07-07-2012, 03:53 PM
GSM SECURITY AND ENCRYPTION
[attachment=27171]
INTRODUCTION
Global system for mobile communication (GSM) is a digital, mobile, radio standard developed for mobile, wireless, voice communications and it designed by standardization committees from major European telecommunication operators and manufactures. The GSM system provides a common set of compatible services and capabilities to all mobile users across worldwide customers. The GSM is a fully digital system, allowing both speech and data services and allowing roaming across networks and countries. The motivation for security in GSM systems are to secure conversation and signalling data from interception as well as to prevent cellular telephones problems.GSM security is addressed in two aspects authentication and encryption. Authentication avoids fraudulent access of a cloned MS. Encryption avoids unauthorised listening. To intercept and reconstruct this signal would require more highly specialized and expensive equipment than a police scanner to perform the reception, synchronization, and decoding of the signal. In addition, the authentication and encryption capabilities discussed in this paper ensure the security of GSM cellular telephone conversations and subscriber identification credentials against even the determined eavesdropper.
THE MAIN GOALS OF GSM SECURITY AND ENCRYPTION ARE-
• Confidentiality and Anonymity on the radio path.
• Strong client authentication to protect the operator against the billing fraud.
• Prevention of operators from compromising each other security.
• Improved spectrum efficiency.
• International roaming.
• Low-cost mobile sets and base stations (BSs).
• High-quality speech.
GSM OVERVIEW
GSM: Global system for mobile (GSM) is a second generation cellular system standard that developed to solve the fragmentation problems of the first cellular system. GSM stands for Global System for Mobile Communication and is an open, digital cellular technology used for transmitting mobile voice and data services. The GSM emerged from the idea of cell-based mobile radio systems at Bell Laboratories in the early 1970s.GSM was first introduced into the European market in 1991.The GSM standard is the most widely accepted standard and is implemented globally. The GSM is a circuit-switched system that divides each 200 kHz channel into eight 25 kHz time-slots. GSM operates in the 900MHz and 1.8GHz bands in Europe and the 1.9GHz and 850MHz bands in the US. The GSM makes use of narrowband Time Division Multiple Access (TDMA) technique for transmitting signals.
GSM ARCHITECTURE:
GSM services follow ISDN guidelines and classified as either tele-service or data services. Services include standard mobile telephony, mobile-originated traffic, computer to computer communication and packet-switched traffic. The GSM system consists of a number of separate entities. The entities are connected through interfaces with their own names according to the specifications.
CALLING PROCEDURE IN GSM
Network components of GSM are described below:
3.1 MOBILE STATION (MS) - This is the starting point of a mobile wireless network. The MS can be two interconnected physical devices (MT and TE) with a point-to-point interface or a single device with both functions integrated. When a subscriber uses the MS to make a call in the network, the MS transmits the call request to the base transceiver station (BTS). The BTS is responsible for establishing the link to the MS and for modulating and demodulating radio signals between the MS and the BTS.
3.2 BASE STATION CONTROLLER (BTC) - It is the controlling component of the radio network, and it manages the BTSs. The BSC reserves radio frequencies for communications and handles the handoff between BTSs when an MS roams from one cell to another. The BSC is responsible for paging the MS for incoming calls.
3.3 BASE STATION SUBSYSTEM (BSS) - It is controlled by a BSC. The BSS performs the necessary functions for monitoring radio connections to the MS, coding and decoding voice, and rate adaptation to and from the wireless network. A BSS can contain several BTSs.
3.4 MOBILE SWITCHING CENTRE (MSC) - The mobile switching centre (MSC) is a digital ISDN switch that sets up connections to other MSCs and to the BSCs. The MSCs form the wired (fixed) backbone of a GSM network and can switch calls to the public switched telecommunications network (PSTN). An MSC can connect to a large number of BSCs.
[attachment=27171]
INTRODUCTION
Global system for mobile communication (GSM) is a digital, mobile, radio standard developed for mobile, wireless, voice communications and it designed by standardization committees from major European telecommunication operators and manufactures. The GSM system provides a common set of compatible services and capabilities to all mobile users across worldwide customers. The GSM is a fully digital system, allowing both speech and data services and allowing roaming across networks and countries. The motivation for security in GSM systems are to secure conversation and signalling data from interception as well as to prevent cellular telephones problems.GSM security is addressed in two aspects authentication and encryption. Authentication avoids fraudulent access of a cloned MS. Encryption avoids unauthorised listening. To intercept and reconstruct this signal would require more highly specialized and expensive equipment than a police scanner to perform the reception, synchronization, and decoding of the signal. In addition, the authentication and encryption capabilities discussed in this paper ensure the security of GSM cellular telephone conversations and subscriber identification credentials against even the determined eavesdropper.
THE MAIN GOALS OF GSM SECURITY AND ENCRYPTION ARE-
• Confidentiality and Anonymity on the radio path.
• Strong client authentication to protect the operator against the billing fraud.
• Prevention of operators from compromising each other security.
• Improved spectrum efficiency.
• International roaming.
• Low-cost mobile sets and base stations (BSs).
• High-quality speech.
GSM OVERVIEW
GSM: Global system for mobile (GSM) is a second generation cellular system standard that developed to solve the fragmentation problems of the first cellular system. GSM stands for Global System for Mobile Communication and is an open, digital cellular technology used for transmitting mobile voice and data services. The GSM emerged from the idea of cell-based mobile radio systems at Bell Laboratories in the early 1970s.GSM was first introduced into the European market in 1991.The GSM standard is the most widely accepted standard and is implemented globally. The GSM is a circuit-switched system that divides each 200 kHz channel into eight 25 kHz time-slots. GSM operates in the 900MHz and 1.8GHz bands in Europe and the 1.9GHz and 850MHz bands in the US. The GSM makes use of narrowband Time Division Multiple Access (TDMA) technique for transmitting signals.
GSM ARCHITECTURE:
GSM services follow ISDN guidelines and classified as either tele-service or data services. Services include standard mobile telephony, mobile-originated traffic, computer to computer communication and packet-switched traffic. The GSM system consists of a number of separate entities. The entities are connected through interfaces with their own names according to the specifications.
CALLING PROCEDURE IN GSM
Network components of GSM are described below:
3.1 MOBILE STATION (MS) - This is the starting point of a mobile wireless network. The MS can be two interconnected physical devices (MT and TE) with a point-to-point interface or a single device with both functions integrated. When a subscriber uses the MS to make a call in the network, the MS transmits the call request to the base transceiver station (BTS). The BTS is responsible for establishing the link to the MS and for modulating and demodulating radio signals between the MS and the BTS.
3.2 BASE STATION CONTROLLER (BTC) - It is the controlling component of the radio network, and it manages the BTSs. The BSC reserves radio frequencies for communications and handles the handoff between BTSs when an MS roams from one cell to another. The BSC is responsible for paging the MS for incoming calls.
3.3 BASE STATION SUBSYSTEM (BSS) - It is controlled by a BSC. The BSS performs the necessary functions for monitoring radio connections to the MS, coding and decoding voice, and rate adaptation to and from the wireless network. A BSS can contain several BTSs.
3.4 MOBILE SWITCHING CENTRE (MSC) - The mobile switching centre (MSC) is a digital ISDN switch that sets up connections to other MSCs and to the BSCs. The MSCs form the wired (fixed) backbone of a GSM network and can switch calls to the public switched telecommunications network (PSTN). An MSC can connect to a large number of BSCs.