **RSA** crypto-accelerator (1024-2048 bit) requires a protocol for data exchange and a FIFO register bank can implemented for the same. This paper describes an **architecture** design for the **RSA** **cryptosystem** useful for both the Encryption/Decryption and for the Key-Pair Generation which may be required due to security. The number to be tested as prime is fed as input to the system and the random numbers for Miller-Rabin test are generated using Pseudo-Random Number Generator (PRNG).

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We propose an **efficient** hardware **architecture** design & implementation **of** Advanced Encryption Standard (AES)-Rijndael **cryptosystem**. The AES algorithm defined by the National Institute **of** Standard and Technology (NIST) **of** United States has been widely accepted. The cryptographic algorithms can be implemented with software or built with pure hardware. However Field Programmable Gate Arrays (FPGA) implementation offers quicker solution and can be easily upgraded to incorporate any protocol changes. This contribution investigates the AES encryption and decryption **cryptosystem** with regard to FPGA and Very High Speed Integrated Circuit Hardware Description language (VHDL). Optimized and Synthesizable VHDL code is developed for the implementation **of** both 128- bit data encryption and decryption process. Xilinx ISE 8.1 software is used for simulation. Each program is tested with some **of** the sample vectors provided by NIST and output results are perfect with minimal delay. The throughput reaches the value **of** 352 Mbit/sec for both encryption and decryption process with Device XCV600 **of** Xilinx Virtex Family.

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Abstract—**ASIC** implementation **of** a parallel binary comparator based on radix-2 tree structure, utilizing Carry Look Ahead (CLA) technique is proposed in this brief. This novel comparator **architecture** achieves both low power and high-speed operation, particularly at low-input data activity environments. The proposed comparator is designed using VHDL code and synthesized using ALTERA QUARTUS - II. Experimental evaluation **of** the proposed and state **of**-the-art designs revealed that the proposed comparator design exhibits a reduction in delay by 49.8% and gate count by 42.6% for a 16 bit design, compared to the best **of** the schemes used for comparison.

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2 the problem **of** solving nonlinear system **of** equations over finite fields which is proven to be NP-complete. Quantum computers do not seem to have any advantage on solving NP-complete problems, so multivariate cryptography can be a viable option applicable to both conventional and quantum computers. MIC*, the first practical public key **cryptosystem** based on this problem was proposed in 1988 [5] by T. Matsumoto and H. Imai. The MIC* **cryptosystem** was based on the idea **of** hiding a monomial by two invertible affine transformations. This **cryptosystem** was more **efficient** than **RSA** and ECC. Unfortunately this **cryptosystem** was broken by Patarin in 1995[6]. In 1996 [7] Patarin gave a generalisation **of** MIC* **cryptosystem** called HFE, however in HFE the secret key computation was not as **efficient** as in the original MIC* **Cryptosystem**. The basic instance **of** HFE was broken in 1999[9]. The attack uses a simple fact that every homogeneous quadratic multivariate polynomial has a matrix representation. Using this representation a highly over defined system **of** equations can be obtained which can be solved by a new technique called relinearization [9]. Patarin [8] investigated whether it is possible to repair MIC* with the same kind **of** easy secret key computations. He designed some cryptosystems known as Little Dragon and Big Dragon with multivariate polynomials **of** total degree 2 and 3 respectively in plaintext and cipher text variables in public key with efficiency comparable to MIC*. Due to its efficiency and quadratic public key size, the Little Dragon Scheme was more interesting, however Patarin found [8], [3] that Little Dragon Scheme is insecure. Some more multivariate public key cryptosystems can be found in reference [11] and [12]. For a brief introduction **of** multivariate cryptography we refer to the interested readers to reference [13]. An interesting introduction **of** hidden monomial cryptosystems can be found in reference [3].

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The **RSA** **cryptosystem** is the “de-facto” standard for Public-key encryption and signature worldwide. We survey, present, and analyze the most common against **RSA** attacks. Integer factoring methods, attacks on the underlying mathematical function, as well as attacks the exploit details in implementations **of** the algorithm are presented. It was shown that no attack algorithm can break **RSA** **cryptosystem** in **efficient** manner. Most attacks appear to be result **of** misuse **of** the system or bad choice **of** parameters. Analysis **of** the known attacks shows that **RSA** has not been proven to be unbreakable, but having survived a great deal **of** cryptanalytic security over the last twenty years.

