Apple patent application reveals method to block chip overclocking

“On January 29, 2015, the U.S. Patent & Trademark Office published a patent application from Apple that reveals a solution to counter a common hacking method involving clock overdriving,” Jack Purcher reports for Patently Apple.

“A common method used to attack systems is to overdrive the clock input into one of the processing chips in the system,” Purcher reports. “Apple notes that in order to help defend a system from being affected by clock attacks, some SoCs may include a clock monitoring circuit. A clock monitoring circuit, or clock monitor, is a means for determining if a clock signal is running at a frequency above or below a designated frequency.”

Read more in the full article here.

MacDailyNews Take: Clockblockers!

[Thanks to MacDailyNews Reader “Arline M.” for the heads up.]


  1. I hereby declare this action to be called… “clock-blocking” 🙂

    It sounds like they’re trying to prevent some kind of hack or attack, though it could of course also prevent advanced users from running their systems at a higher speed.

    1. Yes. I’d say Apple’s patent probably has a lot more to do with protecting hardware than it does security. Over locking raises the temperature of the device. When it overheats, it’s much more likely to stop operating altogether than it would be to go into some simple minded state where someone could access your data. And what hacker is going to go through all this trouble to try to maybe gain access?

    2. The iCore processors are self regulating, once the heat reaches a certain point the clock throttles back, so it seems that Apple will try to implement the same thing in the processors it designs (which may be an indication that they’re working on turbo boosting).

  2. I thought many of these processors will automatically run at faster than the rated speed (turboboost?). Maybe they want to stop someone from permanently turbo boosting a processor? Has this been done? Seems like it could be done in software.

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