Quote Originally Posted by prasannaganesh View Post
hey just use any "Shred file" software. it destroys the file by overwriting random content.
...
then i come to encrypting the full logical volume,
i guess we dont want that much security to save our personal file.
just a password is enough.
For some hopefully useful information on shredding, please see www .gnu.org/software/coreutils/manual/html_node/shred-invocation.html. The link is about the shred command line tool, not any of the so many Windows free/shareware, but it has been referred here to throw some light on the concept of shredding. Having said that, the software I initially suggested (PGP) supports encryption of files and shredding of files too. However, as I said, information once created is not lost...the solution to choose depends upon how difficult you want to make it for someone to retrieve your data and how knowledgeable those who are trying to access it are.

Now onto why the logical volume (or better, the hard-disk) should be encrypted: do you think your personal file (assuming there is only one) exists only in one so-called place in your Windows file-system (of course, I am being naive in assuming you use Windows) and on your hard-disk? Once you open your file in various software (or even one software like MS-Word), it can exist in more than one place on your hard-disk. Depending upon how many times you opened it, it can have multiple copies on the hard-disk platter, though on the file-system, it may be in one-place only (i.e., after you have closed it, that too, hopefully, since MS-Word does not always delete its temporary work-files); or it maybe in multiple places which you may be completely unaware of.

Security is not as easy as it appears.

I think I have give some indication of what it means to guarantee your data is not accessible to anyone else. As my last statement on the topic, I would just say that I am not a security guru, so you can rely upon the fact there are persons out there who are not security gurus either (persons you are trying to protect your data from), but who know enough on how to retrieve data secured by a simple password - their target, e.g., can be not your password protected file, but the so many fragments lying here and there; and they can always attempt to brute-force their way in for a resource protected only by a password...