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were performed on the well known images: Lena, Airplane, Peppers, Boat, Gold hill and Couple. These 6 test grey-images have a size **of** 512×512 and resolution **of** 8-bits. For our experiment, we first corrupt these images by impulse noise, for example, salt-and-pepper noise. The “salt” and “pepper” noise are assumed to be equi-probable. Noise is included artificially to the original image using the MATLAB command “imnoise”. The impulse noise used in our simulations are random valued and is equally spread over a range which is between [0, 255]. A window **of** size 9×9 has been adopted throughout the experiment.

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One **of** the major disadvantages **of** using an FPGA lies the interconnectivity fabric as pro- grammable switches are used. In contrary, a standard cell-based circuit is interconnected with metal wires. Interconnectivity relied on switches poses a problem, as switches have a higher re- sistance than metal wires adding significant capacitance, reducing the maximum able frequency on an FPGA. FPGA switches also take more space than metal wires, increasing the overall circuit size compared to an **ASIC** implementation. As compelling as an FPGA solution may seem, an FPGA solution sees an area increase **of** around 40 times, plus four times decrease on circuit speed, and ten times more power consumption [6]. This values shall be carefully analyzed by a designer so that the best device is chosen for the intended application.

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A criptografia é a ciência incumbida em estudar os métodos para codificar uma mensagem de forma que só o destinatário legítimo consiga interpretá-la. “É a arte dos códigos secretos”. Esta arte se apresenta já na infância quando se brinca de substituir uma letra por outra, transladando o alfabeto uma casa para diante. A criptografia é estudada desde a antiguidade, sendo que durante os séculos seguintes foram desen- volvidos diversos sistemas criptográficos mais ou menos engenhosos. Porém, em geral com a segurança dependente da dificuldade de se decifrar os esquemas sem o auxílio de dispositivos que acelerassem os cálculos. Com a disponibilidade de computadores as técnicas de decifração se tornaram mais eficientes e acessíveis, fazendo com que a maioria dos métodos conhecidos de cifração resultassem obsoletos, tornando necessário o desenvolvimento de novas técnicas que permitam garantir a segurança de trânsito de dados entre dispositivos digitais, bem como a certificação de mensagens. Dentro do cenário descrito acima, a pesquisa em criptografia se orientou em mostrar técnicas de cifração que tornassem difícil a decifração de mensagens, mesmo com o recurso de computadores eficientes, isto levou a se buscar métodos que envolvessem uma maior sofisticação matemática. Desta forma justifica uma introdução adequada ao presente assunto, ao lado de um estudo de criptografia de chaves públicas e privadas e os aspec- tos algébricos e geométricos mais relevantes dos métodos criptográficos atuais. Este trabalho tem como objetivo geral apresentar os fundamentos da criptografia de chaves públicas: **RSA**, tendo como fio condutor a referência [7]. O objetivo específico é descre- ver o protocolo de cifração e de certificação **RSA**. Tendo como resultado final um texto que representará o trabalho executado, que também poderá ser usado como um texto para um curso, para programas de estudo individual ou orientado em criptografia.

