Secure Deletion Private Data: Tips And Tricks For Windows

Most people have some data that they would rather not share with others - passwords, personal information, classified documents from work, financial records, self-written poems, the list can be continued forever. Perhaps you have saved some of this information on your computer where it is conveniently at your reach, but when the time comes to remove the data from your hard disk, things get a bit more complicated and maintaining your privacy is not as simple as it may have seemed at first.

Normal file deletion is insecure!

Your first thought may be that when you delete a file, the data is gone. Not quite, 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 as long as 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.

For example, imagine that you have been surfing on the web for a while and afterwards wish to clear any traces revealing what sites you visited. You go to your browser’s preferences and select to clear the cache and the history file, the information is now gone you think to yourself - well think again. The browser cache files can easily be restored with an undelete utility and your privacy is once again compromised.

To be sure that a file is gone, its contents must be properly overwritten before deleting. As simple as it sounds, there are several problems in secure file removal, mostly caused by the construction of a hard disk and the use of data encoding. These problems have been taken into consideration when Eraser was designed and because this intuitive design you can safely and easily erase private data from your disk.

You have most likely already insecurely deleted countless amount of files from your drive and every now and then applications create (and insecurely delete) temporary files on your drive containing some possibly sensitive data that you would rather not share with other people. This data remains on your drive until it gets overwritten and can be viewed with simple disk utility.

This is where the erasing of unused disk space comes in handy. The erasing of unused disk space means that all space available on your drive will be overwritten so that data previously saved on it cannot be restored. Eraser provides you a convenient way to erase the unused disk space regularly in order to remove the remains of temporary files and other sensitive information you possibly have had on your hard disk.

By now you must be wondering what exactly does this program do to my computer when erasing files. You have come to the right place, the procedures gone through when erasing files are explained here.

After determining the file type (files compressed or encrypted at the file system level are supported on Windows NT and 2000, but Administrator privileges are required for low-level disk access), Eraser needs to determine the size of the file. When calculating the size, the cluster tip area is included so the data stored on it will be erased too.

Once the size is calculated, the file will be overwritten with the selected method. Eraser takes care of flushing write buffers to make sure that the data really gets written to the disk and is not only saved in a buffer somewhere. If the overwriting was successful, the final step is to properly delete the file.

Before removing the reference of the file from the file system (standard delete), the file will be truncated to zero length to clear traces of the allocated clusters, the filename will be overwritten (if selected) and finally file dates (creation, access, modified) will be scrambled to complete the file erasing.

About the Author

Author is founder of Open Source Security Tools site. Visit our site to learn more about free file removal tool.