Published by Steve Litchfield at 8:12 UTC, August 25th 2010
Q. Is there a way to permanently delete information on my S60 phone? I have had several confidential documents and want to be able to electronically shred them after use, such that they can't later be recovered.
A. As you probably realise, when files are deleted on a computer or phone, their contents remain on the relevant disk, which is where your question comes in. If you mean your 'phone memory' (disk C:) then you shouldn't have any worries after deleting a file, since there aren't any widely available recovery tools to probe around in this memory. (Documents on memory card may be more vulnerable, since they can be mounted as external disks on desktop PCs)
Having said that, if you want to be absolutely sure that the bits and bytes can never be recovered, even by specialist phone security companies, it's easy enough to fill your free space on C: with something else, thus overwriting the relevant disk sectors. For example, set your phone camera to record video to 'Internal/Phone memory' and record until the disk gets full (usually a minute or two). Then delete this temporary video and you're done.
For smallish documents, even this isn't really necessary, however paranoid you are, since Symbian OS itself is always using extra, freed-up disk space for its own needs and the chances of your bits and bytes hanging around for long are slim.
(This original text of mine was originally published in Smartphone Essentials magazine and re-purposed here with kind permission)