Possible to create a decrypted backup from an encrypted ISO?

[DoctorHorsey]

This is not an answer to your question, I just wanna add something here, in case others find the way here searching for a solution to my own problem.

I, too, am currently trying to back up (DVD) discs with errors, and I'm using ddrescue to work around MakeMKV's limitation in that it won't skip errors.

I am on macOS (Sonoma), and I assume that what I'm describing here is macOS-specific.

I initially thought the reason I couldn't mount or open an ISO that was written during the first pass of ddrescue was because it was encrypted, so I went down this rabbit hole.

I turned out this wasn't the case — rather ddrescue still had a great deal more scraping to do (it skips not only bad sectors initially, but whole clusters), and important areas in the image were not yet copied.

Instead, what works for creating a non-encrypted ISO with ddrescue on macOS, is simply to first open the drive with VLC, and then read with ddrescue from the drive's raw block device rather than the buffered one. That is, if the DVD is mounted at /dev/disk10, then read from /dev/rdisk10 instead. You'll know when the drive has been unlocked, because reading from its raw device will fail with "drive busy" errors until it's been unlocked.