enter passcode after restart...

Discussion in 'iPhone' started by McDLT, Oct 21, 2014.

  1. McDLT macrumors regular

    Feb 11, 2006
    is this for security or something? i thought the whole id of touch id was that it's more secure than passcodes. for that matter, i don't understand why you are allowed to enter a code or a fingerprint all the time. seems like it should just be the print. what am i missing here?
  2. kilcher macrumors 65816


    Jul 3, 2011
    Print is more convenient. There's probably a better reason but that's the way I see it.
  3. eclipse01 macrumors 68020


    May 16, 2011
    Eau Claire, WI
    Could be something as simple as there way of showing you that the phone actually restarted.
  4. JayLenochiniMac macrumors G5

    Nov 7, 2007
    New Sanfrakota
  5. rritterson macrumors 6502

    Jul 10, 2008
    DC USA
    IIRC, userland is encrypted with the passcode. I wonder if inputting the passcode after restart is required to decrypt things.
  6. DarkJaye macrumors member

    May 11, 2009
    Entering a passcode basically unwraps an encryption key that's used to secure files on your device. On pre-Touch ID devices, locking the device throws away the unwrapped key, requiring you to enter your passcode again to unlock the phone.

    On Touch ID devices, the unwrapped key is handed off to the Touch ID subsystem when the device is locked. So if you restart your phone, the Touch ID subsystem has no key to provide to unlock the phone. You need to enter the passcode at least once so it has the key to unlock the phone.

    The Touch ID subsystem also deletes the key after 5 unsuccessful fingerprint reads, or after 48 hours of the phone being locked. It also deletes the key if Lost Mode is activated via Find My iPhone.

    This is all for security, in case your phone is stolen and they try to use a copy of your print to unlock it, or to force your finger onto the sensor to unlock your phone against your will.

    Touch ID is not more secure than a complex alphanumeric passcode (although it is more secure than a 4 digit PIN), but serves as a relatively secure mechanism to prove that you're the person that knows the passcode. It's not a complete replacement, just a convenient alternative.
  7. EM2013 macrumors 65816


    Sep 2, 2013
    I don't mind that you have to enter your password after a restart but I hate that you have to re-enter your password for your Apple ID when you purchase an app or song.
  8. myscrnnm macrumors 65816


    Sep 16, 2014
    Seattle, WA
    Passcodes are potentially more secure. Touch ID is mainly for convenience. This is why the passcode has precedence over Touch ID after restarting the phone.
  9. miamialley macrumors 68030


    Jul 28, 2008
    Los Angeles, CA
    I wondered the same. I'm sure it's just for extra security, but it does seem unnecessary. I also get annoyed to have to manually enter my iTunes password after restarting.

Share This Page