To wipe the entire drive, all you have to do is wipe the spot that stores the encryption of K

That statement is correct under its theoretical form. If you can guarantee you can wipe the key, and no one had ever access to that block, you have wiped the disk.

I mean that if you have low-level disk access and got the right block copied somewhere, then you can take your time to crack the key, especially if password is weak.

##Recall Modern disk encryption works by using a combination of a key, which is of fixed length, protected by a user secret (e.g. the password). So the key is useless without the password and the password is useless without the key.

##The answer is To securely wipe the entire drive, two conditions must be met:

• Block containing key must never be readable by any entity except the encryption hardware (could be valid for SSDs supporting hardware FDE)
• Block containing the key must be physically, and not logically, overwritten

The second condition varies on controller implementation. Most SSDs are unsuitable for storing such sensitive data because the drive does not transactionally guarantee the wipe of a sector when you want to overwrite it.

The first is even more difficult to achieve, because it proves that the only effective FDE is the one made at hardware level where the key never leaves the device. By leaves I include going to RAM memory. E.g. BitLocker has a widely known vulnerability to hot reboot attack.

To wipe the entire drive, all you have to do is wipe the spot that stores the encryption of K

That statement is correct under its theoretical form. If you can guarantee you can wipe the key, and no one had ever access to that block, you have wiped the disk.

I mean that if you have low-level disk access and got the right block copied somewhere, then you can take your time to crack the key, especially if password is weak.

Recall

Modern disk encryption works by using a combination of a key, which is of fixed length, protected by a user secret (e.g. the password). So the key is useless without the password and the password is useless without the key.

The answer is

To securely wipe the entire drive, two conditions must be met:

• Block containing key must never be readable by any entity except the encryption hardware (could be valid for SSDs supporting hardware FDE)
• Block containing the key must be physically, and not logically, overwritten

The second condition varies on controller implementation. Most SSDs are unsuitable for storing such sensitive data because the drive does not transactionally guarantee the wipe of a sector when you want to overwrite it.

The first is even more difficult to achieve, because it proves that the only effective FDE is the one made at hardware level where the key never leaves the device. By leaves I include going to RAM memory. E.g. BitLocker has a widely known vulnerability to hot reboot attack.