Now a days we hear lot of stories about identity theft, data theft and personal information lifted from discarded storage devices. If you are selling, recycling or discarding your device make sure you wiped out / erase your hard disk properly.
To understand how this works lets discussed about File Deletion, Disk Erase and Disk Wipe out first.
What is File Deletion?
When we store file in hard disk it creates entry (reference point) in MFT (Master File Table) to actual stored file. Now if we delete file its delete that file entry (reference point) from MFT index. Actual file still remains in hard disk. Windows is reluctant to overwrite the space on the hard drive where the files stores. However after deletion windows can use that space for other files. That’s why it’s relatively easy to retrieve deleted files.
Format Disk: Only create new FAT (File Access Table) and root tables, leaving all previous data on the disk untouched.
FDISK: Only cleans the partition table and does not touch anything else.
What is disk Erase?
Disk erase securely delete All Data. In this process all data wiping overwrites all data space on a storage device, replacing useful data with garbage data. Each disk erase utilities use different method to erase the data. Some fill space with zeros, some replace with zero first time then OxFF, Ox96 etc. to make sure there is no trace of actual data.
What is disk wiping?
In this process all Unused Data is removed. It works almost same way as disk erase. Although writing zeros across the disk is not sufficient to meet government data wiping standards such as DoD 5220.20. Securing wiping provide extra level of security by three passes of overwriting with special numeric pattern and verification.
Disk Erasing / Wiping Tools:
Some popular disk erasing tools are following.
Eraser makes it very easy to securely delete files, folders, or both. It overwrites the files being deleted with random data. There are several options for the number of times the files being deleted are overwritten with random data, including two versions of the US DoD 5220.22-M standard (3-pass and 7-pass) and the Gutmann method, which overwrites the file with random data 35 times. Can be downloaded from http://download.cnet.com/Eraser/3000-2092_4-10231814.html?tag=mncol;4
Darik’s Boot and Nuke (DBAN) is free erasure software designed for consumer use. DBAN users should be aware of some product limitations, including:
DBAN is a self-contained boot disk that automatically deletes the contents of any hard disk that it can detect. This method can help prevent identity theft before recycling a computer. It is also a solution commonly used to remove viruses and spyware from Microsoft Windows installations. DBAN prevents all known techniques of hard disk forensic analysis. It does not provide users with a proof of erasure, such as an audit-ready erasure report. Can be downloaded from http://www.dban.org/.
Is free utility for securely erasing a hard drive. More importantly, this utility adheres to United States Department of Defense standards (DoD 5220.22M) for hard disk data removal.
Can be downloaded from http://download.cnet.com/Active-Kill-Disk-Hard-Drive-Eraser/3000-2092_4-10073508.html?tag=mncol;2
It’s a free utility for wiping data from a hard disk in a secure manner. Like Eraser, Disk Wipe includes a number of different algorithms, including DoD 5220-22.M, and Peter Guttman. The really nice thing about this utility is that it is portable, so you don’t have to install it to be able to use it. Furthermore, Disk Wipe works on more than just hard drives. It can also be used to securely wipe USB flash drives and SD cards. Can be downloaded from http://www.diskwipe.org/.
I love this software and almost using everyday this program that removes unused, temporary files from your system, cleans up your internet history and cookies, contains a tool for cleaning the registry, and even allows you to clean up files from applications installed on your computer. The latest version offers a tool for wiping the free space on your hard drive. You can wipe the free space on a hard drive or the entire drive, securely deleting all data on the drive. There are four options for specifying how many times the data will be overwritten. Can be download http://www.piriform.com/products.