Diploma thesis deals with an anonymous transmit of messages using protocol for anonymous authentication. In first part, we introduce theoretical familiarization to the issues and description protocol for anonymous authentication. Further, it describes the suggestion of the communication between the client and the server. Finally, contains a description of the created system for anonymous transmit of messages, which consists of the server and clients, who can leave challenges on the server for other users and they obtains challenges from the server. The thesis explains how to start and control program. There are also discussed methods of computing verification values, encryption keys and messages and authentication of receivers.

This thesis analyzes Application Layer security protocols for certificate enrollment and management. EDHOC, Ephemeral Diffie-HellmanOver COSE, is a recently developed key exchange protocol whichis designed to provide authentication and key-exchange functionality with compact message sizes and minimum round-trip-time. The workof this thesis extends the EDHOC protocol with a certificate enrollment functionality, targeting IoT constrained devices and it has been implemented for analysis and evaluation purposes. The main scope of this document is to study the security, performance and scalability (in descendingorder of importance) of enrollment over EDHOC compared to other certificate enrollment protocols. / Detta examensarbete analyserar säkerhetsprotokoll av typen ApplicationLayer för certifikatregistrering och hantering. EDHOC, Ephemeral Diffie-Hellman Over COSE, har implementerats, analyserats och utvärderats. EDHOC är ett nyligen utvecklat Application Layer-protokoll som är utformat för att tillhandahålla autentiserings- och nyckelfunktionsfunktioner med kompakta meddelandestorlekar och minimala rundturstider, inriktat på IoT-begränsade enheter. Huvudområdet för examensarbetet är att studera säkerhet, prestanda och skalbarhet (i fallande ordning av betydelse) hos EDHOC jämfört med andra föreslagna Application Layer-säkerhetsprotokoll som utför certifikatsskrivning.

Ensuring trustworthiness through mobile nodes is a serious issue. Indeed, securing the routing protocols in Mobile Ad Hoc Network (MANET) is of paramount importance. A key exchange cryptography technique is one such protocol. Trust relationship between mobile nodes is essential. Without it, security will be further threatened. The absence of infrastructure and a dynamic topology changing reduce the performance of security and trust in mobile networks. Current proposed security solutions cannot cope with eavesdroppers and misbehaving mobile nodes. Practically, designing a key exchange cryptography system is very challenging. Some key exchanges have been proposed which cause decrease in power, memory and bandwidth and increase in computational processing for each mobile node in the network consequently leading to a high overhead. Some of the trust models have been investigated to calculate the level of trust based on recommendations or reputations. These might be the cause of internal malicious attacks. Our contribution is to provide trustworthy communications among the mobile nodes in the network in order to discourage untrustworthy mobile nodes from participating in the network to gain services. As a result, we have presented an Elliptic Curve Diffie-Hellman key exchange and trust framework mechanism for securing the communication between mobile nodes. Since our proposed model uses a small key and less calculation, it leads to a reduction in memory and bandwidth without compromising on security level. Another advantage of the trust framework model is to detect and eliminate any kind of distrust route that contain any malicious node or suspects its behavior.

The thesis is focused on implementation of aplication for secure telephone communication on data network. Application is developed for operating system Android. For call management is responsible signaling protocol SIP and for transfer of voice data is used protocol RTP. For security of call is first created cryptografic key for symetric cryptography. After generating key is established call, which is encrypted by symetric cipher AES. Encrypting between communicating sides is provided in application or on microSD card. Part of solution is measurement of speed of cryptographic primitives, which are used for secure call.

The thesis deals with the problems of user authentication. The first chapter analyzes the problem of authentication, its methods and its utilization. The second chapter presents the different security options for communication. The chapter describes security, communication and authentication protocols. There is the 2D barcode QR Code described at the end of the chapter. The third chapter is devoted to ASP.NET technology, its development and possibilities of utilization. Attention is focused on web form and server controls. There is an analysis of elements of cookies and possibilities of their use. The last chapter consists of a practical part, which describes the development of a web application. There is a description of the parts of application, such as the database, the Web navigation, master pages and etc. in the following chapter. The cardinal part of the chapter consists of an analysis and implementation of forms authentication, the attribute authentication and authentication with QR code. Finally, there is a description of way how to secure the communication by using a certificate.

Ensuring trustworthiness through mobile nodes is a serious issue. Indeed, securing the routing protocols in Mobile Ad Hoc Network (MANET) is of paramount importance. A key exchange cryptography technique is one such protocol. Trust relationship between mobile nodes is essential. Without it, security will be further threatened. The absence of infrastructure and a dynamic topology changing reduce the performance of security and trust in mobile networks. Current proposed security solutions cannot cope with eavesdroppers and misbehaving mobile nodes. Practically, designing a key exchange cryptography system is very challenging. Some key exchanges have been proposed which cause decrease in power, memory and bandwidth and increase in computational processing for each mobile node in the network consequently leading to a high overhead. Some of the trust models have been investigated to calculate the level of trust based on recommendations or reputations. These might be the cause of internal malicious attacks. Our contribution is to provide trustworthy communications among the mobile nodes in the network in order to discourage untrustworthy mobile nodes from participating in the network to gain services. As a result, we have presented an Elliptic Curve Diffie-Hellman key exchange and trust framework mechanism for securing the communication between mobile nodes. Since our proposed model uses a small key and less calculation, it leads to a reduction in memory and bandwidth without compromising on security level. Another advantage of the trust framework model is to detect and eliminate any kind of distrust route that contain any malicious node or suspects its behavior.

