GSM Security

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The Subscriber Identity Module (SIM) is a small smart card which contains both programming and information. The A3 and A8 algorithms are implemented in the Subscriber Identity Module (SIM). Subscriber information, such as the IMSI (International Mobile Subscriber Identity), is stored in the Subscriber Identity Module (SIM). The Subscriber Identity...
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How Do I Use CallerID?

Posted by on September 1, 2010
Calling Line Identification Presentation (CLIP) affects your reception of CallerID data: Activate Incoming (CLIP) * 30 # SEND Deactivate Incoming (CLIP) # 30 # SEND Verify Incoming (CLIP) *# 30 # SEND Calling Line Identification Restriction (CLIR) affects your transmission of CallerID data: Activate Outgoing (CLIR) * 31 # SEND Deactivate...
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How Do I change my PIN and PUK?

Posted by on September 1, 2010
Change SIM Card PIN ** 04 * old PIN * new PIN * new PIN # Change SIM Card PIN2 ** 042 * old PIN2 * new PIN2 *new PIN2 # Change SIM Card PUK ** 05 * old PUK * new PUK * new PUK # Change SIM Card PUK2 ** 052 * old PUK2 * new PUK2 * new PUK2 # Note: These codes only work on some mobile stations offered by some providers. VN:F [1.9.22_1171]please...
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What Are the PIN and PUK?

Posted by on September 1, 2010
PIN (Personal Identity Number) is a 4-8 digit access code which can be used to secure your telephone from use. PIN2 (Personal Identity Number 2) is a 4-8 digit access code which can be used to access the priority number memory and cost of calls. The PUK (Personal Unblocking Key) and PUK2 are used to unlock the PIN and PIN 2 codes respectively if...
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What is a TIMSI?

Posted by on September 1, 2010
The TIMSI (Temporary IMSI) is a pseudo-random number generated from the IMSI (International Mobile Subscriber Identity) number. The TIMSI is utilized in order to remove the need to transmit the IMSI over-the-air. This helps to keep the IMSI more secure. To track a GSM user via the IMSI/TIMSI, an eavesdropper must intercept the GSM network communication...
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What is an IMSI?

Posted by on September 1, 2010
The IMSI (International Mobile Subscriber Identity) is a unique 15-digit code used to identify an individual user on a GSM network. The IMSI consists of three components: Mobile Country Code (MCC) Mobile Network Code (MNC) Mobile Subscriber Identity Number (MSIN) The IMSI is stored in the Subscriber Identity Module (SIM). VN:F [1.9.22_1171]please...
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What is an IMEI?

Posted by on September 1, 2010
The IMEI (International Mobile Equipment Identity) is a unique 17 or 15 digit code used to identify an individual mobile station to a GSM or UMTS network. The IMEI number provides an important function; it uniquely identifies a specific mobile phone being used on a mobile network. The IMEI is a useful tool to prevent a stolen handset from accessing...
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What Are locking and unlocking?

Posted by on September 1, 2010
Most GSM Mobile Stations (MS) are sold to be used on a specific GSM network. The Mobile Stations are “locked” to only accept a Subscriber Identity Module (SIM) from the GSM carrier that sold the Mobile Station. There are several situations where you would want to unlock your Mobile Station. For example, you might wish to switch GSM...
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Have the A5 algorithms been broken?

Posted by on September 1, 2010
Alex Biryukov, Adi Shamir and David Wagner showed that they can find the A5/1 key in less than a second on a single PC with 128 MB RAM and two 73 GB hard disks, by analyzing the output of the A5/1 algorithm in the first two minutes of the conversation. Ian Goldberg and David Wagner of the University of California at Berkeley published an analysis...
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Most GSM providers use a version of COMP128 for both the A3 authentication algorithm and the A8 key generation algorithm. Ian Goldberg and David Wagner of the University of California at Berkeley demonstrated that all A8 implementations they looked at, including the few that did not use COMP128, were deliberately weakened. The A8 algorithm takes...
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