libredrive bypass bus encryption?

Discussion of LibreDrive mode, compatible drives and firmwares
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thetoad
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libredrive bypass bus encryption?

Post by thetoad » Mon Mar 04, 2019 9:09 pm

Not that it matters in the context of MakeMKV, but for discs I have that are scratched and unable to be fully read easily, bypassing bus encryption would be useful for making ddrescue images of them especially if one tries to read different portions on different machines.

mike admin
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Re: libredrive bypass bus encryption?

Post by mike admin » Tue Mar 12, 2019 12:59 pm

Yes. The moment you see "Using LibreDrive mode" message, bus encryption is disabled (for the current disc only!). You can even close MakeMKV and use dd or anything else to copy the files.

Note, that this has some drawbacks. Your drive would still report that drive supports bus encryption (as it is, LibreDrive code does not meddle with AACS) and some applications might think that sectors might need to be decrypted, while bus encryption was in fact not applied.

The disc would be in this state until you eject it.

thetoad
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Joined: Thu Jul 28, 2016 4:18 am

Re: libredrive bypass bus encryption?

Post by thetoad » Tue Mar 12, 2019 3:44 pm

this is very useful for trying to recover broken discs (where one might use multiple copies to fill in the blanks). Is it possible for you to add a command line option to makemkvcon to basically say ("insert libredrive, but don't do anything else) so I can then just use ddrescue.

i.e. today for DVDs my workflow is lsdvd /dev/dvd && ddrescue /dev/dvd NAME.ISO NAME.log this could be similar. (as you probably know, in the DVD case, lsdvd authenticates the disc for RPC2 drives enabling them to be fully read so the ISO can be then decrypted via CSS brute force decrypters (vlc will play it as is), though it doesn't quite help for small VOB files as dont have enough data to brute force the CSS, but in practice those don't matter so much)

mike admin
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Re: libredrive bypass bus encryption?

Post by mike admin » Fri Mar 15, 2019 1:54 pm

thetoad wrote:
Tue Mar 12, 2019 3:44 pm
Is it possible for you to add a command line option to makemkvcon to basically say ("insert libredrive, but don't do anything else) so I can then just use ddrescue.
"makemkvcon info" will do just that.

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