Fingerprints play an important role in biometrics and cryptography. Their creation might be based on one-way hash functions, which should usually also be collision-resistant. But users tend to draw less attention at those fingerprints - so an attacker might hand out a similar fingerprint in order to spoof identity. The main ideas for creating such 'fuzzy fingerprints' and the creation algorithm itself are discussed in this lecture. The demonstration of the tool, that produces fuzzy fingerprints shows the practical background of this technique. / Fingerabdrücke besitzen sowohl in der Kryptographie als auch in der Biometrie eine große Bedeutung. In kryptographischen Anwendungen werden diese durch Einweg-Hash-Verfahren erzeugt, die für bestimmte Anwendungen auch kollisionsresitent sein müssen. In der Praxis schenken Benutzer diesen Fingerprints weit weniger Aufmerksamkeit - oft genügt es nur hinreichend ähnliche Fingerprints auszugeben, um die Nutzer zu täuschen Die Kriterien, die dabei erfüllt sein müssen und die Erzeugung dieser "Fuzzy Fingerprints" sind Hauptbestandteil dieses Vortrags. Durch die Demonstration eines Tools im praktischen Einsatz wird dieser abgeschlossen.

Model-based radiostereometric analysis (MBRSA) of a total ankle arthroplasty (TAA) prosthesis was studied for the first time. The TAA MBRSA system precision was determined from the double exams of 20 patients implanted with the Mobility(TM). The MTE for any direction was 0.07mm for the tibial component. The MTE was 0.09mm and the MRE was 0.51° for the talar component. The MTPM detection limits were 0.22mm and 0.85mm for the tibial and talar components. Both components followed the typical subsidence-stabilization pattern. There was little detectable continuous migration at one to two years. The median(range) MTPM at two years was 0.96mm(0.17-2.28mm) and 1.23mm(0.39-1.9 mm) for the tibial and talar components. There was no detectable inducible displacement observed for any components at two years, except one talar component. The median(range) MTPM induced by the loading at two years was 0.08mm(0.03-0.18mm) and 0.39mm(0.27-1.06mm) for the tibial and talar components.

The goal of this thesis was to assess the validity of a computer simulated Radiostereometric Analysis (RSA) environment and assess the use of novel migration origin styles for use in the assessment of spinal fusion success in post-surgical adolescent idiopathic scoliosis patients. A parallel precision study was conducted with a physical phantom and identical computed simulated spinal fusion model. This study was used to conduct a precision validation of the simulate RSA environment. The origin style assessment was done in comparison with the translational and rotational Limits of Clinical Significance defined by Pape et al (2002) and Johnsson et al (2002) respectively [1], [2]. This thesis concluded that the use of a simulated environment is an acceptable method for the creation of phantom RSA research studies. It was also shown that both the Apex and Dual Origin Styles equally accurate and precise.

Knee osteoarthritis is a debilitating disease causing pain and disability in adults. Biomechanical factors including obesity, abnormal magnitude and load distribution have been cited to play a role in its initiation and progression with its definite cause being multi-factorial. Total knee arthroplasty has become the treatment of choice for knee osteoarthritis and although the procedure is mostly successful, there are some patients who experience implant failures which necessitates revision surgery. Revision surgery is more complicated and thus there is the need to monitor patients who have undergone TKA so as ensure better outcomes and also address problems much earlier. Objective methods like Radiostereometric Analysis (RSA) has proven to be a good tool at diagnosing these implant failures. Inducible displacement with RSA has the potential to serve as a one-time measure to diagnose implant failures. Previous studies have applied loads to induce motion to the knee in various ways- squatting, exercising and weight-bearing on the affected limb. This was not standardized and caused wide variations in the data. This work looked at refining a device used to apply standardized loads to the knee resulting in a more portable and faster way of applying load to the joint. Gait analysis is used to assess implant function pre and post surgery. Some gait patterns have also been related to implant failure. Previous works have focussed primarily on associations between well-working implants (non-revised patients) and these gait patterns (adduction moments and flexion angles). This work focussed on any differences in the gait patterns between patients who did not undergo revision surgery and those that did. Although most parameter differences did not reach statistical differences, they point to important trends that may explain the causative factors (adduction moments) whiles others may point to the effects of disease progression (external rotation).

