> then you would not be able to decrypt it without the correct key You're correct. So an attacker will now attempt obtaining the correct key, by targeting the

> then you would not be able to decrypt it without the correct key You're correct. So an attacker will now attempt obtaining the correct key, by targeting the pre-decryption stages and infecting any layer that has access to the decryption key. If the bootloader's the one that asks for the user for the disk decryption key, then the bootloader would be the prime target of infection. And so on, it's turtles all the way down, until the hardware; which is what gives Intel the excuse to ship locked down firmware with their processors and motherboards.