Re: one time pads

From: Alun Jones [MS MVP] (alun_at_texis.com)
Date: 08/27/03 

Date: Wed, 27 Aug 2003 02:16:31 GMT

In article <20030826215534.25337.00000829@mb-m15.aol.com>,
pcportinc@aol.combatSPAM (PCportinc) wrote:
>I watched that PBS special on the Atom Bomb spies.
>They talked about one time pads used by the Soviets
>and said that even today's super computers cannot
>break the pad. is this true? if so, then even such simple
>methods as were used 50 years ago could still be used
>today and not even the NSA or the FBI would be able
>to figure out what the encrypted message is?

There are some considerable non-simple parts to this that make it rather
difficult to implement in practical terms. For one, each party has to
ensure that the OTP is kept secure. For another, the OTP must be generated
in a truly random fashion - unpredictable. For a third, the data
transmitted must be relatively short, or the pages of the pad turned
frequently, in order to avoid the key being guessed from frequency matching.
 Fourth, the pads must be shared - you do know that a secret ceases to be a
secret the moment it is shared, don't you?

I'm sure there are plenty more practical obstructions to the widespread
adoption of OTP.

>if so, why the need for RSA, Blowfish, 128-bit, PGP, TEA, etc.?
>The bad old Ruskies didnt use them, neither did the Germans in
>WWII, and if it wasnt for human error, their encrypted messages
>would not have been decoded.

If it wasn't for human error, OTP might be as perfect as you describe, also.
 Fortunately, perfection is not generally required - just "good enough".

Alun.
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Relevant Pages

  • Re: In need of an EllipticCurve example (jdk1.5)
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    (comp.lang.java.programmer)
  • Re: In need of an EllipticCurve example (jdk1.5)
    ... their one-time pads -- not the entire pads, ... Keep in mind that mere "random gibberish" is not enough: ... communicate a new batch of R.G. through some other channel. ... OTP wouldn't help on the second channel (infinite ...
    (comp.lang.java.programmer)
  • Re: One-Time_Pad
    ... The KGB used people sitting at typewriters to produce OTPs. ... > those obtained by other means, such as when the KGB used the same pads ... they would have had a genuine OTP system... ... opportunities for keys to be compromised. ...
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  • Re: research into modern computer-based one-time pad implementations?
    ... > pads on computers? ... First of all, as you may be knowing, for One Time Pads the size of the ... creating a good OTP involves hashing together pseudo ... and other popular compression programs, but I received 0 or negative ...
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