This thesis, Parallels in portraits of leadership in mega churches of Gauteng (RSA) and Florida (USA), the researcher, studied literature on church leadership with special reference to the leadership of mega churches. He researched issues relating to the nature of church leadership by exploring relevant Bible passages, the lives of certain Bible characters that the Bible presents as good but not perfect leaders, as well as relevant key theological conceptions of leadership. The study accordingly also reviewed different models of church leadership on the hand of a study of some Bible passages and current theological thinking about the matter. The thesis demonstrated that the leadership of mega churches requires certain leadership qualities, values, and competencies. The contribution of the study lies therein that it confirmed and identified through a comparative empirical analysis of details collected through basic research in mega churches of Florida (USA) and Gauteng (RSA) the qualities, values and competencies that are essential for successful leadership of mega churches in very different contexts and church families. The study therefore recommends a desirable leadership style and essential qualities for effective church leadership of mega churches. The study also makes a contribution to the theological understanding of a new but growing church type in urban settings, the mega church; and is of great value to those that lead and study such churches. / PhD, Biblical Studies, North-West University, Vaal Triangle Campus, 2012

This thesis presents the ASIC implementation of the RSA algorithm, which is one of the most widely used Public Key Cryptosystems (PKC) in the world. In RSA Cryptosystem, modular exponentiation of large integers is used for both encryption and decryption processes. The security of the RSA increases as the number of the bits increase. However, as the numbers become larger (1024-bit or higher) the challenge is to provide architectures, which can be implemented in hardware, operate at high clock speeds, use a minimum of resources and can be used in real-time applications. In this thesis, a semi-custom VLSI implementation of the RSA Cryptosystem is performed for both 512-bit and 1024-bit processes using 0.35&micro / m AMI Semiconductor Standard Cell Libraries. By suiting the design into a systolic and regular architecture, the broadcasting signals and routing delays are minimized in the implementation. With this regular architecture, the results of 3ns clock period (627Kbps) using 87K gates (8.7mm2 with I/O pads) for the 512-bit implementation, and 4ns clock period (237Kps) using 132K gates (10.4mm2 with I/O pads) for the 1024-bit implementation have been achieved. These results are obtained for the worst-case conditions and they include the post-layout routing delays. The design is also verified in real time using the Xilinx V2000E FPGA on the Celoxica RC1000 Hardware. The 1024-bit VLSI implementation has been sent to IMEC for fabrication as a prototype chip through Europractice Multi-Project Wafer (MPW) runs.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-07-25T20:07:22Z No. of bitstreams: 1 2013 - Kelly Cristina Santos Alexandre de Lima.pdf: 1635869 bytes, checksum: 038861f43fdfe8411b10d93fc0f8533a (MD5) / Made available in DSpace on 2017-07-25T20:07:22Z (GMT). No. of bitstreams: 1 2013 - Kelly Cristina Santos Alexandre de Lima.pdf: 1635869 bytes, checksum: 038861f43fdfe8411b10d93fc0f8533a (MD5) Previous issue date: 2013-04-15 / This study aims to provide a discussion of the concepts involving encryption, through its application of prime numbers, and possible links with education. The criterion used to choose one or other cryptographic system was subjective, many systems have not been addressed, even containing intrinsic relations with the theme. The necessity to exchange confidential information urged the rise of art to encode messages, the virtual network and its millions of users identified the need for a system using public key and at the same time, safe. RSA came to supply the needs of a society that increasingly conducts its banking, commercial and social web. One issue which needs to be thought concerning the way how the contents of the called Number Theory have been presented and learned at school. Something that is traditionally consecrated as boring and meaningless. The art of cryptography brings relevant topics to think about mathematical concepts, providing an education for Troubleshooting. The paths taken, thereafter, provide meaningful experiences for the subject, in emancipatory education, as suggested by Adorno and Ranci?re. Suggested activities from different coding systems intend to instigate students and educators to reconsider the different possibilities of a problem, raising the sensitivity of thinking and find ways to solve and not repeat the mechanisms of a mathematical algorithm, so that the educational act passes by the complex circumstances that present themselves today. / Este trabalho visa estabelecer uma discuss?o sobre os conceitos envolvendo criptografia, atrav?s de sua aplica??o dos n?meros primos, e as poss?veis rela??es com a educa??o. O crit?rio utilizado para optar por este ou aquele sistema criptogr?fico foi subjetivo; muitos sistemas n?o foram abordados, mesmo contendo rela??es intr?nsecas com a tem?tica. A necessidade de troca de informa??es sigilosas instigou o surgimento da arte de codificar mensagens; a rede virtual e seus milh?es de usu?rios apontou a necessidade de um sistema utilizando chave p?blica e, ao mesmo tempo, seguro. O RSA veio para suprir as necessidades de uma sociedade que, cada vez mais, realiza suas transa??es banc?rias, comerciais e sociais via web. Uma quest?o que carece ser pensada diz respeito ? maneira como os conte?dos da chamada Teoria dos N?meros t?m sido apresentados e trabalhados na escola. Algo que ? tradicionalmente consagrado como enfadonho e sem sentido. A arte da criptografia traz consigo temas relevantes para se pensar nos conceitos matem?ticos, propiciando um ensino por Resolu??o de Problemas. Os caminhos percorridos, a partir da?, propiciam experi?ncias significativas para o sujeito, numa educa??o emancipat?ria, como propuseram Adorno e Ranci?re. As atividades sugeridas a partir de diferentes sistemas de codifica??o pretendem instigar os educandos e os educadores a repensar as diferentes possibilidades de um problema, suscitando a sensibilidade do pensar e de buscar maneiras para resolver e n?o repetir os mecanismos de um algoritmo matem?tico, para que o ato educativo perpasse as circunst?ncias complexas que se apresentam na atualidade.

