End-to-end encryption means that your message is encrypted and decrypted locally on your and your recipient's devices, using an encryption key that is known only to you and your recipient.
WhatsApp claims to have implemented the "open-source Signal encryption protocol" (which works as described above), but since WhatsApp's actual source code is ...
They can't read the messages.
I'd avoid the notion of "sharing with Facebook" as WhatsApp is Facebook. Instead I'd focus on what's used for advertisement targeting.
Here, metadata (data about the message, not it's content) that they are able to and already are collecting (e.g. who you're sending messages to and when) have been used for various ...
GPAC project support cenc-aes-ctr enc./dec. and probably also cbc too.
It may be what you're looking for:
MP4Box -crypt drm_file.xml movie.mp4 -out movie_encrypted.mp4
MP4Box -decrypt drm_file.xml movie_encrypted.mp4 -out movie_decrypted.mp4
The encrypted packet is actually referencing a subkey that is marked as encryption-capable.
Use --with-subkey-fingerprint to see them.
(The same PGP key or PGP certificate can in fact have multiple encryption-capable subkeys, so if the packet used the main key's ID, it would be ambiguous.)
Also, GPG itself can find the main key for you, when given the subkey ...
First let's find where your superblock backups are kept.
# mke2fs -n /dev/mapper/s9vault
Down at the bottom of this output, should be a list of the backups.
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208
Finally, restore the superblock from the backup, replacing block_number with the first ...
FDE, Full Disk Encryption, is not removed by roll-back. It is removed by decrypting the disk and deactivating the encryption tool or system.
It is a standard process and well documented.
The decryption process can take some time, as it reads all data for the entire disk, decrypts it, and then re-writes it to the disk in an unencrypted form.