Can't decrypt iso with keydb

[dirtdigger]

Hello,

I have a disc that I've had trouble decrypting directly due to scratches (or so I think, there may be another issue there but that's another thread entirely). I was able to rip it to an ISO successfully using ddrescue, but now I cannot open that ISO in MakeMKV. Every time I try I get the error "The volume key is unknown for this disc - video can't be decrypted"

It seems that this is an AACS issue since I just ripped the disc without decrypting. I'm trying to get KEYDB.cfg working. I have that in my MakeMKV folder ~/.MakeMKV/KEYDB.cfg, and it appears that there are three different versions of my disc in the database. If I mount the ISO and find a sha1sum of AACS/Unit_Key_RO.inf, I get one that matches a line in my KEYDB.cfg.

Somehow I don't think MakeMKV is finding my KEYDB.cfg file. I tried playing around with the case (KeyDB.cfg, keydb.cfg, KEYDB.CFG) to no avail. Each time I change the filename I restarted MakeMKV in the hope that it would re-look for the file. I've also verified that the MakeMKV data directory is indeed pointing to the folder that contains the database in preferences.

Any suggestions? Thank you!

[beandog]

MakeMKV doesn't use libaacs to decrypt Blu-rays.

If the disc is that badly damaged, it might be a good idea to just replace it.

[megaminxwin]

Hi,

I've been having the same issue with a disc of my own, as it happens; however I can't replace it, as it's from a limited edition (and now out of print) boxset and there's no way to replace the disc without buying a new boxset for $200. What's particularly annoying is that the disc *looks* pristine, however it likes to throw up a bunch of bad sectors.

I have the key I need for the ISO, and I did manage to successfully create an ISO with ddrescue after a looong time; I even managed to recover the single troubled file from the disc (a 19 GB .m2ts file, woo). I know that MakeMKV supports creating files from a disc image, so why isn't it able to recognise that it already knows what keys it needs? What does MakeMKV look for when trying to find the keys to decrypt the files, and is there a way to force it to use a particular key for a particular disc image?

Thanks!

[pucgenie]

Hi, even libaacs can't decrypt 1:1 disc image files if it didn't have access to the original disc before*.
If MakeMKV handles that similarly, insert the original disc and hope that at least the menu works. Then try again with the ddrescue'd image.
I'm afraid you already tried this way (since more than a year passed already) and it doesn't work anyway...
* libaacs creates some files in ~/.cache/aacs - for comparison, KEYDB is placed in ~/.config/aacs

[Ezatoka]

Depending on where MakeMKV has troubles, you can just start an Encrypted Backup and as soon as the discatt.dat file was created (which should be at the very beginning), you can stop MakeMKV and copy that file into your ddrescue structure and it should open the files (I think).

Does anyone know if it would be problematic to share such discatt.dat files? I don't think I've ever seen a website collecting them, so if anyone is good in building such sites... maybe?

[Coopervid]

Not sure about the Linux process. Under Windows there is dvdisaster. For that it is important that no software in between is modyfying anything. No AnyDVD and no Makemkv being active. That program does then a 1:1 raw copy of the disc. Load the resulting ISO. Have Makemkv or AnyDVD work on the ISO loaded later. The programs will then use bus decrytion and AACS decryption on these loaded ISOs. It will not work if any of the programs had been active during the ripping process to get the data from these hard to read discs. Just my 2 cents. Assumption is that ddrescue works similar to dvdisaster.

[mambojambo]

I'm having the exact same issue here with the Lion King 4K. Normal ripping with MakeMKV looks like it's working, but is always failing at some point. So I took the time and created an iso with ddrescue after many attempts, but now decrypting this encrypted backup is failing for some reason. This process has worked fine with other non-4K blu-rays. I can fine the sha1 of AACS/Unit_Key_RO.inf in the keydb.cfg as well, so unfortunately I have to assume that the ISO is actually corrupt :/ Let's see if this happens again with another disk.

[SamSpeexy]

Just because ddrescue reports no errors doesn't mean it's correct. I recommend going to https://www.xreveal.com/ and download the free Content Hash Verifier 1.3 program for Linux. It will read the ripped ISO and see if the M2TS files have any errors.

[SamuriHL]

I'm not sure why no one is talking about bus encryption, but that is what you are running into. Blu-ray may or may not be bus encrypted which is why reading directly with ddrescue might work. But ALL UHD is bus encrypted. If you don't enable libredrive BEFORE creating the ISO, it will be useless. This is because the data is bus encrypted. Now if you have the read data key it could be decrypted but retrieving that is per disc and I don't know if a way to do that for aacs 2.x encrypted discs easily.

Tldr your ISO is useless. Enable libredrive first next time.

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