Eraser - Secure delete files / free space

When you delete a file, the operating system does not really remove the file from the disk; it only removes the reference of the file from the file system table. The file remains on the disk / thumbdrive / flash / iPod until another file is created over it, and even after that, it might be possible to recover data by studying the magnetic fields on the disk platter surface. Before the file is overwritten, anyone can easily retrieve it with a disk maintenance or an undelete utility.

What secure erasing software does is to overwrite the files or the free space with a stream of meaningless pseudorandom data. Many government and industry standards exist for software-based overwriting that removes the data like the Peter Gutmann's Algorithm.

Eraser is an advanced security tool for Windows which allows you to completely remove sensitive data from your drive by overwriting it several times with carefully selected patterns. Eraser is a free software and its source code is released under GNU General Public License.

Even though the data in the files are erased securely, the list of file names would still be retrievable since the MFT (Master File Table) of the drive continues to keep the names in it. The MFT is actually an array which expands continuously and cannot be deleted. This is not removed even when a drive is formatted. Most of the disk wiping software does not modify the MFT, whereas Eraser substitutes all the file names with something like ZZZZZZZZZ.ZZZ or 000000.000 which makes any guessing of the contents impossible.

Download Eraser

For those who do not have necessary rights, there's Eraser Portable.  It is a repackaged version of the popular Eraser utility designed with portability in mind, so it has all the same great features of Eraser, but there's nothing to install.

Download Eraser Portable

Eraser portable has some issues like the configuration does not get saved if the user does not have administrator rights. Use EraserDrop as an alternative.