Inject discatt.dat into ISO

[Anuskuss]

I did a backup of my Blu-ray disc using dd but MakeMKV is not able to decrypt it. I did a MakeMKV (directory) backup which give me the same files (same checksums) as the ISO but includes an additional discatt.dat.
Is it possible to inject that file into the ISO (header)?

P.S. Right now MakeMKV doesn't have an easy way to even load ISO + disccatt. I have to mount the ISO, symlink the directories into a temporary directory and then also symlink the discatt.

[Billycar11]

Depends if you disabled buss encryption or not on the dd copy if not no it putting the .dat file won't work.

To disable buss encryption you open the disc in makemkv first then go to do your dd

[Anuskuss]

To disable buss encryption you open the disc in makemkv first then go to do your dd

I think that only works for DVDs? Because I did open it in MakeMKV and it gave me the same ISO.

[SamuriHL]

No it only works with libredrive compatible drives. Libredrive will disable bus encryption, allowing you to then create your ISO image. But you can't eject the disc once libredrive is enabled until after the ISO is created.

Sent from my SM-S928U1 using Tapatalk

[Billycar11]

yeah that too what drive you have?

[Anuskuss]

yeah that too what drive you have?

Just a random one off Amazon (aelrsoch).

No it only works with libredrive compatible drives.

I might invest into something like that. Sounds useful.

I have to return the disc today so I won't be able to do another backup. Anything else I can do? I have a dd ISO, encrypted MakeMKV directory and decrypted MakeMKV directory. Will probably delete everything and only keep the ISO and discatt.

[Billycar11]

yeah that too what drive you have?

Just a random one off Amazon (aelrsoch).

No it only works with libredrive compatible drives.

I might invest into something like that. Sounds useful.

I have to return the disc today so I won't be able to do another backup. Anything else I can do? I have a dd ISO, encrypted MakeMKV directory and decrypted MakeMKV directory. Will probably delete everything and only keep the ISO and discatt.

ah yeah that wont work then

if your in the usa i have pioneers with old fw if you want one they are the best libredrive drive's

[Anuskuss]

if your in the usa i have pioneers with old fw if you want one they are the best libredrive drive's

Thanks for the offer but unfortunately I live in Germany and the shipping would probably be more that the drive itself.

ah yeah that wont work then

I mean I did get the MKVs in the end so that's really all that matters but does that mean my ISO is not "perfect"? I thought that maybe the drive would not let you read some sectors (my DVD drive does the same if I don't open MakeMKV prior) but that the dump would be complete otherwise. And that if I inject the missing bits from the discatt.dat I'd be set. Software like CyberLink's PowerDVD doesn't play the ISO either so that's why I'm keeping a decrypted MakeMKV backup just in case. I could probably replace the ISO filesystem in-place (leaving anything else intact like the header, file position, timestamps etc) but I felt like that would be even less of a "perfect" backup. Anything else you'd recommend other than get another drive? I really only do DVD backups anyway so it's not really a concern for me.

[SamuriHL]

I think you misunderstand a few concepts. So let's clear this up.

1) DVD's do not use bus encryption. You can always make ISOs of those that will "just work"
2) SOME blu-rays have bus encryption. If you have a bus encrypted disc, see below for why you CAN NOT make a straight ISO and expect it to work. You need LibreDrive
3) UHD's ALWAYS have bus encryption. You must use LibreDrive or a UHD friendly drive to defeat bus encryption here.

So why is bus encryption a problem? When bus encryption is enabled, a read data key (RDK) is established for the disc and drive combination. If you do not disable bus encryption, when you use DD or ImgBurn or whatever else, the bus encrypted data is not decrypted. And can never be decrypted without the RDK. So essentially, your ISO is encrypted garbage at this point. LibreDrive disables bus encryption so that the drive sends unencrypted encrypted data (lol that was funny...what it means is it sends the data that's stored on the disc as it is, which is AACS encrypted, rather than encrypting that with bus encryption as well). Hope this helps!

[Anuskuss]

so that the drive sends unencrypted encrypted data

Ah okay, so that means just simply replacing the files in the ISO filesystem with those from the MakeMKV decrypted directory will still not be perfect either because those are fully decrypted, as opposed to being AACS-encrypted (perfect) and additionally bus-encrypted (dd without LibreDrive).

Well hopefully someone writes a tool someday that can decrypted those doubly-encrypted ISOs with the RDK. Interestingly enough LEAWO Blu-ray Player CAN play that ISO (without supplying anything else). Maybe that protection is not so secure after all...

[SamuriHL]

so that the drive sends unencrypted encrypted data

Ah okay, so that means just simply replacing the files in the ISO filesystem with those from the MakeMKV decrypted directory will still not be perfect either because those are fully decrypted, as opposed to being AACS-encrypted (perfect) and additionally bus-encrypted (dd without LibreDrive).

Well hopefully someone writes a tool someday that can decrypted those doubly-encrypted ISOs with the RDK. Interestingly enough LEAWO Blu-ray Player CAN play that ISO (without supplying anything else). Maybe that protection is not so secure after all...

There are ways to extract the RDK and then aacslib can use it to decrypt it but this is not a simple thing to accomplish. But you'd need the original disc and drive that the ISO was made on in order to extract the RDK. Once it's extracted and put in the proper folder/file format anything that uses aacslib would be able to decrypt it.