Mac FileVault...how secure is it?

[JackBootThug]

I'm just curious. I read that iPhones (with a pass code of course) are even giving police departments in the US trouble. They can't get in.

What about an encrypted mac?

 

[asriznet]

I personally don't ever feel the need of encrypting my data.

I've seen cases where FileVault slows down the system really bad.

Especially if you're the kind that will utilize the your storage to more than 90%

Decrypting/encrypting will take a long time as well depends on how much data you have.

 

[EldonChew]

It uses XTS-AES 128 encryption

National Institute of Standards and Technology explicitly endorses it here

Pretty secure if you don't use simple passcode etc..

Try those generated with Keychain Access

 

[JackBootThug]

Eldon,

Thanks for the reply. But why is an iPhone so secure with only a 4 numeral pass code? Or when you say don't use "simple" pass code do you mean avoid using "1,2,3,4" and other stupid pass codes?

 

[EldonChew]

More to it other than not using simple pass codes

By setting up a device passcode, the user automatically enables Data Protection. iOS supports four-digit and arbitrary-length alphanumeric passcodes. In addition to unlocking the device, a passcode provides entropy for certain encryption keys. This means an attacker in possession of a device can’t get access to data in specific protection classes without the passcode.

The passcode is entangled with the device’s UID, so brute-force attempts must be performed on the device under attack. A large iteration count is used to make each attempt slower. The iteration count is calibrated so that one attempt takes approximately 80 milliseconds. This means it would take more than 51⁄2 years to try all combinations of a six-character alphanumeric passcode with lowercase letters and numbers.

Secure Enclave

Spoiler

The Secure Enclave is a coprocessor fabricated in the Apple A7 or later A-series processor. It utilizes its own secure boot and personalized software update separate from the application processor. It provides all cryptographic operations for Data Protection key management and maintains the integrity of Data Protection even if the kernel has 
 been compromised.

The Secure Enclave uses encrypted memory and includes a hardware random number generator. Its microkernel is based on the L4 family, with modifications by Apple. Communication between the Secure Enclave and the application processor is isolated 
 to an interrupt-driven mailbox and shared memory data buffers.

Each Secure Enclave is provisioned during fabrication with its own UID (Unique ID) 
 that is not accessible to other parts of the system and is not known to Apple. When 
 the device starts up, an ephemeral key is created, entangled with its UID, and used to encrypt the Secure Enclave’s portion of the device’s memory space.

Additionally, data that is saved to the file system by the Secure Enclave is encrypted with a key entangled with the UID and an anti-replay counter.


The Secure Enclave is responsible for processing fingerprint data from the Touch ID sensor, determining if there is a match against registered fingerprints, and then enabling access or purchases on behalf of the user. Communication between the processor and the Touch ID sensor takes place over a serial peripheral interface bus. The processor forwards the data to the Secure Enclave but cannot read it. It’s encrypted and authenticated with a session key that is negotiated using the device’s shared key that is provisioned for the Touch ID sensor and the Secure Enclave. The session key exchange uses AES key wrapping with both sides providing a random 
 key that establishes the session key and uses AES-CCM transport encryption.

Also, in iOS 8, Apple no longer holds on to the encryption key so they cannot unlock your phone even with a court order

You can read more here https://www.apple.com/privacy/docs/iOS_Security_Guide_Oct_2014.pdf

 

[neubie]

if not mistaken, if the passcode is entered incorrectly subsequently ten times, the phone contents can programmed to be wiped out.

 

[asriznet]

if not mistaken, if the passcode is entered incorrectly subsequently ten times, the phone contents can programmed to be wiped out.

Yes you can turn on that option but I rather not for me just in case.

If i forgot my own passcode, i would definitely want the freedom to attempt more than 10 attempts even if I'm going to fail in the end.

after all I can still wipe manually after that after giving up trying to bypass the passcode.