Security in Bluetooth

>Abstract: - : - 


As the technology becomes more sophisticated, the need for facile wireless communication has led the human brain to renovate the orthodoxy bottlenecked conventions being used. Computing will inevitably be indispensable and ubiquitous – a scenario that has no place for wires. Bluetooth provides several irksome issues that have plagued implementation of wireless technology handling both data and voice transmissions, allowing such capabilities as a mobile hands-free head set for voice calls and print-to-fax, laptop and cell phone address book applications. More than just a replacement for Proprietary cables, Blue tooth wireless technology provides a Universal bridge to existing data networks LAN’s, mobile phone network and the internet for a host of home applications and portable hand-held interfaces.

                    Bluetooth enabled electronic devices connect and communicate wirelessly via short-range, ad-hoc networks called ‘Piconets’. Each unit can simultaneously communicate with up to seven other units in a piconet. These piconets are established dynamically and automatically as blue tooth devices enter and leave the radio proximity. To replace messy wires, make information transfer automatic without synchronization cradles and introduced many applications Bluetooth excels at connecting devices irrespective of their locations and can even talk through walls.

Introduction

 

What is Bluetooth?

                      Bluetooth is the global defector standard for wireless connectivity based on low-cost, short-range radio link that resides on a micro chip. Bluetooth wireless technology is a system solution comprising hardware, software and Interoperability requirements.  Bluetooth is a standard for a small, cheap radio chip to be plugged in to computers, printers, mobile phones etc. Bluetooth wireless technology eliminates the need for numerous, often   Proprietary, cable attachments for connection of practically any kind of communication device.

Concept behind Bluetooth

                            The basic concept behind the Bluetooth is to provide a universal short range wireless capability. It operates in free Industrial Scientific Medical(ISM) band from 2.400 GHz to 2.483GHz, available globally for unlicensed low-power uses. Two Bluetooth devices within 10m of each other can share up to 720kbps of capability. It has the transmission power of 1mW.  Bluetooth is intended to support an open-ended list of applications, including data, audio, graphics and even video. For e.g. Audio devices can include headsets, cordless and standard phones, home stereos, and digital MP3 players. 

 

Security Architecture

                When wireless connection is used in communication the eavestroping is much easier. That’s why security and encryption is very important with Bluetooth devices. BT specifies security on several levels from base band to service level. Base band uses SAFER+ algorithms for security purposes. BT’s encryption engine requires master nodes BT address its slot clock and secret key i.e. that is shared by all the participant devices.    

      

Architecture overview

 The ‘core protocols’ form a five-layer stack consisting of the following elements:

•       Radio: Specifies details of the air interface, including frequency, the use of frequency hopping, modulation scheme, and transmit power.

•       Baseband: Concerned with connection establishment within a Pico net, addressing, packet format, timing, and power control.

•       Link manager: responsible for link setup between Bluetooth devices and on going link management. This includes security aspects such as authentication and encryption, plus the control and negotiation of base band packet sizes.

•       Logical link control and adaptation protocol (L2CAP): adapts upper-layer protocols to the base band layer.L2CAP provides both connectionless and connection-oriented services.

•       Services discovery protocol (SDP): is device information, services, and the characteristics of the services can be queried to enable the establishment of a connection between two or more Bluetooth devices.

Network Topology

Bluetooth devices are generally organized into groups of two to eight devices called Piconets, consisting of a single master device and one or more slave devices. A device may additionally belong to more than one piconet, either as a slave in both or as a master of one piconet and a slave in another. These bridge devices effectively connect piconets into a scatternet. A diagram of a Bluetooth scatternet is shown in figure above. Bluetooth operates in the unlicensed ISM frequency band that is generally cluttered with signals from other devices-garage door openers, baby monitors, and microwave ovens, to name just a few. This pattern, moving through 1,600 different frequencies per second, is unique to the particular piconet. Each frequency “hop” is a time slot during which data packets are transferred. A packet may actually span up to five time slots, in which case the frequency remains constant for the duration of that transfer.

Conclusion 

            Designed as a cable-replacement technology, Bluetooth wireless technology is well suited to the connectivity requirements of WPANs composed of portable computers, PDAs, mobile phones, and printers. It is ideally suited to mobile devices (particularly PDAs) because of their small size, low power requirements, and applications (mobile phone wireless WAN connectivity, peer-to-peer business card or calendar exchange, and wireless synchronization). As the technology matures, implementations increase, and native operating system support becomes available, interoperability and ease-of-use issues should diminish. Industries are committed to provide Bluetooth solutions that meet customer needs, have been thoroughly tested for compliance, and coexist with Wi-Fi networks. The possibility for new applications is very exciting with this versatile technology. The Bluetooth communication device will thus be a small, low powered radio in a chip that will talk to other Bluetooth enabled products. Bluetooth has been designed to solve a no. of connectivity problems experienced by the mobile workers & consumers. Thus, this technology helps make the electronic devices more user-friendly.