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Subscriber Identity Module [SIM]

Subscriber Identity Module, or SIM cards are a type of Smart Card used in GSM mobile phones to provide access to GSM networks and applications.

Smart Card

The Smart Card is a secure portable token, used to provide secure, customized access to services, such as:

Public phone Key
Public printer Key
Entrance key for electronic gates
Electronic purse
Payment device for TV providers [satellite TV]

The main differences between the SIM and the Smart Card are:

The size of the card
Size and type of memory
Security Level [method and encryption engine]
Micro-controller type and power

SIM Evolution

SIM cards were first introduced in GSM as security tokens, but are now used as the central key to digital wireless systems security.

SIMs are now also used with some iDEN and CDMA networks, and are part of the 3G USIM applications in Wideband CDMA networks. By adding additional local authentication [PIN] the use of SIM cards has significantly reduced wireless fraud and unauthorized access to the network and as a barrier to subscription cloning.

GSM has been the driving force for the introduction of the Smart Cards.

The SIM was further developed to become proactive, able to trigger events that are then executed by the mobile equipment. This set of commands and procedures formed the basis for a new standard - the “SIM Application Toolkit” (SAT) (the GSM 11.14 standard approved by ETSI).

Today, SIM cards act as a platform for value added services, exploiting
the microcomputer in the SIM to provide:

Authentication algorithms and secret keys
Storage of the service profile and configuration data - preferred and forbidden roaming networks, SMS center address, available telephony services, voice mail number, service dialing number…etc
Storage of subscriber oriented data - such as speed dial number, short messages (SMS) and other calling features.
Storage of multimedia - video, photos, mp3 audio.

SIM and 3G

With the standardization of the SIM car, it was adopted by 3rd generation 3G wireless communications, as the Universal Subscriber Identity Module, or USIM. The terms SIM and USIM have become interchangeable.

The SIM as an independent entity inside the mobile phone provides a number of advantages, from CDMA phones using a fully integrated alternative:

Logistics

OTA - an efficient means of pushing new service files to end-users. This is known as Over-The-Air [OTA] activation. New services such as financial services and travel services help to reduce customer churn.

User Data - SIM cards separate subscription information and user data [contacts, media files] from the device, making it easy for customers to upgrade phones, without losing data or requiring a transfer of data. This reduces the customer support costs, operation costs and idle service time.

Network Agnostic - The separation of subscription information from the terminal devices renders the device network agnostic. This supports a global market and distribution network of phones, increasing competition and thereby helping to lower service costs to customers.

Accounting - by storing different subscriptions in one smart card, calls can be separately accounted between business and personal use.

Portability of information and Application

PCto Phone Data Transfer - SIM cards allow the transport of user data and specific applications from phone to phone and from home network to visited network.

Phone to Phone Transfer - moving the SIM card to a new phone transfers all speed-dial numbers without reprogramming them in the new phone.

Preferences Transfer - User services, data, and preferences are portable from phone to phone and network to network. This includes specific data such as speed dials and short messages, as well as applications and related data [digital signatures for securing transactions, phone settings].

Security

Theft - Prevent unwanted use of SIM cards in cases of theft or loss by activating the SIM card PIN code. The SIM will lock itself automatically after three wrong PIN insertions and can be unlocked only by the wireless service provider.

Transactions - Mobile devices provide authentication and digital signatures without the user’s consent. This is inadequate proof of customer agreement to the transaction; transactions can be easily denied, creating expensive consequences to merchants. Using a SIM card provides an appropriate level of security for transactions. Governments and financial institutions recognize smart cards as the most efficient way to transact over wireless phones.

Roaming

Inter-Network - roam between GSM to TDMA to CDMA networks, etc., ensuring maximum flexibility and “follow-me” features [voice-mail service, personal assistant service].

International - international roaming using the same billing account.

Next: Mobile Device Operating System