Rockbox Development > Feature Ideas

Encrypt and decrypt files

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torne:
Well, my point is that if you aren't at least reasonably careful then people won't need any specialised software to do it; an undelete program will suffice :)

All I'm saying is that there are steps you can take to mitigate this effect and you should probably consider doing so, I'm not saying it's a bad idea to have such a plugin. The most obvious one is to overwrite the contents of the plaintext file with zeros up to its full length, and make sure those writes have been synced to disk, before deleting it. This is pretty secure/safe on hard disks, and is good enough for flash if you only care about software trickery.

gbl08ma:
"undelete program" = specialized software, specialized in undeleting files ;)

I know that overwriting the area of the hard disk where the file was contained will higher the possibilities of having the old bits recognized by software; does this also happen on flash memories? I don't really know how random access memories work, but as they are random, won't the zeros go elsewhere in the memory (as it is random) instead of overwriting the specific position on the memory where the file was before?

torne:
That's not what random access means; random access means that any part of the media can be accessed at any time, rather than being forced to access it in a linear sequence.

While it's true that flash media will often relocate data blocks, such that overwriting data doesn't really overwrite it, this isn't *visible* to the OS. The remapping is handled inside the flash device or its driver, and so there is no easy way to retrieve the old data; it can only be recovered by accessing the flash memory directly, which is often impossible without physically taking the media apart (though sometimes it can be done with undocumented commands). An undelete utility or similar tools cannot retrieve data from flash in this way, even if it was there.

gbl08ma:
Thanks for the clarification :)

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