How to permanently delete file so that it becomes unrecoverable?

Question

If I want my application (written in .NET) to delete a file such that it can not be recovered by disk recovery tool. What are my options?

One that I can think of is that I open it up in write mode, overwrite all of it with some random data and it would make the file unrecoverable. Is there any other way?

Answer 1

Shell out to SDELETE: http://technet.microsoft.com/en-us/sysinternals/bb897443.aspx

you can specify the number of passes.