I plan on returning a microSD card I purchased and that I have written personal data and files too that I do not want recovered if someone attempted to.
I understand that data can still be recovered even after a format. Is there a way to make it unrecoverable?
Overwriting the disk data can get rid of almost all data - you could use sdelete (windows) , or shred (for Linux) or format the disk and copy it totally full with random or generic data (Linux Distros?)
You need to be aware that if you are using software and there are bad sectors, it's conceivable for a small amount of data to be hidden in them which won't be overwritten regardless of what software you use.
For secure delete you can use SDelete by Mark Russinovich. SDelete is a command line utility that takes a number of options. In any given use, it allows you to delete one or more files and/or directories, or to cleanse the free space on a logical disk.
An example command line to securely delete the entire folder and its sub-directories is as follow:
sdelete –p 3 –s C:\Users\SuperUser\cache4
An example command to wipe the free disk space of your local dirve (system drive, another partition or hard-drive):
sdelete –p 3 –z C d:\
The above will not delete any files but will wipe previously deleted files and unused space in the hard-disk. The said command will wipe the free disk space in Drive C using 3 passes. If you rather use the default pass, you can simply enter the following command: sdelete –z C:
Tip: It’s recommended in wiping the free disk space after using the secure deletion command. This will allow SDelete to wipe also the previously deleted files. You can also enter a command to secure delete and wipe a free disk space but it’s only applicable to the entered path.
If you are under Windows Privazer is a secure deletion utility that claims to securely rease files in a non recoverable way
USB Flash Tools also claims todo the same.
Freecommander is a more complete and complex file manger that among many other functionalities also has builtin alternative file management operations like move, copy, delete. I believe it also supports secure deletion among them.
