Friday, March 20, 2009

GSM, Security of GSM System

Every day millions of people use cellular phones over radio links. With the increasing features, the mobile phone is gradually becoming a handheld computer. In the early 1980’s, when most of the mobile telephone system was analog, the inefficiency in managing the growing demands in a cost-effective manner led to the opening of the door for digital technology (Huynh & Nguyen, 2003). According to Margrave (n.d), “With the older analog-based cellular telephone systems such as the Advanced Mobile Phone System (AMPS) and the Total Access Communication System (TACS)”, cellular fraud is extensive. It’s very simple for a radio hobbyist to tune in and hear cellular telephone conversations since without encryption, the voice and user data of the subscriber is sent to the network (Peng, 2000). Margrave (n.d) states that apart from this, cellular fraud can be committed by using complex equipment to receive the Electronic Serial Number so as to clone another mobile phone and place calls with that. To counteract the aforementioned cellular fraud and to make mobile phone traffic secure to a certain extent, GSM (Global System for Mobile communication or Group Special Mobile) is one of the many solutions now out there. According to GSM-tutorials, formed in 1982, GSM is a worldwide accepted standard for digital cellular communication. GSM operates in the 900MHz, 1800MHz, or 1900Mhz frequency bands by “digitizing and compressing data and then sending it down a channel with two other streams of user data, each in its own time slot.” GSM provides a secure and confidential method of communication.

Security provided by GSM

The limitation of security in cellular communication is a result of the fact that all cellular communication is sent over the air, which then gives rise to threats from eavesdroppers with suitable receivers. Keeping this in account, security controls were integrated into GSM to make the system as secure as public switched telephone networks. The security functions are:

1. Anonymity: It implies that it is not simple and easy to track the user of the system. According to Srinivas (2001), when a new GSM subscriber switches on his/her phone for the first time, its International Mobile Subscriber Identity (IMSI), i.e. real identity is used and a Temporary Mobile Subscriber Identity (TMSI) is issued to the subscriber, which from that time forward is always used. Use of this TMSI, prevents the recognition of a GSM user by the potential eavesdropper.

2. Authentication: It checks the identity of the holder of the smart card and then decides whether the mobile station is allowed on a particular network. The authentication by the network is done by a response and challenge method. A random 128-bit number (RAND) is generated by the network and sent to the mobile. The mobile uses this RAND as an input and through A3 algorithm using a secret key Ki (128 bits) assigned to that mobile, encrypts the RAND and sends the signed response (SRES-32 bits) back. Network performs the same SRES process and compares its value with the response it has received from the mobile so as to check whether the mobile really has the secret key (Margrave, n.d). Authentication becomes successful when the two values of SRES matches which enables the subscriber to join the network. Since every time a new random number is generated, eavesdroppers don’t get any relevant information by listening to the channel. (Srinivas, 2001)

3. User Data and Signalling Protection: Srinivas (2001) states that to protect both user data and signalling, GSM uses a cipher key. After the authentication of the user, the A8 ciphering key generating algorithm (stored in the SIM card) is used. Taking the RAND and Ki as inputs, it results in the ciphering key Kc which is sent through. To encipher or decipher the data, this Kc (54 bits) is used with the A5 ciphering algorithm. This algorithm is contained within the hardware of the mobile phone so as to encrypt and decrypt the data while roaming.
Algorithms used to make mobile traffic secure

Authentication Algorithm A3: One way function, A3 is an operator-dependent stream cipher. To compute the output SRES by using A3 is easy but it is very difficult to discover the input (RAND and Ki) from the output. To cover the issue of international roaming, it was mandatory that each operator may choose to use A3 independently. The basis of GSM’s security is to keep Ki secret (Srinivas, 2001)

Ciphering Algorithm A5: In recent times, many series of A5 exists but the most common ones are A5/0(unencrypted), A5/1 and A5/2. Because of the export regulations of encryption technologies there is the existence of a series of A5 algorithms (Brookson, 1994).

A8 (Ciphering Key Generating Algorithm): Like A3, it is also operator-dependent. Most providers combine A3 and A8 algorithms into a single hash function known as COMP128. The COMP128 creates KC and SRES, in a single instance (Huynh & Nguyen, 2003).

