Authentication Comparison of Telecommunications Technology Using A3, A8, A5 and Rijndael Algorithms

The purpose of the research is to analyze the comparison of technology, network and security aspect between CDMA and GSM (Global System for Car communication). Using a comparative analysis research method between CDMA and GSM technologies that includes comparisons of network, technology, and security aspects. Using references from previous research on cellular telecommunications, the introduction of CDMA and GSM technologies to aspects of technology, networking and security. The results show that the technological aspect, CDMA used advanced spectrum technology that can provide superior sound quality and GSM uses a spectrum division technology that makes communication constant. From the network aspect, CDMA used direct-spreading spectrum (DS-CDMA) and GSM network is divided into three main systems: switching system (SS), base station system (BSS), and operating system and support (OSS). As well as security aspects, the GSM uses A3 and A8 algorithms for authentication and A5 algorithms were used in the process of sending information.But the security system using this algorithm, found weaknesses that allow data tapping or customer identity fraud. While CDMA offers aspects of network security by developing encryption algorithms.For encryption techniques used Rijndael algorithm is safe and very fast. A3 and A8 algorithms can recognize the customer's identity well, and the A5 algorithm can transmit the accuracy of information between MS and BTS.

The Application of RAKE Receiving Technology in the Underwater SS Communication

In recent years, the strategic significance of the oceans is growing as well as its research and development needs. The underwater wireless communication is becoming more and more important. The underwater acoustic communication is one of the few mediums which can conduct the underwater transmission over a long distance, and the multipath effect is the major obstacle of affecting the systems high speed and high reliability. The characteristics of underwater acoustic fading and coherent multi-path channel are studied, and the model of underwater acoustic spreading spectrum (SS) communication system is established. The affect of coding technique on the systems performance are analyzed in detail. The improved RAKE receiving technical solution is put forward, whose simulation analysis and data in different combining ways are given. It is proved that the scheme can better solve the problem of multipath interference in underwater acoustic transmission.

Encryption of Analog and Digital signals through Synchronized Chaotic Systems

Chaos is characterized by aperiodic, wideband, random-like, and ergodicity. Chaotic secure communication has become one of the hot topics in nonlinear dynamics since the early 1990s exploiting the technique of chaos synchronization. As distinguished by the type of information being carried, chaos-based communication systems can be categorized into analogy and digital, including four popular techniques such as Chaos Masking, Chaos Shift Keying, Chaos Modulation, and Chaos Spreading Spectrum. In this chapter, the principles of these schemes and their modifications are analyzed by theoretical analysis as well as dynamic simulation. In addition, chaos-based cryptography is a new approach to encrypt information. After analyzing the performances of chaotic sequence and designing an effective chaotic sequence generator, the authors briefly presented the principle of two classes of chaotic encryption schemes, chaotic sequence encryption and chaotic data stream encryption.