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In his lectures, robert Wilson often recalls the lessons given by Sibyll Moholy-Nagy at the Pratt Institute in New York in the early Sixties: „We were shown slides during Sibyll Moholy-Nagy’s lectures on the history **of** **architecture**. They consisted **of** diferent forms **of** energy, ranging from a Byzantine mosaic to a prehistoric Sumerian vase and a 1922 telephone. We were bombarded by various kinds **of** visual information. It was diferent in the lessons based on verbal information. Therefore, what we felt was not what we saw. and we had to make free associations between what we saw and what we heard. Not necessarily like a collage, but as in a structure. and then there was an exam...and the students were confused and worried because they hadn’t been given the answers. The learning process was much longer than a semester, or ive semesters or even a ive-year course. It was a way **of** thinking, an experience **of** associations that spanned an entire lifetime“ (F.Quadri, F.Bertoni, r.Stearns, 1997:232). or, as Socrates taught: learning, like a life process associated with the acquisition **of** experience, with changing the character and image **of** the world, is possible only if there is awareness **of** ignorance. **architecture** should speak for itself, with its own language, there is no manifest. It is its own manifesto. Kandinsky even wrote in his 1911 essay “about the spiritual in art”: “Every epoch has its own measure **of** artistic freedom, and hence the most creative genius can not exceed the limits **of** that freedom” (Jung, 1996:314). Minimalism is not the **architecture** that confront itself, deviant **architecture** or diference work: it is deined not by what is not there, but the true values that are present and their abundance in the application - experience that is spoken with its language. Talking about minimalism in **architecture**, appears again a guiding theory from Martin Hidegger, from the famous Heraclitus- seminar led in 1966 with E. Fink: “Every day we must invent new concepts” in pursuit **of** own vision **of** the world. For imago mundi, a microcosm who embodies the world **of** the individual, is certainly a step towards to a more valuable life. “Nevertheless, one goes on working, telling stories, giving form to truth, hoping darkly, sometimes almost conidently, that truth and serene form will avail to set free the human spirit and prepare mankind for a better, lovelier, worthier life” (Mann, 1959:203).

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No caso da congruência modular não é assim tão óbvio que es- tas propriedades são satisfeitas, mas podemos veriﬁcá-las sem muito trabalho como faremos adiante. Antes porém, convém perguntar- mos para que fazer o esforço de provar que estas propriedades valem para a congruência modular. Será mera curiosidade? A resposta, naturalmente, é que não se trata apenas de curiosidade: precisamos dessas propriedades para poder utilizar de forma correta a congruên- cia modular nas contas que faremos nas próximas seções, incluindo-se a codiﬁcação de uma mensagem pelo **RSA**. É para isto que vamos provar que a congruência modular satisfaz propriedades análogas às enunciadas acima para a igualdade; mais precisamente:

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The involvement **of** TRPA1 in cold allodynia and mechanical hyperalgesia has been demonstrated using behavioral models [35]. However, its role in noxious cold and mechanical sensations is still controversial [33]. Recent studies have shown that formalin activates the primary afferent sensory neurons through specific and direct action on TRPA1, which is highly expressed by a subset **of** C-fiber TRPV1 positive nociceptors [36]. In our evaluation **of** the role TRPA1 plays in CAT’s antinociceptive mechanism, we found that CAT treatment did not change the nociceptive response caused by cinnamaldehyde. This result indicates that although CAT had an antinociceptive effect in the formalin test, that effect is related not to TRPA1 but to some other molecule in a formalin-triggered path- way, such as PGE2, NO, glutamate or kinins.

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Diffie and Hellman (1976) were the first to propose the idea **of** transmitting secret message between two communicating parties; a sender and a receiver in an insecure channel (with the presence **of** attackers). Their idea (is called **cryptosystem**) consists **of** these following properties:

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Chaum [2] reported an analogous idea for signature mechanism, as a blind signature scheme, in which entity A receives a legal signature for a document from a signer entity B without perceiving the document or acquired signature. The original blind signature developed by Chaum is dependent on **RSA** scheme [3] . In the example **of** the **RSA** scheme, decrypting an encrypted document has the same procedure as signing a document; then we simply transpose the blind signature protocol to a blind decryption protocol. Moreover, Micali [4] implemented the blind decryption protocol depending on the **RSA** scheme to a fair public Key crypto-system for making trustees oblivious. Carmenisch et al. [5] introduced an **efficient** method on a blind signature protocol dependent on Elgamal encryption scheme [6-8] , which is a different form. **RSA** scheme, the blind signature scheme proposed by Carmenisch et al. [5] cannot be straighten used in blind decryption. Absdi et al. [9] conceptually examined a typical example **of** blind computation. They described a technique **of** finding blindly the discrete logarithm. So, calculating the exponents **of** the results supposes to be extensive and consequently their manner does not solve the practical issue on the decryption Elgamal scheme.

