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Apple's iPhone 5 Lightning connector cable features 'mystery chip'

The Lightning connector for Apple's iPhone 5 has frustrated quite a few people with accessories that no longer work without a pricey adapter, but the new Lightning cable looks like it has something that they may come to appreciate - security.

True, it's pretty rudimentary security, as the teardown artists at ChipWorks found out when they took apart the iPhone 5's Lightning cable this week. In fact, if the site is right about the security features present on the cable, they don't even measure up to the security on modern printer cartridges, ChipWorks said.

But Lightning is also the "first secure cable we have seen," the site noted, adding that "with future generations of Apple and non-Apple products, we may begin to see even stronger security and control if the market forces merit it."

The cable houses four embedded chips, plus some passive devices, the key parts being a Texas Instruments integrated circuit with die markings labelling it "BQ2025" and NXP's NX20P3 IC, ChipWorks said. The TI chip isn't listed by the company in its product database but appears to share characteristics with four that are listed and which all "have some basic security features such as CRC generation," prompting the site to theorise that the BQ2025 has those features as well.

ChipWorks figured that the part in question is a serial communications chip that has battery gauge functionality, sporting "about 5K gates of logic," as well as "EPROM with likely 64 or 128 bits of storage ... some large driver transistors, quite a bit of analog circuitry, and a fair amount of capacitance."

Along with NXP's chip in the Lightning cable, the presence of the TI part goes a long way towards explaining how Apple is able to accomplish the same amount of sending and receiving of signals with just nine direct connections on its new nine-pin connector as the old 30-pin connector was capable of handling, according to the teardown site.

The TI chip may also have smart battery applications and "allow 'handshake' access to only certain functions necessary for the functioning of a peripheral ... without allowing access to the full functionality of the phone," ChipWorks said.

As Wired noted, that could mean the "mystery chip" might be able to "determine the needs of a particular piece of hardware plugged into an iPhone or iPod Touch and enable only the specific features necessary for the given task ... [f]or example, a speaker dock might get access only to digital audio and music player controls, with all other features being blocked or disabled."

ChipWorks also guessed that Apple may be playing another game by placing "modest" security in its new cable—namely "securing their revenue stream for cables or ensuring reliable and high quality (licensed) peripherals."

The site said it will be conducting a more comprehensive analysis of the Lightning cable in the future.