Remote server LUKS header backup.

remote-luks-header-backup.md

See: https://pig-monkey.com/2017/07/luks/
See: https://wiki.archlinux.org/index.php/Dm-crypt/Device_encryption#Backup_using_cryptsetup

sudo mkdir /mnt/tmp
sudo mount ramfs /mnt/tmp -t ramfs
sudo cryptsetup luksHeaderBackup LUKS_DEVICE --header-backup-file /mnt/tmp/dump
sudo chown UID:GID /mnt/tmp/dump
cat /mnt/tmp/dump | nc -l 127.0.0.1 20000
# on local machine
ssh REMOTE nc 127.0.0.1 20000 | pass insert -m HOST/luksheader
sudo umount /mnt/tmp
sudo rm -rf /mnt/tmp