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My understanding of the Linux encryption protocol is that the keys are "distributed" over the entire disk, so even a tiny amount of damage can cause a significant amount of casualty. In particular, damage to the "master key" (not the password) basically renders the device non-functional unless you have a backup. I am talking here about hard disk encryption (at boot), not home directory encryption.

After mounting my device, the error I receive is familiar:

Command failed with code 1: No key available with this passphrase.

Assuming that I am using the same password, what else could cause this error? My disk image appears to contain a valid version of the header.

> cryptsetup -v luksDump /dev/sdb5
LUKS header information for /dev/sdb5

Version:        1
Cipher name:    aes
Cipher mode:    xts-plain64
Hash spec:      sha1
Payload offset: 4096
MK bits:        512
MK digest:      23 97 8b 80 e5 92 5a 2f dd c8 cf d9 c0 d1 e7 42 7c bc 3e 4f 
MK salt:        05 a5 10 62 46 45 36 8a 89 13 f1 94 0f 4b 9a 39 
                16 ca e0 f9 47 45 fd 0c 1b e0 bd e9 40 c4 91 d3 
MK iterations:  40500
UUID:           ef71756f-2724-4f44-90ed-29ddb760e73c

Key Slot 0: ENABLED
    Iterations:             161615
    Salt:                   f9 ad 13 c6 26 7f 59 c2 72 81 99 4f 67 b9 19 9e 
                            17 bc 17 75 96 d4 7d dd 74 4a d0 87 c7 b8 8d 95 
    Key material offset:    8
    AF stripes:             4000
Key Slot 1: DISABLED
Key Slot 2: DISABLED
Key Slot 3: DISABLED
Key Slot 4: DISABLED
Key Slot 5: DISABLED
Key Slot 6: DISABLED
Key Slot 7: DISABLED
Command successful.

I have actually been at this for a while and have a number of theories about what could've happened. Please help me knock these down to the most likely solution.

1) The damage to the hard disk caused the encryption keys to change.

2) I encrypted the disk on Ubuntu 14.04, and am trying to load it on Ubuntu 16.04. Because my password uses special characters, some input protocol is fudging this. In a number of projects I've done, strings containing "!" tend to confuse the command line. So I'm wondering if that could be happening here.

3) I encrypted the hard disk on one device, but am trying to load it on another device. See special characters comment in #2

4) I'm inputting the incorrect password

5) An attacker invaded my machine and re-encrypted it with an alternative password.

6) ... Other? Maybe it's starting at the wrong bit when reading the key?

Obviously #4 is the most likely solution to an outsider, but let's assume my password is correct. Then, theory #5 basically means I'm screwed, and is also unlikely, so let's ignore it for now. Are Theories #1-3 valid? What could Theory #6,7,8 be?

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  • Does the SMART data for the HDD indicate any recent R/W failures? Nov 21, 2016 at 20:31
  • The original disk was beeping / clicking and wasn't recognized by USB. Didn't make sense for me to try a platter switch without a clean room so I sent it to a few "harddrive recovery experts" but they had never even heard of LUKS encyrption. They seemed to think that the header wouldn't even be readable, but then how come my header is valid? Nov 22, 2016 at 7:52
  • One of the hard drive experts was able to image the disk though and the partition layout is mine I think. One more thing I found online. 7. The one and only keyslots is damaged. I'll edit or add a comment when I investigate this. Nov 22, 2016 at 7:53
  • I have started a thread on ubuntuforums.com. A few comments have been made by others; perhaps there is someinformation there for someone who is undergoing the same problem. ubuntuforums.org/showthread.php?t=2346612 Jan 3, 2017 at 23:12

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