Turbo SIM

The Turbo SIM (also known as TurboSIM) is considered the forerunner of a large family of "Dual SIM" devices (HyperCard, HyperSIM, China3GPP, StealthSim, MagicSIMetc.) that piggyback on a telephone SIM card to alter its normal operation. It was introduced in December 1, 2004 by BLADOX, located in Prague, Czech Republic. It is a very thin device with a 9mm by 9mm EEPROM mounted in the top right corner. It has the makers name BLADOX in gold letters on its black PCB. It is pressed on top of a normal SIM card (with some plastic cut off) in such a way that it is still small enough to be inserted into the SIM card slot of any GSM phone. Without the product, the SIM card is still usable as before.

The Turbo SIM is claimed to work with any GSM mobile phone produced since 1998, and can be used to add new functionality such as larger SMS archives to some phones. [http://www.bladox.com/doc/turbo_sim_pr_en.pdf] In general, dual SIM technologies have been found to fail to work with some phones.

This device, and those like it, use a small microcontroller (the original Turbo SIM used an Atmel ATmega128) to intercept traffic between the cell phone and the original SIM card, and modify this traffic based on programming stored in the microcontroller.

More specifically, the Turbo SIM can be used to spoof the IMSI number and authentication key (Ki) supplied by the SIM card to the network, allowing network-locked phones (such as the Apple iPhone [ [http://arstechnica.com/journals/apple.ars/2007/08/14/turbo-sim-add-on-allows-full-iphone-unlocking Turbo SIM add-on allows full iPhone unlocking ] ] [ [http://asia.cnet.com/reviews/mobilephones/0,39050603,62030927,00.htm iPhone hacked by Aussie using "Turbo SIM" - CNET Asia ] ] , and more recently NTT DoCoMo and SoftBank phones) to be used on mobile networks for which they were not originally designed or permitted.

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