> Some time ago you needed multiple uncorrelated overwrites to hide your data.
You really didn't. It's a really persistent myth that there's some secret technique to recover overwritten data. For PC hard drives "blobby bits" has never been a thing. It might have been a thing on 1970s style 24" disc platters, but we're not talking about those.
No one has ever recovered data from a drive that's had a single overwrite of zeros - no software claims to be able to do this, no recovery service claims to be able to do this, there are no published papers that claim to be able to do this (there's one that gets an accuracy of 50%-55% per bit, ie useless).
Since the early 1980s a single overwrite of 0 has been sufficient to destroy data.
And if you're worried about a well funded government agency that has the money to spend on exotic techniques you can do a single pass with random data, or NIST 7 passes, or you destroy the drive.
You really didn't. It's a really persistent myth that there's some secret technique to recover overwritten data. For PC hard drives "blobby bits" has never been a thing. It might have been a thing on 1970s style 24" disc platters, but we're not talking about those.
No one has ever recovered data from a drive that's had a single overwrite of zeros - no software claims to be able to do this, no recovery service claims to be able to do this, there are no published papers that claim to be able to do this (there's one that gets an accuracy of 50%-55% per bit, ie useless).
Since the early 1980s a single overwrite of 0 has been sufficient to destroy data.
And if you're worried about a well funded government agency that has the money to spend on exotic techniques you can do a single pass with random data, or NIST 7 passes, or you destroy the drive.