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Making a protected backup?
Posted: Fri Feb 19, 2021 6:14 pm
by archiveEverything
From following this thread, it sounds like MakeMKV should be able to read a protected ISO, so long as bus encryption has been removed:
https://www.makemkv.com/forum/viewtopic ... 4&start=60
Is that only for UHD?
I tried opening a protected Blu-Ray ISO I previously made, and MakeMKV 1.15.4 stalls on parsing ContentHash001.tbl for about a minute and half, after which I get "The volume key is unknown for this disc - video can't be decrypted".
Strangely, if I put in the original disc, MakeMKV only spends about 5 seconds on ContentHash001.tbl and
does seem to have the key for this disc.
Stranger still, if I
then open the ISO, MakeMKV still stalls on ContentHash001.tbl, but eventually is able to proceed and decrypt the disc. But only until I exit MakeMKV. The next time I run MakeMKV, it says it doesn't know the key for the ISO.
Did I do something wrong?
Re: Making a protected backup?
Posted: Wed Feb 24, 2021 7:57 pm
by Fisk123
Maybe I have the same Problem. - I try to open a Disc, I have made a backup from to my SSD-Drive.
Everytime I try to open the BDMV-File or the MKB_RO.inf I got the message "video can't be decrypted Failed to open disc".
Re: Making a protected backup?
Posted: Thu Feb 25, 2021 2:40 pm
by archiveEverything
How did you create your backup? It sounds like you did a disc backup within MakeMKV?
I created a protected ISO outside of MakeMKV (see the linked thread in the original post), since MakeMKV doesn't offer that functionality.
If we're both having this issue, using very different backup mechanisms, maybe there's a bug in how MakeMKV reads protected backups?
Re: Making a protected backup?
Posted: Thu Feb 25, 2021 8:36 pm
by Fisk123
Yes, I created the backup with MakeMKV.
Re: Making a protected backup?
Posted: Thu Feb 25, 2021 9:30 pm
by dcoke22
What happens if you make a decrypted backup with MakeMKV?
Re: Making a protected backup?
Posted: Fri Feb 26, 2021 7:32 am
by kelivufi
archiveEverything wrote: ↑Fri Feb 19, 2021 6:14 pm
From following this thread, it sounds like MakeMKV should be able to read a protected ISO, so long as bus encryption has been removed:
https://www.makemkv.com/forum/viewtopic ... 4&start=60/
Is that only for UHD?
I tried opening a protected Blu-Ray ISO I previously made, and MakeMKV 1.15.4 stalls on parsing ContentHash001.tbl for about a minute and half, after which I get "The volume key is unknown for this disc - video can't be decrypted".
Strangely, if I put in the original disc, MakeMKV only spends about 5 seconds on ContentHash001.tbl and
does seem to have the key for this disc.
Stranger still, if I
then open the ISO, MakeMKV still stalls on ContentHash001.tbl, but eventually is able to proceed and decrypt the disc. But only until I exit MakeMKV. The next time I run MakeMKV, it says it doesn't know the key for the ISO.
Did I do something wrong?
try this with a different disk image
Re: Making a protected backup?
Posted: Sat Feb 27, 2021 6:06 pm
by archiveEverything
I've tried it with dozens of protected ISO disc images.
MakeMKV claims it doesn't have the necessary key for the ISO, but if I insert the physical disc, it does until I quit. Without an internet connection.
This is still happening in 1.16.0.
Re: Making a protected backup?
Posted: Sat Feb 27, 2021 11:18 pm
by MartyMcNuts
archiveEverything wrote: ↑Thu Feb 25, 2021 2:40 pm
How did you create your backup? It sounds like you did a disc backup within MakeMKV?
I created a protected ISO outside of MakeMKV (see the linked thread in the original post), since MakeMKV doesn't offer that functionality.
If we're both having this issue, using very different backup mechanisms, maybe there's a bug in how MakeMKV reads protected backups?
ISO's are not exactly the same as an original disc, even when still encrypted.
Your ISO's are no good for this procedure as they do not contain the VolumeID from the disc. When MakeMKV is used to create an encrypted folder, it creates a discatt.dat file which contains the VolumeID from the disc. Protected ISO's created elsewhere generally do not contain this information, therefore, MakeMKV cannot complete the aacs process and obtain the volume key.
Your best bet is to start over and use MakeMKV to decrypt the original disc.
Re: Making a protected backup?
Posted: Wed Mar 03, 2021 6:56 pm
by archiveEverything
Right, but following the originally linked thread further:
https://www.makemkv.com/forum/viewtopic ... =90#p82173
It sounds like anyone having submitted the AACS information from the original disc key would provide the key necessary to decrypt the protected ISO. Does it not?
Re: Making a protected backup?
Posted: Wed Mar 03, 2021 10:12 pm
by MartyMcNuts
I think that is correct for UHD as MakeMKV has a list of volume keys but not for standard blu-ray.
MakeMKV follows the normal aacs decryption process for standard blu-ray which calculates the volume key. This cannot be done without the VolumeID from the disc (or discatt.dat file).