• This way the phone could be unlocked and used with the visual pattern. (Or some other mechanism, e.g. fingerprint, face scan, etc.)
  • The SIM card PIN wouldn't have to be repeatedly input after every restart.
  • In case the SIM is removed and put in another phone, it would require PIN to access.
  • The PIN would likely be encrypted while stored on the phone so it cannot be easily (or perhaps in any way) recovered without getting through Android's built in unlocking mechanism.
  • Maybe the SIM would only be unlocked after the first time the Android phone itself is unlocked after reboot. And that's okay, maybe even desirable.
  • I don't mean the option to disable the SIM PIN completely, as that makes it very easy to put the card in another phone to have unfettered access.
  • 1
    i haven't heard of anything like that, i suppose it's possible but it'd require system level access to change the application responsible for handling PIN entries... It'd be a nice new security feature, maybe suggest it to Google or Copyright the idea and call it Wizek SIM Security or something :) Nov 24, 2018 at 22:12
  • If the phone would save the PIN it could be extracted using a specially crafted SIM card that simply receives the PIN and saves it internally. This ist not as simple as just using a SIM with disabled PIN, however if one Android manufacturer would implements the save SIM feature I am sure that there would be such PIN stealing SIM cards available to buy fastly.
    – Robert
    Jan 6, 2019 at 14:54
  • @Robert, Yes, that's why I wrote my 5th point: "Maybe the SIM would only be unlocked after the first time the Android phone itself is unlocked after reboot. And that's okay, maybe even desirable." This way, the SIM is only unlocked if the phone is used by someone who already knows how to unlock the phone itself, and the PIN cannot be stolen via a man-in-the-middle attack.
    – Wizek
    Jan 7, 2019 at 15:40
  • @Robert In fact, there could be a continuum between security and convenience for people to choose from: (1) no pin, no phone lock, (2) no pin, yes phone lock, (3) auto unlock pin on startup (allows MITM sim attack, might not matter for most people, as this would likely be a step up for them from no-pin anyway), (4) auto unlock pin on first phone unlock (safe against MITM, doesn't allow receiving calls before first unlock, which doesn't sound much of an issue for me), (5) require pin, require phone unlock too.
    – Wizek
    Jan 7, 2019 at 15:50
  • Currently only 1, 2 and 5 are possible. I think 3 and 4 would be a sweet spot for security and convenience. Most people would likely happily step up from 2 to 3 to get more safety without losing much any convenience. And some might step down from 5 to 4 as they don't lose much any security while gaining quite a bit of convenience.
    – Wizek
    Jan 7, 2019 at 15:53


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