Mac Inside & Out · macOS Under the Hood · Lesson 4 of 5

Apple Silicon and the Secure Enclave

Learn what Apple's own chips do and how Touch ID keeps your print safe.

One chip that does it all

Every computer has a processor, the part that does the thinking. For years, Macs used processors made by Intel. Starting in 2020, Apple began making its own.

Apple silicon is the name for Apple's own Mac chips. They're called M1, M2, M3 and later. Each one is a system on a chip, which means many parts are built into one piece:

• The main processor, which runs your apps.
• The graphics part, which draws everything on the screen.
• The memory, shared by all the parts so they can work together quickly.
• Special parts for tasks like video and security.

Keeping it all on one chip saves power. That's why many Apple silicon laptops stay cool and run a long time on battery.

To see which kind you have, open the Apple menu and choose About This Mac. An Apple silicon Mac lists its chip, like "Apple M2". An older Intel Mac shows a Processor line naming Intel.

What about apps written for Intel Macs? Rosetta 2 is a built-in translator. It quietly converts an Intel app so it runs on Apple silicon. The first time you open such an app, your Mac may offer to install Rosetta. Apple has said Rosetta will be phased out over the next few years, and recent versions of macOS warn you when an app depends on it. If you see that warning, check the maker's site for an Apple silicon version.

On Windows, most PCs use Intel or AMD processors, and some newer ones use Arm chips like iPhones do.

The Secure Enclave and Touch ID

Inside Apple silicon is a special locked room called the Secure Enclave. It's a separate security processor with its own memory and its own startup steps. The rest of the Mac can't reach inside it.

If you took the iPhone lessons on the Mobile side, you met the Secure Enclave there. The Mac's works the same way. Some older Intel Macs have one too, inside a chip called the T2.

The Secure Enclave guards your most private secrets. These include the keys that lock your disk and the data behind Touch ID.

Touch ID is the fingerprint button at the top right of many Mac keyboards. You can use it to unlock your Mac, approve purchases and fill in passwords.

Here's what happens to your fingerprint:

• Your Mac doesn't save a picture of it. It saves a math version that can't be turned back into a print.
• That data is locked by the Secure Enclave and stays on your Mac.
• It isn't sent to Apple and isn't saved in your iCloud backup.
• Apps never get your fingerprint. They only hear "yes, it matched" or "no".

Touch ID still needs your password sometimes, like after a restart. That keeps the password as the main key.

On Windows, Windows Hello does a similar job with a fingerprint reader or face camera. Like the PIN you learned about earlier, it stays on that one device.