I want to create a bit-by-bit backup of my DVD and a Blu-ray disc without removing its encryption. Is dd be the best method, and if so, what flags or settings should I use? Also, is comparing the SHA-256 hash of the generated ISO file with the hash of the original disc’s raw data (read from /dev/sr0) the best method for verifying the backup’s integrity?

  • Majestic@lemmy.ml
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    1 hour ago

    This is silly. You’re approaching this with wrong-headed thinking. Just use makemkv.

    What you will have if you used hacked firmware to bypass physical anti-copying methods present on BluRay discs to actually get a bit for bit copy of your disc is a useless blob of encrypted data that you have no way of verifying for accuracy (that it was copied correct or that the disc itself didn’t have subtle physical damage which gave you something damaged because you can’t play it to verify) and which you have no way of using. You’ll have no way of ripping it or turning it into usable data in future if your disc does go bad because no one else uses this method so there’s no software that will allow you to turn this encrypted blob easily back into a playable movie and to burn it to a new BluRay writable disc would break laws anyway because you’re engaging in duplication and secondly all BluRay authoring (burning) programs are built around building and burning unencrypted video files to a disc not around burning an encrypted blob to a disc (often specific sectors containing specific data must be written to specific parts of the disc to make it playable, something no public program will help you with when trying to bit for bit copy in reverse and which blindly bit for bit copying at low level isn’t likely to achieve).

    Everyone else breaks the encryption and dumps a copy of the disc including the AACS keys and certs to prove ownership and you should do the same rather than thinking you’re particularly special or vulnerable. If you’re that much an enemy of the state or media companies they’ll do you just as much for having the encrypted copies and state you had INTENT to break it (and indeed defeated DRM mechanisms on the drive firmware itself first which may be a violation of law in order to get that copy) if they’re trying to make an example out of you because you’ve pissed them off.

    In practice no media company is likely to go after someone breaking the encryption while retaining the discs and keeping the copies only for themselves. There’s simply no incentive to harassing paying customers in that way if you’re not uploading the contents or hosting a for-profit Plex or Jellyfin server of the contents or burning bootleg copies of the films. You’d have to go around publicly bragging in your own name about breaking the encryption and pretty much dare them to get you for them to know or care enough to do anything about it short of you otherwise breaking the law as I outlined above.