Today the Internet is used more and more as a transportation for information. Much of the information is confidential and should not be read by those not privileged. To protect the information from unauthorized access cryptography can be applied. The cryptography algorithms in use today all have their pros and cons. They are therefore suited for different applications. We've compared three different cryptography algorithms RSA, DES and IDEA. What we've focused on is the level of security the algorithms give. DES and IDEA are symmetrical algorithms and as such they use the same key for encryption and decryption. RSA on the other hand is an asymmetrical algorithm. Asymmetrical algorithms use two keys, one for encryption and the other for decryption. The factor that is most decisive for the algorithms security is the length of the key that is used. What is interesting concerning the keys is that security increases linearly for the symmetrical algorithms, as the key length increases. For asymmetrical algorithms it increases on an expontiell curve. RSA has got a big advantage compared to DES and IDEA. The advantage is key management. RSA can be used to exchange symmetrical keys in a safe way. The big disadvantage of RSA is that it's very slow to use. According to measurements that we have seen it is about 3 to 4 times slower then DES and IDEA during encryption, when using a key length of 1024 bits. At decryption RSA is about 120 times slower using a key length of 1024 bits. DES on the other hand is slower then newer symmetrical algorithms such as IDEA. This makes it uncalled for to use it in it?s original shape as it?s obsolete and insecure. Using DES will only give a false sense of security, unless the information doesn't need to be secure for more then a short time period. IDEA offers high using it's 128 bits key and it's also the fastest of the two symmetrical algorithms, compared to the level of security that it offers. IDEA today has no known weaknesses and it has not been broken. Of the three IDEA is the best choice to use when it concerns cryptography of information, for example information which is stored on a hard disc, or information that is sent in e-commerce.

Graphics Processing Units (GPU) and their development tools have advanced recently, and industry has become more interested in using them. Among several development frameworks for GPU(s), OpenCL provides a programming environment to write portable code that can run in parallel. This report describes two case studies of algorithm implementations in OpenCL. The first algorithm is Median Filtering which is a widely used image processing algorithm. The other algorithm is RSA which is a popular algorithm used in encryption. The CPU and GPU implementations of these algorithms are compared in method and speed. The GPU implementations are also evaluated by efficiency, stability, scalability and portability. We find that the GPU implementations perform better overall with some exceptions. We see that a pure GPU solution is not always the best and that a hybrid solution with both CPU and GPU may be to prefer in some cases.

The aim of this study is to determine the security relevance of farm attacks in South Africa. This is based on the propositions that indications exist that farm attacks in the RSA reflect more than common criminality; that the combating of farm attacks requires specific measures; and that farm attacks in other African states, as well as prior to 1994 in some instances also in South Africa, had demonstrated specific political motives. In the search for the underlying causes behind the incidence of farm attacks, aspects such as the occurence of farm attacks elsewhere in Africa; the political history of the RSA; the dynamics associated with an increase in crime during political transition; land reform; and the extent of farm attacks in the RSA, were analysed. The occurence of farm attacks seems not to be unique to South Africa, as attacks of this nature also occurred in other African states such as Kenya and Zimbabwe. As could have been expected from international experience, crime increased substantially in South Africa during a period of radical political transition. Farm attacks, which inherently manifest as violent crimes, also increased, especially during the period between 1997 and 2001. Developments during South Africa’s political past led to a situation in which a substantial part of the population lost not only their political rights, but also their land. As a result, land reform is high on the agenda of those who feel deprived, as well as that of the government. The findings reached by commissions of enquiry and research into the causes of farm attacks reveal that crime is the single most important motive for farm attacks. Other motives were identified in single cases, but no common sinister motive or any specific organisation instigating farm attacks could be established. Although the level of trust between the farming community and government has in some cases suffered considerable harm, both parties are bound to the combating of farm attacks, including participation in the implementation of combined strategies such as the Rural Safety Plan. The occurrence of farm attacks is clearly a significant security issue. Although it is not yet considered as posing an immediate direct threat to national security, it has already been recognized that farm attacks could negatively impact on food security. The possibility of this phenomenon developing into a full-fledged national security issue, can thus not be excluded. / Dissertation (M (Security Studies))--University of Pretoria, 2006. / Political Sciences / unrestricted