GSM security flaws

  • Security by obscurity. According to (Li, Chen & Ma) some people asserts that since the GSM algorithms are not publicized so it is not a secure system. “Most security analysts believe any system that is not subject to the scrutiny of the world’s best minds can’t be as secure.” For instance, A5 was never made public, only its description is divulged as part of the GSM specification.
  • Another limitation of GSM is that although all communication between the Mobile station and the Base transceiver station are encrypted, in the fixed network all the communication and signalling is not protected as it is transmitted in plain text most of the time (Li, Chen & Ma).
  • One more problem is that it is hard to upgrade the cryptographic mechanisms timely.
  • Flaws are present within the GSM algorithms. According to Quirke (2004) “ A5/2 is a deliberately weakened version of A5/1, since A5/2 can be cracked on the order of about 216”.

Security breaches

Time to time, people have tried to decode GSM algorithms. For instance, according to Issac press release (1998) in April 1998, the SDA (Smartcard Developer Association) along with two U.C Berkeley researchers alleged that they have cracked the COMP128 algorithm, which is stored on the SIM. They claimed that within several hours they were able to deduce the Ki by sending immense numbers of challenges to the authorization module. They also said that out of 64 bits, Kc uses only 54 bits with zeros padding out the other 10, which makes the cipher key purposefully weaker. They felt government interference might be the reason behind this, as this would allow them to monitor conversations. However, they were unable to confirm their assertion since it is illegal to use equipment to carry out such an attack in the US. In reply to this assertion, the GSM alliance stated that since the GSM network allows only one call from any phone number at any one time it is of no relevant use even if a SIM could be cloned. GSM has the ability to detect and shut down duplicate SIM codes found on multiple phones (Business press release, 1998).

According to Srinivas (2001), one of the other claims was made by the ISAAC security research group. They asserted that a fake base station could be built for around $10,000, which would allow a “man-in-the-middle” attack. As a result of this, the real base station can get deluged which would compel a mobile station to connect to the fake station. Consequently, the base station could eavesdrop on the conversation by informing the phone to use A5/0, which is without encryption.

One of the other possible scenarios is of insider attack. In the GSM system, communication is encrypted only between the Mobile station and the Base Transceiver station but within the provider’s network, all signals are transmitted in plain text, which could give a chance for a hacker to step inside (Li, Chen & Ma).

Measures taken to tackle these flaws

According to Quirke (2004), since the emergence of these, attacks, GSM have been revising its standard to add newer technologies to patch up the possible security holes, e.g. GSM1800, HSCSD, GPRS and EDGE. In the last year, two significant patches have been implemented. Firstly, patches for COMP 128-2 and COMP128-3 hash function have been developed to address the security hole with COMP 128 function. COMP128-3 fixes the issue where the remaining 10 bits of the Session Key (Kc) were replaced by zeroes. Secondly, it has been decided that a new A5/3 algorithm, which is created as part of the 3rd Generation Partnership Project (3GPP) will replace the old and weak A5/2. But this replacement would result in releasing new versions of the software and hardware in order to implement this new algorithm and it requires the co-operation of the hardware and software manufacturers.

GSM is coming out of their “security by obscurity” ideology, which is actually a flaw by making their 3GPP algorithms available to security researchers and scientists (Srinivas, 2001).


To provide security for mobile phone traffic is one the goals described in GSM 02.09 specification, GSM has failed in achieving it in past (Quirke, 2004). Until a certain point GSM did provide strong subscriber authentication and over-the-air transmission encryption but different parts of an operator’s network became vulnerable to attacks (Li, Chen, Ma). The reason behind this was the secrecy of designing algorithms and use of weakened algorithms like A5/2 and COMP 128. One of other vulnerability is that of inside attack. In order to achieve its stated goals, GSM is revising its standards and it is bringing in new technologies so as to counteract these security holes. While no human-made technology is perfect, GSM is the most secure, globally accepted, wireless, public standard to date and it can be made more secure by taking appropriate security measures in certain areas.

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Saturday, March 8, 2008

Pre-paid Reliance Connection

The following article lists some simple, informative tips that will help you have a better experience with Pre-paid Reliance Connection.

Truthfully, the only difference between you and Pre-paid Reliance Connection experts is time. If you'll invest a little more time in reading, you'll be that much nearer to expert status when it comes to Pre-paid Reliance Connection.