The Signal protocol can be considered state-of-the-art when it comes to secure messaging, but advances in quantum computing stress the importance of finding post-quantum resistant alternatives to its asymmetric cryptographic primitives. The aim is to determine whether existing post-quantum cryptography can be used as a drop-in replacement for the public-key cryptography currently used in the Signal protocol and what the performance trade-offs may be. An implementation of the Signal protocol using commutative supersingular isogeny Diffie-Hellman (CSIDH) key exchange operations in place of elliptic-curve Diffie-Hellman (ECDH) is proposed. The benchmark results on a Samsung Galaxy Note 8 mobile device equipped with a 64-bit Samsung Exynos 9 (8895) octa-core CPU shows that it takes roughly 8 seconds to initialize a session using CSIDH-512 and over 40 seconds using CSIDH-1024, without platform specific optimization. To the best of our knowledge, the proposed implementation is the first post-quantum resistant Signal protocol implementation and the first evaluation of using CSIDH as a drop-in replacement for ECDH in a communication protocol.

Elliptic curve cryptography (ECC) has played a significant role on secure devices since it was introduced by Koblitz and Miller more than three decades ago. The great demand for ECC is created by its shorter key length while it provides an equivalent security level in comparison to previously introduced public-key cryptosystems (e.g.RSA). From an implementation point of view a shorter key length means a higher processing speed, smaller power consumption, and silicon area requirement. Scalar multiplication is the main operation in Elliptic Curve Diffie-Hellman (ECDH), which is a key-agreement protocol using ECC. As shown in the prior literature, this operation is both vulnerable to Power Analysis attack and requires a large amount of time. Therefore, a lot of research has focused on enhancing the performance and security of scalar multiplication. In this work, we describe three schemes to counter power analysis cryptographic attacks. The first scheme provides improved security at the expense of a very small cost of additional hardware overhead; its basic idea is to randomize independent field operations in order to have multiple power consumption traces for each point operation. In the second scheme, we introduce an atomic block that consists of addition, multiplication and addition [A-M-A]. This technique provides a very good scalar multiplication protection but with increased computation cost. The third scheme provides both security and speed by adopting the second tech- nique and enhancing the instruction-level parallelism at the atomic level. As a result, the last scheme also provides a reduction in computing time. With these schemes the users can optimize the trade-off between speed, cost, and security level according to their needs and resources. / Graduate / 0544 / 0984 / z.mohaimeed@gmail.com

Made available in DSpace on 2014-12-17T14:55:40Z (GMT). No. of bitstreams: 1 JoseMF.pdf: 585000 bytes, checksum: d743090da952a3d8b178ffb4048abd4b (MD5) Previous issue date: 2009-12-16 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / 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 / Identifica??o por r?dio freq??ncia, tamb?m chamada de RFID (Radio Frequency Identification), representa uma tecnologia de transmiss?o de dados sem fio. Estes dados s?o relacionados principalmente a c?digos de identifica??o. A tecnologia RFID vem apresentando um grande potencial de utiliza??o em setores da automa??o industrial, residencial e hospitalar. No entanto, estas aplica??es podem resultar em riscos a seguran?a e privacidade dos usu?rios. Recentemente, pesquisadores v?m apresentando poss?veis solu??es as amea?as de seguran?a da tecnologia. Entre estas solu??es est?o os protocolos de distribui??o de chaves criptogr?ficas. O presente trabalho tem como objetivo realizar uma avalia??o de desempenho dos protocolos de Criptografia Neural e Diffie-Hellman na gera??o de chaves em sistemas RFID. Para isso, iremos mensurar o tempo de processamento destes protocolos. Para os testes foi desenvolvido uma plataforma em FPGA (Field-Programmable Gate Array) com o processador embarcado Nios IIr. Sobre esta plataforma foram utilizados os protocolos de Criptografia Neural e Diffie-Hellman no processo de gera??o de chaves criptogr?ficas. A metodologia de pesquisa baseia-se na agrega??o de conhecimento ao desenvolvimento de novos sistemas RFID atrav?s de uma an?lise comparativa entre esses dois protocolos de seguran?a da informa??o. As principais contribui??es deste trabalho s?o: avalia??o de desempenho dos protocolos (Diffie- Hellman e Criptografia Neural) em uma plataforma embarcada e um levantamento bibliogr?fico de pesquisas relacionadas ? seguran?a da informa??o em sistemas RFID. Nos resultados obtidos foi poss?vel observar que o protocolo de Diffie-Hellman ? mais apropriado para sistemas RFID

Current needs of human communication came to status, when most of transferred messages are considered as private and transition over non-secured communication lines in open form is not possible. That originated a lot of different methods for securing of messages and transfers in ciphered form. Two mainstreams were established, symmetric cryptography and asymmetric cryptography. Second of mentioned groups is based on usage of two information – keys, when one of then is broadly known and is public and second, well protected and private. Using a public key it is possible to establish a cryptogram of message, but for deciphering it is necessary to know private key. Asymmetric methods are based on mathematical problems, for which there is not an effective computing algorithm. This thesis are focused for asymmetric cryptosystems based on discrete logarithm problem, where ciphering of message using public key is very easy and quick, but deciphering without knowledge of private key is extremely time consuming process. Work describes a mathematical base of discrete logarithm problem, its’ properties and methods developed for solving of this problem. Descriptions of particular cryptosystems are given, i.e. ElGamal cryptosystem, Diffie-Hellman protocol and DSA. Second part of thesis is focused for web application developed as study support of discrete logarithm problem and of cryptosystems using this problem. It describes functional and graphical interface, work with it and options given to user working with application. Mentions also lessons for user which should help with understanding of described problems and practicing.