Is it enough to make not recoverable all files after clean the free space with bleachbit ?

Forums: 

Hello!

I want to know something here: Is it %100 enough to make the all files (that the removed) not recoverable after we use bleachbit for all harddisk's free space? I know that there is no %100 not recoverable files for harddisks but my question is for SOFTWARE-BASED-RECOVER ? I mean if someone could recover the files with any software ( i mean without technical or physical recover ) ...

Also i want to ask if this process is useful for usb flash drives or SSD hard drives ?

Thank you!

The short answer is yes, it may be possible to use software methods to recover data from a storage device (hard drive or solid state) after the data has been deleted using standard methods (no overwrite) and the drive has been cleaned with the wipe-free-disk-space option. If anything can be recovered, most likely some bits of the data may be recovered from the slack space or swap file. On the other hand, this is difficult for "mere mortals" to do because the file allocation table (which tells where the file was) has been wiped and because the remaining pieces are probably small (especially in slack space). Also, if the original file was large (like a photograph or modern word processor document), the recovered data would probably not find large enough piece to be useful (depends on the type of file, though).

Depending on the specifics of the situation, there may be special recovery methods possible. For example, if you delete web browser history, then it can be possibly reconstructed from the Internet (from web server logs, government spying programs, etc).

Overwriting free disk space can be used on USB and SSD drives too, though the technology is new and evolving (compared to hard drives), so not as much research has been done on the effectiveness. (SSD are not "hard" except for hybrids, by the way). For now unless you are like Osama Bin Laden, you can generally assume that SSD and USB drives are like hard drives.

The best software method to wipe a primary drive (the drive that has the operating system) is to use DBAN with a single pass and with the option to wipe remapped sectors: this should make it 100% impossible to recover the data. You may want to read the documentation "Shred files and wipe disks". There are various steps you can follow to get you close to 100%.

---
Andrew, lead developer

Thank you for your interest.

You told me that it is possible to recover files (or let say a part of files) from the slack space or swap file... Except from these parts(slack space or swap file) it is possible to recover (by using software methods) some parts of the any file file (after wiped free space) ?

A normal person probably could not, but a very clever person may find a way in special cases (through a trick as the web log example above). Going forward, if you are paranoid you may consider methods mentioned in the link such as using whole-disk encryption using a system like TrueCrypt, so you won't ever need to wipe free disk space or worry about it.

---
Andrew, lead developer