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I'm running Mavericks and have FileVault set for the whole disk. Is there any value then, in emptying the Trash securely? Given the whole disk is encrypted.

I'm not certain on how these two methods interact/ overlap.

Thanks.

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Secure Empty Trash and FileVault are two different methods for protecting data. FileVault encrypts everything on the hard drive. Only someone with an admin password can decrypt them. This includes anything in your Trash. So by default, the files you delete when FileVault is on are safe via encryption. Even if someone recovered them, they'd still need your password to decrypt.

Secure Empty Trash has nothing to do with encryption. The default Empty Trash just deletes pointers to old files and marks the space they were using on the hard drive as free to use in the future. However, the files are still there if someone ran a data recovery tool or until the OS decides to put a new file over them. Secure Empty Trash prevents recovering deleted files by writing data (zeros) over the space the files you're deleting were using. Meaning the files are completely destroyed.

Here's how it breaks down:

FileVault On | Empty Trash (non-secure) | Someone can still recover those files, but they will recover files that are encrypted per FileVault

FileVault On | Secure Empty Trash | No one can recover the files, so it doesn't matter whether they were encrypted or not to begin with.

Do you need to use Secure Empty Trash with FileVault on? I think it's overkill unless you're afraid that someone will recover files and have your password ready for decryption.

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    This is a good answer. The only thing I would emphasize is that the two are completely separate. Once the drive is accessed (via your admin password), trash behaves exactly the same as if the drive were not encrypted. A secure empty of the trash does a 7X write over the deleted files. So, in this sense, it's not overkill. Good answer though. – njboot May 16 '14 at 19:12
  • Agreed. Overkill is subjective. If there's fear that someone will obtain the admin password, then it's not overkill. That's a good clarification though. – sgelliott May 16 '14 at 21:18
  • I strongly disagree with this answer and here's why: When traveling abroad, for example to the U.K., you can be LEGALLY COMPELLED to supply your password to the authorities. That's right, under Second 7 of U.K., if you do not comply when asked for your encryption password you are a criminal. Furthermore, this answer does not educate users for SSD drives — SECURE ERASE IS A MYTH. The NSA and other gov't agencies have technology to read prior data that was overwritten by a secure erase —making secure erase on SSD drives useless. – Jason FB May 21 '17 at 12:07
  • @JasonFB You're adding context (SSD specific) and additional information regarding legal demands in a specific country a year later. Valuable additions for certain, but I don't see a negation of the information on the whole. Legal requirements to provide a password are tenuous at best. Can they prove you remember your password? A whole other discussion really. To add some additional detail to the matter of SSD specific wipes (which I was not addressing originally)... usenix.org/legacy/events/fast11/tech/full_papers/Wei.pdf – sgelliott Jun 24 '17 at 8:42

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