Empty trash on encrypted dmg volume

[Richard1028]

An attorney friend asked me something I couldn't answer and be sure 100% (He works with sensitive docs).

Using disk utility, he created an encrypted dmg volume where he keeps most of his critical documents. When he drags one of those docs from the encrypted volume to the mac's trash bin... does the trash still need to be emptied securely? This is what he's been doing but it takes so freaking long.

I say no because the file sitting in the trash can is really just a pointer to the already encrypted dmg volume where it came from. There's no reason for OSX to wipe drive space that's already secure.

Is this correct?

 

[angelwatt]

Yup, you're right. Each volume, including disk images, have their own .Trashes folder on them where the trashed folder is located. The Trash on the machine only sees a link to that file. So, when you empty the trash on your Mac it will simply relinquish the space on that volume and remove the point in the trash can. No need for a secure delete. I say all this with 99.5% confidence.