The first topic of this thesis is a cell-based design solution of 4¡Ñ8 scanning decoder using RC5 protocol for DECT handsets. It is a keypad scanner ASIC without any embedded microprocessor nor internal ROMs. The keypad scanner uses RC5 transfer protocol which is compatible with remote control and wireless handsets. The keypad scanner built in the handsets must meet the requirement of low power consumption and small die size to avoid shortening the battery lift and increasing chip cost. The proposed ASIC design possesses both of the required advantages. The second topic is a high-performance SRAM using current sense amplifier. Current sensing in SRAMs is very promising method to achieve high speed operations in low-voltage applications. This topic present a current sense amplifier circuit as well as its simulation results.

The aim of the thesis is to explain and introduce the indiviudal components and control proceedings in the systems of automatic control of intelligent houses. The thesis is divided into three parts. In the first part I deal with the general description and structure of the house automatic systems, their availability and application in wiring practise. The second part is focused on the proceedings used in RC5 infra-red area and the most used X10 PowerLine protocol and its processing by AVR microprocessors. The third part is concentrated on the practical construction of a module with a microprocessor enabling the development and education of user applications for the substance of the automation system and that extend it in other possibilities of communication such as ethernet and WiFi networks, eventually GSM mobile network.

This thesis consists of two topics. We proposed a low power half-run RC5 cipher for portable biomedical devices in the first part of this thesis. The second topic is to realize a frequency-shift readout system for FPW-based biosensors. In the first topic, a half-round low-power RC5 encryption structure is proposed. To reduce hardware cost as well as power consumption, the proposed RC5 cipher adopts a resource-sharing approach, where only one adder/subtractor, one bi-directional barrel shifter, and one XOR with 32-bit bus width are used to carry out the entire design. Two data paths are switched through the combination of four multiplexers in the encryption/decryption procedure. For the sake of power reduction, the clock in the key expansion can be turned off when all subkeys are generated. In the second topic, an IgE antigen concentration measurement system using a frequency-shift readout method for a two-port FPW (flexural plate-wave) allergy biosensor is presented. The proposed frequency-shift readout method adopts a peak detecting scheme to detect the resonant frequency. A linear frequency generator, a pair of peak detectors, two registers, and an subtractor are only needed in our system. According to the characteristics of the FPW allergy biosensor, the frequency sweep range is limited in a range of 2 MHz to 4 MHz. The precision of the measured frequency is proved to the 4.2 kHz/mV, which is for better than that of existing designs.

In this thesis, two finalists of the AES (Advanced Encryption Standard) contest, RC6 developed by Rivest et al, Twofish proposed by Schneier et al, and preceding algorithm of RC6 cipher, RC5, are studied. The strength of ciphers to cryptanalytic attacks is measured according to different criteria. The studied evaluation criteria are the avalanche criterion and its derivations. After theimplementation of the algorithms and the test procedures, they are compared with each other. Different test criteria, including avalanche criterion, avalanche weight distribution (AWD) for randomness of RC5, RC6 and Twofish algorithms are applied / and the S-boxes of the Twofish algorithm are analyzed according to nonlinearity criterion. The avalanche criteria results of RC6 and Twofish are compared with NIST (National Institute of Standards and Technology) Statistical Test Suite results.

The purpose of this thesis work was to conduct a general research on existing security techniques and come up with a considerable algorithm for data security in cloud storage. Cloud storage is an infrastructure or is a model of computer data storage in which the digital data is stored in logical pools. It unifies object storage for both developers and enterprises, from live applications data to cloud archival. It help to save valuable space on PC computers or mobile devices and provides the easy storage and access of data anywhere in the world. However, just as the benefits of cloud computing abounds, so also are the risks involved. If data are not well secured or encrypted before deployment for storage in the cloud, in case of negligence on the side of the developers, then hackers can gain unauthorized access to the data. The behavior of existing security algorithms on data were studied, the encryption and decryption process of the each algorithm on data was studied and also their weaknesses against attacks. Apart from data encryption, security policies also plays an important roll in cloud storage which was also covered in this report. The research work was conducted through the use of online publications, literature review, books, academic publications and reputable research materials. The study showed that regardless of the challenges in cloud storage, there is still a suitable algorithm for protecting data against attack in the cloud.