applications discussed with dynamic, cryptographic, robust and string hashing techniques. In certain applications where the memory allocation for hashfunctions can be inadequate, a chain hashing technique comes into play where the hashfunctions are linked using external memory.  presents partial work of this project, verification of SHA-256 algorithm usingUVM. Paper presents the analysis of the SHA-256 algorithm, and a UVM platform is used to validate SHA-256 as IP. In fact the same procedure can be reproduced to test the SHA-256 and MD5. This reference is used over the implementation of project. Note that although a few compo- nents of testing environment might change with respect to DUT, the framework remains the same. Saying that, SHA256 or MD5 does not make a major difference in the UVM frame- work.  is a good reference to understand the re-usability of UVM testing framework. The paper presents the concepts of re-usability using few case studies. can be reproduced to construct a UVM framework for SHA-256 followed by  to reuse the framework for MD5 algorithm. These two are the most relevant and significant references used over the implemen- tation of this project. presents a method to implement automated verification. UVM is a complete framework that includes coverage metrics, self-checking testbenches and automatic test generation. Even though the DUT here is not complex but rather simple IP’s, complete utilization of UVM is another goal.
A digital signature is a cryptographic algorithm which includes the process of signature generation and signature verification. A signer uses the generation process to create a digital signature on the data, and the verifier verifies the authenticity of the signature by using the verification process. The private key is used to generate the signature and must remain secret, while the public key is on the verification process (Bhala et al., 2011). Digital signatures are widely used in various applications such as electronic commerce, banks, distributing software, and in detecting forgery or tampering. They are corresponds of handwritten signatures which can be transmitted within a computer network. Only the signer of the message can make the signature, and the other people can recognize easily as belonging to the signer. The digital signature has three types of services such as (Gola et al., 2014):
ΔC, ΔD, ΔE = 0) in the middle of calculation and collision will find easily as shown in Table3. Although SHA-1 tried to remove this flaw but the weakness still remained [9, 10]. In fact differential cryptanalysis works when the attacker can predict the evolution of differences with a high probability because of existence of Neutral Bits. It is easy to cancel a difference in the state by changing compress functions before starting next round or by creating another difference in the messages that is prepared in our algorithm but it is obvious that they should change by a procedure to keep the solidarity regarding to Merkle-Damgard theory which proved that if the compression function is collision-resistant, then the hash function is collision resistant as well and mathematical induction need solidarity .
Since 2005, many collision attacks have been shown for commonly used and stan- dardized hashfunctions. In particular, the collision attacks of Wang et al. [17,18] on MD5 and SHA-1 have convinced many cryptographers that these widely de- ployed hashfunctions can no longer be considered secure. As a consequence, NIST has proposed the transition from SHA-1 to the SHA-2 family. Many com- panies and organization follow this advice and migrate to SHA-2. Additionally, SHA-2 is faster on many platforms than the recently chosen winner of the SHA-3 competition . Hence, NIST explicitly recommends both, SHA-2 and SHA-3. Therefore, the cryptanalysis of SHA-2 is still of high interest.
mapping the designs to the FPGAs devices. The functionality of the implementa- tions was initially verified via Post-Place and Route simulations using the Model Technologys ModelSim simulator. A large set of test vectors apart from those pro- vided by the standard were used. Also, downloading to development boards and additional functional verification were performed via the ChipScope tool of Xilinx. The number of the applied pipeline stages in each hash function’s design that has to be evaluated, depends on the number of the iterations that this hash function performs. If the number of iterations is divisible by the number of the applied pipeline stages then all the pipeline stages will be fully exploited without need for inserting pipeline stalls (where some pipeline stages do not process any values). Thus, only these numbers of the applied pipelined stages must be evaluated through development of the corresponding hashfunctions’ pipelined designs so as to define the optimum version in each case. In all other versions of pipelined designs there will be, in certain time instances, idle pipeline stages which results to severe degradation of the hashfunctions design performance.
The UVM (Universal Verification Methodology) was introduced in December 2009, by a technical Sub committee of Accellera. The Universal Verification Methodology (UVM) is a standardized methodology for verifying integrated circuit designs. UVM is derived mainly from the OVM (Open Verification Methodology) which was, to a large part, based on the eRM (e Reuse Methodology) for the e Verification Language developed by Verisity Design in 2001. The UVM class library brings much automation to the SystemVerilog language such as sequences and data automation features (packing, copy, compare) etc., and unlike the previous methodologies developed independently by the simulator vendors, is an Accellera standard with support from multiple vendors: Aldec, Cadence, Mentor Graphics, and Synopsys.
The reduction in Critical Path for the longest calculation allows the remainder of the SHA operation to be unrolled and therefore completed in one, rather than multiple, clock cycles. It is found in that unfolding the design for two operations (so performing two operations in one clock cycle) gives a factor-of-two speed improvement for the same increase in area. Unfolding is also performed in , increasing throughput to 76Mbit/sec in conjunction with pipelining. Changing the architecture to a pipeline allows for simultaneous processing of blocks while not affecting the SHA operation. Using the pipeline also gives a level of delay balancing to the circuit, preventing incorrect signal propagation through a circuit and causing an incorrect message digest. Use of these improvement techniques comes at a gate penalty and therefore would not be ideal for applications where power consumption is critical.
