That depends on who is accessing your computer. If a goverment-style organization is accessing your computer and seeking long enough, they might find even that out (on some drives, you even need to override your data several times to remove it entirely). Using “entropy” means you have to use some form of RNG. If you do that, you need a way to get rid of this entropy to access the data. And as you can access the data (somehow), other people can do that as well. Hiding stuff never gives you absolute security, but it can give you more security.