How do i resize encrypted partitions?

I want to shrink my encrypted ext4 partition with KDE partition manager, but the minimum-, maximum- and the current size are the same value. How do I change that?

Shrinking is a risky business, make sure you backup everthing!

  1. shrink the unencrypted filesystem
  2. shrink the luks device
  3. shrink the partition
    Depending on the filesystem used, sometimes this already stops at step 1 since not every filesystem supports shrinken (f2fs comes to mind)

Another way to go would be to:

  1. fully backup the partition contents
  2. delete and recreate the partitions with the new size
  3. restore the contents