Reliance has of a customer base of around thirty-five million and it encompasses more than ten thousand and three hundred towns as well as cities in India. Reliance Mobile services have been showered with several honors in its four year journey. In 2003, A C Nielson chose this company as “India's Most Trusted Telecom Brand”. A world record was made by Reliance India when 1 million subscription were made in just ten days, customers availing the “Monsoon Hungama offer”.

A distinct feature of Reliance is that most of their handsets are data-enabled handsets. This facilitates in the access of Java applications on the Reliance Mobile World. Pre-paid Reliance Connection is offered along with Post-paid Reliance Connection to the subscribers of Reliance. Reliance is introducing several customer friendly plans for those who have or want Pre-paid Reliance Connections.

Pre-paid Reliance Connection is accompanied with many schemes. The latest one is the scheme of offering up to 20 free recharge coupons with new handsets, along with Pre-paid Reliance Connection. The effectiveness of this scheme lies in the fact that the handset price works out to as lowly as Rs.20.

Reliance is offering Motorola C131 for Rs. 3,500 and the ten recharge cards are of the value of Rs. 3,240. Thus, the total price works out to Rs.260. Likewise with LG RD 2030 and Nokia 2280 which costs Rs.6,500, Reliance is giving 20 recharge cards which amounts to Rs. 6,480. The net price works out to Rs.20 only.

RIM packages can be availed at a low price of just Rs. 1,500. Reliance to Reliance unlimited talk time is a great hit among Reliance subscribers. Many have opted for lifetime connection too. There are low ranges of recharge cards and also of the value of Rs. 1,080 ( Rs. 850 talk time) and Rs. 540 ( Rs. 375 talk time).

Reliance is surely making a lot of their customers smile with their efficiency and cost effective services through Pre-paid Reliance Connection.

Reliance offers both pre-paid and post-paid mobile services to its million of subscribers across the country of India

Is there really any information about Pre-paid Reliance Connection that is nonessential? We all see things from different angles, so something relatively insignificant to one may be crucial to another.

Monday, February 18, 2008

Funny SMS

This interesting article addresses some of the key issues regarding SMS. A careful reading of this material could make a big difference in how you think about SMS.

The more authentic information about SMS you know, the more likely people are to consider you a SMS expert. Read on for even more SMS facts that you can share.

One of the most potent Features of Mobile Phones, the SMS is an integral part of communication. One of the most popular and fast mediums of establishing a contact or mediating an important information, the Short Message Service or more popularly termed SMS. SMS is both common and very well known among the young as well as the adults. In the most colloquial term, SMS often refers to text messaging and sending short messages to and from mobile phones. In the stricter technical terms, SMS actually implies a GSM technology by which a message of up to 160 characters can be sent.

Although most SMS messages are mobile-to-mobile text messages, the standard ones support other types of broadcast messaging as well. Apart from the GSM mobile handsets SMS is supported in other technologies as well. An important value added service provided by the Mobile service providers, to their customers was the idea of adding text messaging or SMS. The addition of text messages or SMS to the services of mobile users started mainly from the early 1980s. SMS was thought of as a means which provides alerts to the individual mobile user like that of a deposited voice mail. But others had more sophisticated applications in their minds, such as telemetry.

The fastest and cheapest way to communicate, the SMS is mediated from the Message Delivery Center of the service provider. However, not all text messaging systems use SMS, there are some notable alternate implementations too which include J-Phone's SkyMail and NTT Docomo's Short Mail, both rampant in Japan.

One of the fastest growing industries within the fold of the Mobile Industry, the SMS industry is worth almost 80 billion dollars across the globe. A model adopted by industries like banking and finance, entertainment etc all service providers across the globe reap golden harvest out of the SMS services.

The day will come when you can use something you read about here to have a beneficial impact. Then you'll be glad you took the time to learn more about SMS.

Thursday, February 7, 2008

Nokia E51 Camera Phone

Have you ever wondered what exactly is up with Nokia E51 Camera Phone? This informative report can give you an insight into everything you've ever wanted to know about Nokia E51 Camera Phone.

If your Nokia E51 Camera Phone facts are out-of-date, how will that affect your actions and decisions? Make certain you don't let important Nokia E51 Camera Phone information slip by you.

