Re: Real-time sound cyphering algorithm

From: Mike Amling (nospam_at_nospam.com)
Date: 05/29/05

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    Date: Sun, 29 May 2005 21:42:49 GMT

    David Eather wrote:
    >
    > I think this is the hard way to do this - a good way that will get a
    > perfect result, but still a hard way. The OP wanted to decrypt and
    > identify the sound by ear, so it doesn't have to be bit perfect.
    >
    > Encode the sound stream by adding (not xoring) the stream cipher
    > output.

       This is dubious. If you add white noise to a recorded conversation,
    it sounds like a conversation with tape hiss. Noise, which is what I
    presume a stream cipher would sound like, has to be overwhelming before
    a conversation becomes totally unintelligible.

    > Decode is just receive the sound (normalise it first) and
    > subtract the same stream cipher output. The result will probably
    > have bit errors in most bytes but still have the identifiable sound.

    --Mike Amling

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