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?
dd is neither the best nor a suitable method (dd is a scalpel not a shovel, use cp or cat). But optical media are tricky either way, with purposedly placed reading errors and stuff. redumper was made for a disc preservation initiative. Does a good job so far for me, but best to use old SATA drives with it. Those between 2010 and 2015 (pre-DRM-crackdown) also don’t need libredrive.