Re: One-Time Pads [was: Re: Help: Randomizing a List of Numbers]

From: Tim Smith (reply_in_group_at_mouse-potato.com)
Date: 07/21/04 

Date: Wed, 21 Jul 2004 17:17:24 GMT

On 2004-07-20, Alexander Mulligan <alexander@mail2america.com> wrote:
> You generate list of random numbers or strings and then encrypt a message
> using one of those strings/numbers for each character as it comes and
> never repeat the use of one of those strings then throw away the key.
>
> Is that right?

Right.

> Completely unbreakable (???)

Under certain assumptions. First, that it is used correctly (e.g., you
really do throw away the pad as soon as you use it). Second, that your
random key is indeed random.

> My solution to the insecurity of the internet is to send private
> communications in a letter hidden inside a package via parcel post.
>
> I just don't trust PGP or SSH or any of those other encryption schemes.

PGP is orders of magnitude more secure against a determined adversary than
letters hidden inside a package sent via parcel post.

...
> You sure could fit a lot of them on a CD.

Yes. Many people overestimate how rapidly the key would be used, and so
think distributing CDs would be a nightmare, but I think they are way off.

Checking my home machine, I see the following:

    Uptime: 7 days, 6 hours
    Traffic on eth0: received 274 Mbytes, sent 196 Mbytes

For my machine at the office:

    Uptime: 14 days, 22 hours
    Traffic on eth0: received 376 Mbytes, sent 75 Mbytes

Based on those numbers, and my guess as to how much of that traffic was
between my home and work, if I were to use a one-time pad to encrypt traffic
between home and work, one CD a month would easily cover it. One DVD would
probably cover a whole year.

A CD a month, or even a CD a week, would not be a distribution nightmare. 

-- 
--Tim Smith

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