Well, it runs on Android? And you can compile your own kernel, and install google apps (or even run it in an emulator, anyway)... so... game over (wrt access to whatever is written to disc (or ram...))...
Unless there are COW mechanisms in place, simply pulling characters from /dev/{,u}random and scribbling over the original file should work well enough for the purpose of overwriting after the 10 second window.
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I wonder if you'd even have block level access to storage to pull that off through mobile APIs?
Well, it runs on Android? And you can compile your own kernel, and install google apps (or even run it in an emulator, anyway)... so... game over (wrt access to whatever is written to disc (or ram...))...
Unless there are COW mechanisms in place, simply pulling characters from /dev/{,u}random and scribbling over the original file should work well enough for the purpose of overwriting after the 10 second window.