How to delete file permanently so that it is not accessible even with the help of a data recovery tool? The most trusted way is to shred its information using advanced data shredding algorithms like Zeros (1 Passes), German VSITR (7 Passes), Peter Gutmann (35 Passes) etc. For this, you need a good file shredding software like Kernel File Shredder. It renames the files and shreds them from the hard disk of the system completely.