I am consulting here to find out how the content of a storage device can be erased so that it is not recoverable. When I say, that it is not recoverable, I do not mean that methods that are too paranoid are recommended, but rather, I hope that the data on the storage drive, cannot be recovered using traditional methods (software).
I have often used zero deletion, but I have read in a post that this method is not as safe as it seems.
Also on Hard Disks that I have to do the erasure, I have to check if the integrity of the surface is fine. For this I will use badblocks that records data and verifies it. Is it possible that the three badblock checks are sufficient for a secure erase?
Regarding Smartphone NAND Flash, I plan to use the following:
dd if=/dev/urandom of=/dev/name_partition/random.dd
Will it be enough for them to not be able to retrieve the information?
What do you recommend so that the erasure is safe in the different devices? Flash Drive, Hard Disk, Smartphone NAND Flash.
