Decrypting LUKS drive

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xApxQMSVn8PsYe
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Decrypting LUKS drive

Post by xApxQMSVn8PsYe » Fri Jan 04, 2019 6:24 pm

I have an encrypted luks drive on my system with nothing but pictures on it, it there a way I can decrypt it from the "Disks" application?

Mute Ant
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Re: Decrypting LUKS drive

Post by Mute Ant » Wed Jan 09, 2019 5:30 pm

'is there a way I can decrypt it from the "Disks" application' Yes.

[1] I Don't Know The Passphrase
You will always get prompted for the Passphrase to unlock the files. There's no back-door... no Passphrase, no files.

The Application Disks will recognise a volume as a LUKS device and can duplicate it without a passphrase to make a Partition Image. That's a file in a different file-system that's the same size as the source-volume. The Partition Image includes the LUKS header and the encrypted data, so it can be unlocked and mounted the same as the original bare-metal LUKS.

Making a copy of an encrypted volume is a 'not recommended' security weakness. Copying the LUKS header is generally bad news if a Black Hat operator gets at it. They don't need the whole image, just the first few MB is enough to practice a brute-force attack to find a Passphrase that will also unlock the original volume. It can be really useful to be able to do this though e.g. When you absolutely have to backup an encrypted machine and the owner of the data is...
[drunk | closeted | asleep | confused | absent] (...although I love her really :)

[2] I Do Know The Passphrase
In Disks near the display of the LUKS volume there's a 'locked' padlock icon. Clicking that prompts you for unlocking. Then Disks can make a Partition Image of the decrypted version.

[3] Why Use Disks?
For a simple Ext4-in-LUKS volume, using the Application Disks is not necessary. You click on the volume in the sidebar of your File Manager...
2.0 TB Encrypted
...it says on my machine. Clicking prompts for the Passphrase and mounts it for you.

[4] Ubuntu Made The LUKS Automatically
If your LUKS volume is a left-over from an Ubuntu install it won't be a simple 'click-me'. They are Ext4-in-LVM-in-LUKS and there's a two-stage unlocking process, like this... viewtopic.php?t=236864#p1261047
While you're waiting, read the free novel we sent you. It's a Spanish story about a guy named "manual".

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