From what I understand, even when data is overwritten on disk there is a possibility of it being recovered. From what I also understand, replacing/deleting a LUKS key is fast/trivial and does not lead to all the data being rewritten. This suggests to me that there is an important "secondary key" somewhere in the header, which further suggests that if a key has been compromised and replaced, but an attacker can recover a PREVIOUS state of the LUKS header that used that key, they could still access the data. Am I wrong or is this a security concern?