Permanently delete a file on internal / SD card storage?

[czissman]

Hi...

Is there an app that will permanently delete a single file on an Android phone's internal storage and/or SD card so that it's not recoverable? I have a file that contains personal data and I want to delete it, but I want to do so in a manner that will keep anyone who finds (or steals) my phone from being able to recover it.

Also, does Android have the equivalent concept to the Windows Trash where files are temporarily stored until permanently deleted? If so, where is this?

Thanks!

 

[sitlet]

Astro File Manager can be used to delete files. Since both the internal memory and the sd card are flash memory, there is no residual data once a file is deleted, unlike hard drives.

 

[tcat007]

You probably want something like this, but it's too new to know if it's any good (or safe or necessary). My File Shredder - Android app on AppBrain

 

[alostpacket]

(I think) it depends on the flash mem controller. Some will mark for deletion, some will mark available to overwrite.

You can recover data theoretically (like a magnetic drive), but Flash drives do work a bit differently.

If you really want to get into the nitty gritty of it, Anandtech has a few great write-ups on SSDs. In the articles they talk a lot about how Flash memory works (same basic tech behind SDcards).

AnandTech - The SSD Anthology: Understanding SSDs and New Drives from OCZ

Basically I think the app would have to overwrite the block and/or page. And Android (java) apps aren't generally given access to that kind of low level disk IO (as far as I know).