I am not sure what I am missing, but decryption the sdcard should be as easy as opening it if it it that few possible combinations. So what's the point of it?

To clarify I mean booting into recovery mode, ADBing, and trying to decrypt the partition directly, without artificial timeouts that OSes do.

  • I think it definitely makes a better question at Information Security SE – SarpSTA Feb 26 '18 at 19:17
  • @SarpSTA I gave the security point of view in the question, I am expecting to get something different here than security. (unless that's really there is) – LyingOnTheSky Feb 26 '18 at 19:28
  • Even if there is such a point, I still think ISSE would be better at answering it. Nothing wrong with asking the question here of course. – SarpSTA Feb 26 '18 at 19:32

Countering your supplemental conditions...

To clarify I mean booting into recovery mode, ADBing, and trying to decrypt the partition directly, without artificial timeouts that OSes do.

  • Stock recovery doesn't have regular ADB capability (only ADB sideload, and that only flashes signed firmware).
  • Even with USB Debugging enabled, you can't authorize a random PC to debug over ADB, since the authorization dialog is behind the lockscreen.
  • Can't read/pull anything from /data even if you have ADB authorization, unless the device is rooted.
  • Can't flash a custom recovery without unlocking the bootloader, which nowadays requires flipping a switch in Settings - Developer options, again behind the lockscreen. Unlocking also fully wipes all data including the internal storage.
  • If the bootloader is already unlocked then theoretically none of the security measures would ever matter - but such is a very rare case for regular users, and anyone who do it would (or should) know the risk well already.
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  • my question doesn't still stands? if someone has access to the storage directly, then it can decrypt the data easily, if that someone not, then it doesn't matter if the underlying storage is encrypted or not. Is that correct? – LyingOnTheSky Mar 2 '18 at 13:20
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    Having "access to the storage directly" is not trivial - with the above constraints, the attacker will have to physically possess the device and obtain the data from a lower level (e.g. blowing the flash chip off and reading directly off it). If your data is worth so much trouble and you're vulnerable to losing the device physically then naturally data safety no longer matters to you - you wouldn't be using a consumer-grade device anyway. – Andy Yan Mar 2 '18 at 14:34
  • So you didn't deny that the encryption is useless with the above constraints, and direct storage access. I asked the question because I had corruption in my storage that made it undecryptable with the regular OS/Recovery-mode, and I had to go through so much trouble to decrypt it. (and I preferred it being unencrypted even more if it's useless) – LyingOnTheSky Mar 2 '18 at 15:11

You are likely looking at an incorrect assumption that you can exhaust all possible combinations uninterrupted, in a short period of time.

Which is incorrect because after 5 failed attempts, you are barred from entering PIN / password and a pause of 30 seconds is introduced before you try again or you would need to reset your phone to be able to use a new PIN. I am not sure how one plus implements this and may vary a little bit that's the standard expected behaviour called rate limiting. See my answers here and here

Note This answer was before the question was edited and Andy Yan's answer deals with çhanges made to question

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  • you can bypass that by adbing the phone, copy the partition to your PC and do whatever you want with it. – LyingOnTheSky Feb 27 '18 at 5:12
  • I said cracked under a second with any modern processor, I didn't thought I had to describe the entire process of cracking it. – LyingOnTheSky Feb 27 '18 at 5:36

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