یک اولویت برای WSN در محیط همه جا حاضر: الزامات امنیتی چند رسانه ای A priority for WSN in ubiquitous environment: multimedia security requirements

1 Introduction As interest in ubiquitous environment construction is growing, Radio Frequency Identification (RFID) technique and Wireless Sensor Networks (WSN) [28] are also attracting a lot of attention as core technologies. With the rapid expansion of the ubiquitous environment, in the near future WSNs will be a familiar and vital element in our daily lives. Under the humancentric ubiquitous environments WSNs will collect and transmit a variety of personal data such as our tastes, living patterns, experiences and so on. Therefore, to protect the private data of users, security requirements for WSNs are assuming more importance and the need for review and study of the security of the WSN system will be critical factors in developing WSN applications. Moreover, multimedia data has always huge size and relate with lots of information around us, so it is very important to consider the multimedia security requirements in WSN system. A WSN is a collection of nodes equipped with processing capability such as one or more microcontrollers, CPUs or DSP chips organized into a cooperative network [12]. Each node may contain multiple types of memory for program, data, a RF transceiver usually with a single omni directional antenna, a power source, and accommodate various sensors and actuators. After being deployed, these nodes communicate wireless method and organize in an ad hoc network [29]. As their applications increase in a variety of fields, these systems are revolutionizing our daily life and workspaces. WSNs have already been applied to a variety of fields in our living environment. For example,an environmental monitoring system monitors air, soil and water and perform condition-based maintenance and a habitat monitoring system tracks plant and animal species population and behavior. Also, WSNs have been applied to seismic detection, military surveillance, inventory tracking, smart spaces etc. In fact, due to the pervasive nature of micro-sensors, sensor networks have the ability to change the way I construct complex physical system [34]. Now, as WSNs have become a fundamental element in the humancentric ubiquitous environment, the number and variety of applications will grow. With the rapid growth of WSN applications, the need for security for WSNs becomes vital. However, WSNs must overcome a variety of constraints such as limitations in energy consumption, processing capability, and storage capacity, etc. Many innovative security protocols and techniques have been developed to solve these limitations. Among the many ways to provide security [14], one studied most intensively is cryptography. Deciding the appropriate cryptography method for sensor nodes is fundamental to providing security services in WSNs [26]. The studies about cryptography techniques are useful to protect the data transmitted between the sensor nodes. However, security of an overall software system handling and processing the data transferred and stored from the WSN system is also an important concern and must be considered in designing the WSN system. Because the cryptography techniques are appropriate for the security of the overall software system, suitable security attributes need to be considered and implemented. The data generated presently in WSNs is different from previous data processed by an existing database system. The size of the data may be small but the data is generated more rapidly and in huge amounts. Therefore, the security attributes and their relative priorities are different from general software systems.