Nokia E51 is a dual band mobile phone from the house of Nokia Corporation. It belongs to the recently launched E series cell phones of Nokia. A Nokia E51 camera phone is different from its predecessors in many ways. This smart looking device extends to the consumers a number of niche benefits unlike anything before. The elegant brown frame adds sense to the usage of mobile telephony. With a Nokia E51 at your disposal, you can enjoy some neat features including quicker access to the service provider, more well-structured application facilities and seamless connectivity.
The E series Nokia phones had to live up to the expectations of the subscribers who were used to the famous N series. Needless to mention, the challenge was enormous, but the E series fulfilled the hype ever so smartly by coming up with Nokia E51 camera phone. Among all the Nokia phones with camera, the Nokia E51 camera phone is truly one of its kind. This handset abounds in all the smartphone features and at the same time, churns out something more.

Customer satisfaction index shows that a Nokia E series device has turned out to be a hot favorite among consumers of all ages. It is an all-round tool, made to ease up voice and data connectivity across the GSM networks all around the world. Nokia E51 camera phones are manufactured specifically for the business professionals who are always on the lookout for some handy device, tailormade to suit their requirements of meeting new clients and stay connected to them all the time. Since time management has assumed a great significance nowadays, modern day professionals do not have the luxury to use complicated mobile phones.

They prefer simple, one-touch devices that let them connect with friends and colleagues in a real-time environment. The reliability factor of Nokia E51 camera phone is another thing which has made it popular among the buyers. You can easily take snapshots, record videos, send MMS or emails to your near and dear ones. Unlike other Nokia phones, Nokia E51 camera phone offers prospective business value to end users. It is comprehensively integrated with corporate telephony systems (PBX) via Nokia Mobile Unified Communications solutions such as Nokia Intellisync Call Connect fot Alcatel and Nokia Intellisync Call Connect for Cisco. These applications provide full-proof and reliable fixed phone calling features, including call hold, extension dialing, call conferencing and call transfer facilities. You can access to a plethora of customized services at a single go. By availing of these features, major companies can also lessen their international dialing charges by routing the calls through corporate IP networks.

The 2.0 megapixel inbuilt camera is featured with 4x digital zoom. Maximum user storage space is 130 MB. External memory cards up to 4 GB can be inserted into a Nokia E51.

I hope that reading the above information was both enjoyable and educational for you. Your learning process should be ongoing--the more you understand about any subject, the more you will be able to share with others.

Sunday, February 3, 2008

Mobile Phone Batteries-Golden rules for longer battery life

Choosing mobile phone batteries is not as simple a task as it sounds. Mobile phone manufacturers have to keep a lot of factors in mind while choosing mobile phone batteries depending on the location, humidity, weight, size, backup, expected lifecycle of the product, commercial feasibility and environmental impact. There are many different types of mobile phone batteries available from various manufacturers.

The Nickel Cadmium battery is the oldest type, the same as the ones used in cordless phones. There were very cheap but had a pronounced ‘memory effect’ where the battery looses efficiency if not fully discharged and then charged. The Nickel Metal Hydride battery is a better version than the Nickel Cadmium battery and has a lesser ‘memory effect’. The Lithium Ion battery is the most advanced batteries commercially available today. They are free of the ‘memory effect’ and provide a much smaller size, lighter weight with a better talk-time and stand-by time. Comparatively more expensive to manufacture, these batteries are still affordable and extensively used. The Lithium Polymer is the next generation batteries which are rare and very expensive.

There are a few things which you can do to increase the efficiency of your mobile phone batteries. Remove all unnecessary sound effects like key pad tone, reduce the use of vibration alert as it consumes a lot of energy, adjust the timer for the backlight and always use digital mode when in areas where digital signalling is available instead of keeping it at dual mode.

There are three golden rules to protect your mobile phone batteries. Dropping your mobile phone batteries can reduce its efficiency drastically. Mobile phones should be switched off before removing the battery. Avoid high temperature and direct sunlight. These three golden rules are the most basic protection you need to provide in order to safeguard your mobile phone batteries.

Friday, February 1, 2008

Motorola Mobile Phone Models

The following article presents the very latest information on Motorola Mobile Phone Models. If you have a particular interest in Motorola Mobile Phone Models, then this informative article is required reading.

Now that we've covered those aspects of Motorola Mobile Phone Models, let's turn to some of the other factors that need to be considered.

Today, it is difficult to trace a person who does not own a mobile phone. The top five mobile phone manufacturers are available in nearly 75% of the countries of the world. Among the top five mobile phone manufacturers, is Motorola. Motorola mobile phone models are available all over the world. Motorola offers excellent customer service, you can either write to the company's online support center, or you can go to the support center nearest to your locality. Motorola also provides various downloadable softwares for its users, most of these are available for free.

