On Sat, 12 Nov 2016, Paul Wise wrote: > On Sat, Nov 12, 2016 at 1:26 PM, Johannes Schauer wrote: > > If you are just worried about GPG, then removing .gnupg should be all you > > need > > to do. > > Deleting files does not remove the data from the block device, it only > removes metadata.
It is pretty much impossible, short of using the secure erase features of an SSD and trusting it to implement that correctly -- or using undocumented SSD firmware bypass commands, which might not even exist in the first place, etc -- to get an SSD to really erase data from the RAW flash. > Even overwriting the block device does not necessarily remove them from an > SSD: In any SSD worth something, overwriting a sector will *never* remove the old data, as it will always be directed to some other flash block. It just schedules the old block for eventual garbage collection and erasure. Even trimming a sector won't erase the flash. The only thing that is supposed to work is to command the SSD to secure-erase itself, and that depends on the manufacturer doing its job right in the first place. Alternatively, using dmcrypt-based FDE, and trashing the encryption key will give you an erase level that is at least as strong as the strength of your passphrase. > I strongly suggest removing the SSD before sending the device. Indeed. -- Henrique Holschuh