Furthermore, the introduced SHA-256hash core was compared with a conventional 4-stage pipeline (see Figure 3) where no special optimization effort has been paid to optimize the operation block. This was done so as to exhibit the efficiency of the proposed design methods and produced SHA-256 core. The proposed SHA-256 operation block results in a 170% increase of throughput and 35% area increase. This area penalty is about 10% for the whole security scheme that we considered for the IPSec and which also includes AES encryption algorithm. This is based on the fact that an IPSec core includes the AES, hash function and the corresponding control logic. Based on previous AES implementations [Hodjat et al. 2004; Granado-Criado et al. 2010] it is derived that their area sizes are similar to that of the of the SHA-256 core. Thus, assuming a 10% area overhead for the control logic the area penalty is about 10% for the whole security scheme. Since recent implementations of AES have much higher throughput and operating frequencies, this means that the proposed implementation achieves a great increase of throughput for the whole security scheme with a minor area penalty.
Discussing the coverage metric before the stimulus helps in our understanding of the types of stimulus that should be used. As we already have concentrated on the types of conditions that we want to cover, we can come up with tests in a more efficient way. We would also not be repeating tests if we know that we’ve already developed a test to cover a feature. More tests were added in response to certain cover points not being met. An important observation from verification of the cache is that, while random stimulus is very useful, directed test cases with some randomness in the data are also very important for reaching our coverage goal. UVM sequences are used to develop these tests. A few tests were developed for OOP testbench too for comparison to the UVM tests. Each section describes the sequence used for the test. A common sequence used for all the tests is the reset_sequence, which as the name suggests resets the cache and brings the DUT to a known state.
Hardware description languages are tools used by engineers to specify abstract models of dig- ital circuits to translate them into real hardware, as the design progresses towards completion, hardware verification is performed using Hardware verification languages like SystemVerilog. The purpose of verification is to demonstrate the functional correctness of a design. Verification is achieved by means of a testbench, which is an abstract system that provides stimulus to the inputs of design under test (DUT). Functional verification shows that design implementation is in correspondence to the specification. Typically, the testbench implements a reference model of the functionality that needs to be verified and compare the results from that model with the results of the design under test. The role of functional verification is to verify if the design meets the specification but not to prove it .
Back when fabrication of devices with dimensions in microns was a wonder, designs were not as intricate, and the prime focus was on design more than verification. However, now, with rapid advancement in technology scaling, verification has become more of a challenge. As the designs became smaller, more space became available on the chip, and it gave the designer a chance to add new features and capabilities to the design. As a result, many sensors were built right onto the chip instead of connecting it with external sensors.
Another use case scenario where updates come in the form of insertions of new elements or modifications of existing data are distributed storage systems for managing structured data, such as Cloud Bigtable by Google . It is designed to scale to a very large size, like petabytes of data across thousands of commodity servers. Its data model is described as persistent multidimensional sorted map, and it uses Google SSTable file format to internally store data . Each SSTable contains a sequence of blocks typically of 64KB in size and every block has its own unique index that is used to locate the block. Using this kind of file formats where blocks have its unique numbers, incremental hashing can be successfully implemented despite the variable-size setting: In addition to the update operation, in order to perform incremental hash calculations, we introduce additional insert and delete operations.
roots of the quartic polynomial in to (17) and (18), two 4 th degree polynomials with only one variable (x) are obtained. When solved, each polynomial will give either two or four real roots. Out of these, any two roots will satisfy both (17) and (18) along with corresponding value of y. Using any one out of two, second Joint displacements (θ 2 ) are computed using equation (13) and results are
From model generation, analysis and design to visualization and result verification, STAAD Pro is the professional’s choice for steel, concrete, timber, aluminum and cold-formed steel design of low and high-rise buildings, culverts, petrochemical plants, tunnels, bridges, piles and much more. To perform an accurate analysis a structural engineer must determine such information as structural loads, geometry, support conditions, and materials properties. The results of such an analysis typically include support reactions, stresses and displacements. This information is then compared to criteria that indicate the conditions of failure.
The data was collected by using the questionnaire method, which is the most widely used method for data collection for both descriptive and analytical surveys. Furthermore, the questionnaire is a fast and easy method of data collection and more accurate when starting processing and analyzing the collected data. The target population for this research includes all classified contractors according to PCU. There exist 331 classified contractors in 2015 in Gaza Strip. According to PCU construction works divided into five major areas (roads, Buildings, electromechanical, water / sewage, public works and maintenance) each one of these areas contains five classes (class one, class two, class three, class four, and class five). The contractor can have more than one classification in different areas of the above-mentioned five areas.
explored the capabilities of ECSM by conducting the experimental investigation on the micro machining of electrically nonconductive e-glass–fibre–epoxy composite during electrochemical spark machining using specially designed square cross section with centrally micro hole brass tool and different diameter round-shaped micro tools made of IS-3748 steel. The influence of the fabricated ECSM parameters on the material removal rate and overcut on generated hole radius were investigated. The shape of the tool has a strong influence on the geometry of the machined hole. Flat side wall shaped tool performed better as compared to cylindrical tools while machining the holes as reported by Eunice et al. . Yang et al.  used spherical end shape tool i.e. electrode and claimed that the curved surface of the spherical tool reduces the contact area between the electrode and the workpiece, thus facilitating the flow of electrolyte to the electrode end and enables rapid formation of gas film, resulting generates better micro-hole. Wei et al.  presented the technique of electrochemical discharge machining (ECDM) gravity- feed drilling using micro-drills. They claimed that the
The electricity produced is stored in a battery, which is then utilized for supplying electricity to induction motor for providing motive power to the vehicle end the electricity required for carrying out the electrolysis is generated from solar energy by using a solar panel which is mounted on a vehicle.