Motorola manufactures mobile phones to suit consumers from different backgrounds. The list is huge. Here we will mention a few of the popular Motorola mobile phone models.

MOTOKRZR- The phone kit comes with a one year warranty. To name a few of its cool features, the phone has bluetooth technology, music player, a 2 MP camera, and comes in a variety of attractive colors like blue, gold, and red. This is an unlocked phone. This means that it works with all GSM carriers.

MOTOSLVR- It works with all GSM carriers. Its phone book can store upto 500 contacts. It has bluetooth wireless technology, and comes in a sleek, silver and black colors, to name just a few of its cool features.

MOTORIZR Z3- This sleek Motorola mobile phone sports cool features like bluetooth technology, 2 MP camera, digital camera, EMS, SMS, MMS, E-Mail, to name only a few.

Other Motorola mobile phone models are MOTORAZR 2, MOTO Q , Motorola C139, Motorola V235 , Motorola V197 to name just a handful.

If you've picked some pointers about Motorola Mobile Phone Models that you can put into action, then by all means, do so. You won't really be able to gain any benefits from your new knowledge if you don't use it.

Thursday, January 31, 2008

Nokia 6301-New Nokia Phone Models

Those of you not familiar with the latest on Nokia 6301,you will get full information on new nokia phone models nokia 6301.

Have you already planned to attribute your set with the term “back dated” then consider to avail one of the new Nokia phone models like Nokia 6301. Changing your mobile set on a frequent basis has become quite a trend in the communication world. One thing about Nokia is that it has already made a mark in the communication world. While the old Nokia phone models did have some exciting features , with the passage of time the gradual change in the features did take place. This resulted in manufacturing some of the best Nokia phones. One of the most popular Nokia phone set is Nokia 6301. So before you of purchasing Nokia phones you can definitely consider to explore the wide variety of Nokia phones.
You can consider purchasing Nokia 6301 that has a smooth and elegantly designed body. Also the features are extremely user friendly having all the best facilities that can be availed by the customers. The monoblock design with a very sleek elegantly designed back and front is simply breath taking. Owning Nokia 6301 is nothing but owning a piece of art. Nokia 6301 measures about 106.4 mm in length and 43.6mm in width. The thickness measuring to about 13.1 mm and the total weight of the model is 93g. Also you cannot simply afford to miss the UMA design that gives you access to GSM and GRPS mobile services over Wlan. With UMA design, Nokia offers you with invincible coverage with complete mobility coverage, all this at a lucrative price tag.

Some of the key features of Nokia 6301 includes the following:

* The UMA availability definitely offers to the facility to make call from from home, office or other operator spots that are very much affordable and or free.
* Access to fast service with UMA facilities.
* There is a mega pixel camera which is provided with 8x digital zoom and full screen viewfinder.
* FM radio and Stereo MP3 player are two of the other features.
* Streaming of Video 3GPP.

Besides the key features, Nokia 6301 has some music, multimedia and gaming features as well, these are follows:

* Stereo MP3 player and FM radio, both integrated. .
* Application program comprising of Visual radio.
* Playing MP3 music files, Midi, AAC, AAC+, enhanced AAC+, WMA music files.
* News or entertainment made possible with the presence of Video 3GPP streaming
* Macromedia Flash Lite 2.0 option, Nokia Sensor,Nokia Visual radio,3D snake, pre installed Java games and applications.

Take a look at some of the accessories that is being offered with Nokia 6301 model.

* Nokia Connectivity Cable DKE-2: this is one of the mos attractive accessories that connects your compatible Nokia device to the PC, catering to the need of enabling data transfer, also helping in the synchronization of your calender, contacts, notes, to do list, and also many other features.
* Nokia Blue tooth Display Car Kit CK-15W: this has 2.2 '' display with excellent Blue tooth connectivity and audio quality, a great companion for your car.
* Nokia 2 GB micro SD Card MU-37: this particular accessory of Nokia phones provides about 2GB of removal storage and also increases the memory availability for data, which can either music software applications.

It never hurts to be well-informed with the latest on Nokia 6301. Compare what you've learned here to future articles so that you can stay alert to changes in the area of Nokia 6301.