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The principle aspects in terms **of** edge preserving concept for high density impulse noise are tested MATLAB environment and its results are evaluated with the conventional noise removal algorithms. To verify the characteristics and the quality **of** denoised images **of** the modified denoising algorithm, a variety **of** simulations are carried out on the two well-known test images: Cameraman and Lena. For the test image, the corrupted versions **of** it are generated in MATLAB environment with impulse noise at various high level noise densities 40%, 50% and 55%. Then we employ the proposed algorithm to detect impulse noise and restore the corrupted image. Fig. 1 shows the simulation results achieved through MATLAB. The metrics used for comparison are Mean square error (MSE), Peak signal to noise ratio (PSNR), Normalized Absolute Error (NAE), Normalized Cross Correlation (NCC) and are defined as follows:

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Num estudo desenvolvido por Motz e Geiseler (op. cit.), no qual procederam à avaliação da estabilidade volumétrica e do comportamento ambiental das escórias de aciaria de FAE processadas, os resultados por estes obtidos validaram a utilização deste tipo de escória como material de construção, em particular na construção de bases e sub-bases, com a obtenção de idêntico desempenho ao apresentado durante a utilização de agregados de origem basáltica. Da bibliografia consultada existem outros estudos que validam igualmente a utilização das escórias de aciaria de FAE processadas na construção de pavimentos, como é o caso dos desenvolvidos por: Garcia et al. (1999 in Graffiti, 2002); Rohde (op. cit.); Bagampadde et al. (1998 e Khan and Wahhab, 1998 in Huang et al., op. cit.); Parente et al. (2003 in Ferreira, op. cit.); Ferreira (op. cit.); Pasetto e Baldo (op. cit.); Gomes Correia et al. (2012) e Liapis e Likoydis (2012). No caso particular de Ferreira (op. cit.), este concluiu que o **ASIC** apresenta características ambientais, químicas, mineralógicas, geométricas, físicas e mecânicas que permite classifica-lo como material inerte e de desempenho mecânico elevado, podendo os resultados obtidos viabilizar a sua utilização em obras de grandes empresas de construção e a sua aceitação por parte de entidades como as Estradas de Portugal - EP, e a REde FERroviária Nacional - REFER.

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153 das recirculações do lixiviado. Porém, observa-se a tendência dos valores do pH da solução efluente se aproximarem progressivamente do valor inicial, 5,5, nos ensaios realizados no mesmo dia. Pode assim concluir-se que, em regime de percolação contínua, o pH do lixiviado não terá grandes alterações, ou estas serão pouco significativas, pelo facto de não haver tempo de contacto suficiente entre o lixiviado e o material para ocorrerem as reações químicas necessárias. No caso do ensaio do **ASIC**/areia com o lixiviado, a Figura 6.10 mostra que o pH foi sempre igual ou superior a 6,88, ou seja, cerca de 1,3 unidades de pH superior a 5,5. Esta diferença de comportamento entre a areia e a brita está associada, em parte, ao menor valor de k e à maior superfície específica da areia que da brita.

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researchers but also to provide a discussion interface **of** their supervisors and evaluators. Thus the CA²RE event develops into a visible European trigger **of** the third level educational developments. The CA²RE event builds on the rich heritage **of** the last decades… It links several local and international networks. That’s why it is found relevant for and is organized in association with the Architectural Research European Network Association (ARENA), the European Association for Architectural Education (EAAE) and the European League **of** Institutes **of** the Arts (ELIA). It is enriched by the research training traditions and experiences **of** all the incoming institutions and networks. The (research) quality criteria are the starting points for many discussions about disciplinary autonomy as well as about the impact in the communities **of** the research relevance.

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As the requirement for services rises, the total number **of** base stations possibly increased, thereby offering accession radio capacity without additional increment in radio spectrum. This fundamental precept is the base for all advanced wireless communication networks, afterward it’s enable a limited number **of** channels to assist a randomly very large number **of** user through reprocessing the channels all around the coverage area. Moreover, the cellular conception permit every part **of** user equipment amongst a nation or continent to be constructed with the similar set **of** channels thus any mobile perhaps used anyplace within the region.

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