ubuntu-phone team mailing list archive

[Robert Park <robert.park@xxxxxxxxxxxxx>]

On Wed, Jul 17, 2013 at 5:38 PM, Dmitrijs Ledkovs <xnox@xxxxxxxxxx> wrote:

> I think Robert simply made a geeky joke here:
>
> >>> for SMS you could do unix ROT 13 a few times
> >>
> >> The NSA recommends doing it precisely 28 times for unbreakable security.
>
> Since ROT13 is a simple Caesar cipher, no amount of rounds improve
> it's security and one can easily and fairly quickly break it, even
> using pen and paper.
>

Oh, but it's much worse than that! Unlike most ciphers, the act of
*applying* rot13 is equivalent to *reversing* it. It's symmetrical in this
way. So if you apply it an even number of times, the end result is equal to
what you started with. Applying it 28 times has no effect, and applying it
27 times is indistinguishable from applying it once.

Alan was the one who said it could be applied "a few times", so I was just
running with that obvious joke and taking it to the next level.

Clearly, hilarious.