Narrow Margin MKV fails, Leawo Succeeds

[BrianDW]

Just got Narrow Margin 4K. A Kino Lorber release from several months ago.
Downloaded latest keydb from FindVUK Online Database and tried to convert with MAKEMKV.
"The volume key is unknown for this disc - video can't be decrypted" error on three attempts.

Checked the forum and noted the dump file had been submitted.
Checked various Torrent and Newshosting sites and noted that 4K remuxes were available. (I didn't attempt to verify if these actually worked.)

Then attempted decryption with Leawo Professional Media UHD Ripper.
Success on first attempt. Same computer, same drive, same disc. Disc was not removed from drive between (failed) MAKEMKV attempts and successful LEAWO attempt.

Then I (again) downloaded the latest keydb and tried with MAKEMKV again and it failed again.
How is a disc released months ago that has apparently been decrypted (and uploaded to torrent sites) failing now? Why is the oft derided LEAWO working when the lauded MAKEMKV does not?

[MrPenguin]

Then I (again) downloaded the latest keydb and tried with MAKEMKV again and it failed again.
How is a disc released months ago that has apparently been decrypted (and uploaded to torrent sites) failing now? Why is the oft derided LEAWO working when the lauded MAKEMKV does not?

It's difficult to be sure without knowing more about your disk.

My guess would be that KEYDB contains your disk's Unit Key, but not its Volume Unique Key (VUK). So providing LEAWO can also disable bus encryption, knowing the Unit Key would allow it to decrypt your disk. However, if its "hashed keys" database doesn't work, MakeMKV requires that KEYDB contains your disk's VUK.

Someone would need to examine your disk's TGZ dump file to give you a more definitive answer.

[BrianDW]

Does very single disc have a unique VUK?

[MrPenguin]

Does very single disc have a unique VUK?

Yes, in theory. Disk manufacturers have been known to make silly mistakes though, including failing to encrypt some disks in the first place!

[BrianDW]

So, wouldn't that mean that for every single one of the UHD blu-rays decrypted with MAKE MKV a unique dump file would have to be submitted?
I have decrypted hundreds of UHD titles successfully on the first try without an error requiring the dump file to be submitted.
How was the volume key unique to my disc known without me submitting?


Obviously, some piece of knowledge has escaped me.

[MrPenguin]

How was the volume key unique to my disc known without me submitting?

Oh, I see the confusion. Disk manufacturers create a small number of "master disks" for each release, and every disk sold is a copy of one of those master disks. Every master disk (should) have a globally unique VUK.

I have decrypted hundreds of UHD titles successfully on the first try without an error requiring the dump file to be submitted.

Which means that someone had already submitted a dump for a disk created from the same master disk as yours.

[BrianDW]

Got it. Thank you.