SIM Application Toolkit

SIM Application Toolkit (commonly referred to as STK) is a standard of the GSM system which enables the SIM to initiate actions which can be used for various value added services. [http://www.cellular.co.za/sim_toolkit.htm SIM Toolkit ] ]

The SIM Application Toolkit consists of a set of commands programmed into the SIM card which define how the SIM should interact directly with the outside world and initiates commands independently of the handset and the network.http://www.gemplus.com/techno/stk/] This enables the SIM to build up an interactive exchange between a network application and the end user and access or control access to the network. The SIM also gives commands to the handset, such as display menu and ask for user input. [http://www.gsmmobile.co.nz/Sim_Toolkit.htm SIM Toolkit ] ] http://www.3gpp.org/ftp/tsg_t/WG3_USIM/TSGT3_10/docs/t3-99346.doc]

STK has been deployed by many mobile operators around the world for many applications, often where a menu-based approach is required, such as Mobile Banking and content browsing.Designed as a single application environment, STK can be started at the initial power up of the SIM card and is especially suited to low level applications with simple user interfaces.

In GSM 2G networks SIM Application Toolkit is defined in the GSM 11.14 standard in 1995.

Advantages

* Some manufacturers claim that STK enables higher levels of security through identity verification and encryption, which are necessary for secure electronic commerce. [http://bladox.com/devel-docs/gen_stk.html SIM Toolkit ] ]
* STK has been deployed on the largest number of mobile devices.

Limitations

* After a SIM has been delivered to the customer it can be difficult to change the STK applications and menus on the SIM. To do so either the SIM must be returned and exchanged for a new one which is costly and inconvenient or in some cases the applications can be updated over the air.

It is possible today to change STK Menu for S@T based applications quickly Over The Air via SMS bearer. For BIP compliant SIMs and when the handset is BIP compliant, it can be very fast(GPRS/3G speed).It might also be possible to change the menu of WIG based STK applications.

[http://www.gemplus.com/press/archives/2004/telecom/15-06-2004-ota_saudi.html] [ [http://www.smartcardalliance.org/industry_news/industry_news_item.cfm%3FitemID%3D357 Gemplus to Deliver SIM Card-Based Solution to Oi For First GSM Launch in Brazil - Smart Card Alliance ] ] This limitation hinders the number and frequency of STK application deployment. [http://www.mygemplus.com/pss/telecom/download/GemConnect_online_sdk.pdf]
* No multimedia support (only basic pictures)
* Poor independent development support

With the current OTA platforms it is possible to change the menu structure and the services available on the SIM without the users having to return the SIM or even take it to the operators business center.

TK in 3G

USIM Application Toolkit (USAT) is the equivalent of STK for 3G networks.

References