This will not stop a determined adversary from recovering the deleted files through forensic examination of the free space on the drive, even if you use a "secure trash" feature that overwrites the files, since they have probably been written to multiple locations on the disk. A full disk wipe (like with DBAN) is much safer, but that also has problems due to reallocated blocks and such. The best software based data erasure method is to use full disk encryption and overwrite the key if necessary. See this analysis. http://dkn255hz262ypmii.onion/index.php?topic=99520.msg699299#msg699299