Proceedings published by International Journal of Computer Applications® (IJCA) International Conference on Computer Communication and Networks CSI- COMNET-2011 24 A Hybrid Encryption Technique to Secure Bluetooth Communication P S Patheja BIST Bhopal Akhilesh A. Waoo BIST Bhopal Sudhir Nagwanshi BIST Bhopal ABSTRACT A proprietary open wireless technology standard for exchanging data over short distances from one device to another is not much secure. As in traditional method of Bluetooth communication between two or more devices a 128-bit symmetric stream cipher called E0 is used which seems to be week under some conditions it may be broken under certain conditions with the time complexity O (2 64 ). To improve security of data we propose a hybrid encryption technique. In this technique we use triple DES for encryption of the key for which we use Tiger algorithm. In Tiger algorithm there is double protection of Data using triple DES and with the help of this algorithm transmission of data will be more secure for exchanging data over short distances from one device to another. Keywords Bluetooth, E0 key stream, hybrid encryption algorithm, data transmission. 1. INTRODUCTION Bluetooth is a high-speed, low-power microwave wireless link technology, which is based on chip that provide a wireless link to connect phones, laptops and other portable equipment together. Bluetooth is used for a short-range radio frequency (RF) technology that operates at 2.4 GHz and is capable of transmitting voice and data from one device to other. The effective range of Bluetooth devices is 32 feet (10 meters). Bluetooth transfers data at the rate of 1 Mbps, which is from three to eight times to the average speed of parallel and serial transmission. It was invented to get rid of wires [1] . Bluetooth is more suited for connecting two point-to-point devices. Security issues arising from Bluetooth are relatively less publicized, possibly due to less critical nature of information at stake - an individual's cell phone data against corporate data thefts and associated hard losses. Nevertheless, with respect to personal privacy and perimeter security, an insecure Bluetooth device or technology can pose serious risk of information compromise. Now let’s explore the categories in which Bluetooth hacking is often classified. This will show how real the issue of security in Bluetooth devices is. Bluetooth hacks are categorized broadly among: Blue Jacking: It is the simplest of the four. The hacker uses it by making an attempt to send a phone contact or business card to another nearby phone. The ‘name' field of the contact can be misused by replacing it with a suggestive text so that the target device reads it as a part of intimation query displayed on its screen. Bluesnarfing: It goes a step further and actually accesses or steals data like messages, calendar, phone book etc., from the target device in an unauthorized manner which includes bypassing the usual paring requirement. Here, the problem is bigger since there have been reports of the tools that use methods such as device address guessing and brute force in order to break-in, even when device is configured as ‘invisible'. The next level of sophistication in Bluetooth hacking is Blue bugging where the victim device is controlled by the attacker who sends commands to perform actions as if having physical access to the device this is a functionality analogous to Trojans. Bluetoothing: Lastly, it is Bluetoothing which typically means social networking in short range, and there is a possibility of harassment from the security point of view. There are programmers for Bluetooth PIN code cracking as well. The encryption algorithm using in Bluetooth encryption process is the E0 stream cipher. However, this algorithm has some shortcomings, The 128-bit E0 stream ciphers can be cracked with the time complexity O(2 64 ) in some cases. So, for most applications which need top priority to confidentiality, the data security is not enough if we are using the traditional E0 Bluetooth Algorithm. In this paper we are introducing the Hybrid Encryption algorithm for solving the current security risks in Bluetooth data transmission, but before that we will discuss on basic Bluetooth Mechanism and also about its disadvantages. 2. OVERVIEW 2.1 Security Mechanism in Bluetooth The Bluetooth defines three security modes: 2.1.1 Safe Mode 1 No safe mode, which has the lowest security level. 2.1.2 Safe Mode 2 Service-oriented security model, which start after the establishment of the channel. 2.1.3 Safe Mode 3 link-oriented security model, which install and initial before communication link is established. Bluetooth system provides safety precautions in the application layer and link layer, and both sides achieve authentication and encryption in the same way. Link layer uses four entities to ensure the safety: 1. 48-bit of the Bluetooth device address, which is global uniqueness decided by the IEEE; 2. The authentication key for entity authentication is 128-bit; 3. The secret key for data encryption is 8 ~ 128-bit;