International Journal of Computer Applications (0975 – 8887) Volume 49– No.10, July 2012 29 Bit Shuffling Query Tree Algorithm for Secure Communication in RFID Networks Nivedita Das Dept. of Information Technology Calcutta UniversityKolkata, India Indrajit Bhattacharya Dept. of Computer Application Kalyani Govt. Engineering College Kalyani, India ABSTRACT RFID uses radio frequency waves to track and identify objects. RFID system consists of tags and readers. Passive RFID tags are more popular now days due to its simpler circuitry, lower weight and lower cost. Generally passive tags are attached with an object for unique identification. A tag contains information about the particular product, to which it is attached. RFID reader is used to interrogate the tag to get the identity of the product attached with. RFID has numerous applications such as inventory management, asset tracking, library management etc. One of the major problems with RFID system is that whenever a reader interrogates a tag, all the tags residing in the read zone of the reader responds to the reader, which results in a collision at the reader‟s side. Thus makes it impossible to read the tags in time. To minimize the problem of collision at the reader side several anti collision algorithms has been proposed, but none of the algorithm concerns about the security aspect. Security is another major problem of RFID system. RFID tag discloses its identity to any reader which interrogates the tag, so any illegitimate reader can obtain the information contained in the tag. Now a day‟s situation is much worse because not only unique identification number but also user information such as name, address, phone number and other relevant information‟s of consumer are stored in the tag. There are different manufacturers of tags who provide tags with 1kb memory, which is large enough to store such kind of consumer information without pointing to backend database. In such cases security concern is much more as eavesdropping may lead to disclose some personal data, which is a big threat for consumer. Implementing cryptographic algorithm is not a feasible solution for the RFID system, as this may result in complex circuitry, and which in turn may raise size and cost of the passive tags. Here in this paper we have combined both the problem of collision and security together to find a suitable solution which solves both the problems. Taking into consideration of simpler circuitry and lower price of passive tags, here we propose a solution which modifies existing anti collision protocol to make it secure so that any illegitimate reader cannot read the information contained in the tag thus protecting tags from malicious reading. General Terms RFID secure singulation protocol. Keywords Secure anti collision protocol, Secure Tree based algorithm. 1. INTRODUCTION The abbreviation RFID stands for “Radio Frequency Identification”. It is a contactless automatic, without line -of- sight (LOS), low-power and low-cost wireless communication technology that provides automatic identification and data collection. This technology uses radio waves to transfer data from an electronic tag, called RFID tag, attached to an object, through a reader for the purpose of identifying and tracking the object. RFID and barcodes has several common properties with respect to automatic identification perspective. It has several advantages compared to any other identification technique, like it provides greater speeds, data encryption, covers greater distances; it is more immune to surrounding environment, it also reduces human involvement in the identifying process. RFID is regarded as a substitute technology for the barcode which is currently used in distribution and circulation fields and financial services. RFID technology depends on communication between reader and tag. The read range of the reader depends on the operational frequency of the reader [1]. RFID becoming the most popular identification technology day by day because of its low price and simple circuit design. RFID has a numerous number of applications, such as tracking and managing inventory, people, assets, domestic animals, library books etc. Health industry also used RFID technology to identify medicines, which are running out of date and should be replaced with a new one. Also in the recent past (2010) social media, announced to tie physical world to the virtual world by using this technology. RFID technology comprises of three components namely tags, readers and data processing sub system. [1] Tags are generally of two types, active and passive. Tags are also known as transponders. Usually tags are attached with an object for unique identification. Passive tags do not contain any battery source. Instead they derive power from reader when interrogated. [2] [2] Readers are also known as transceivers. They are used to interrogate tags using radio frequency waves. The main function of reader is to wake up the passive tags and retrieve information stored in the tags memory. [3] A Data processing subsystem can be application or database, depending on the application. This can be attached with the reader through wireless or wired media. [2]