So I am trying to write a function, in C, that will securely erase a file. Here is my general procedure:
- Open the file for reading and writing
- Overwrite the file a specified number of times with random data, flushing the file with flush() after each iteration
- Deleting the file using remove()

If a file is overwritten, say 10 times, in this manner will it be securely erased or not??

That's in interesting approach to secure erase. If it'd work would depend on your filesystem, as some write data to a different location when it's being overwritten. This is why such secure delete functions usually write directly to the sectors on the drive where the file is located.

I had a feeling the strategy was a little too simple. I got the idea looking at the source code for an open-source utility that claimed to securely erased files. So I decided to try it out, but didn't really have a way to test it.

moghedien wrote:I had a feeling the strategy was a little too simple. I got the idea looking at the source code for an open-source utility that claimed to securely erased files. So I decided to try it out, but didn't really have a way to test it.

Does anyone know of some open source code, that properly securely erases a file, that I could take a look at??

I believe this works.

http://eraser.heidi.ie/

Thanks! I'll check that out.