Re: High Quality Random sources, was: Re: SecuriKey

["Stephen D. Williams" <sdw@lig.net>]

I was only commenting on the random source, not the rest of the 
discussion about what a particular keyfob does.  Most useful crypto is 
public-key, i.e. asymmetric encryption, but one-time-pad is a useful 
fallback since it really is unbreakable if you have a truly random source.

OTP absolutely requires that you share the OTP out of band, i.e. you 
twin a capture of random data.  Any transfer makes it as vulnerable as 
the transfer method.

sdw

tabris wrote:

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>On Sunday 11 January 2004 10:38 pm, tabris wrote:
>  
>
>>On Sunday 11 January 2004 7:39 pm, Stephen D. Williams wrote:
>>    
>>
>>>Impossible?  I think not.  Some "mechanical" devices do exhibit true
>>>random capability, especially when enhanced by algorithmic means.
>>>To wit:  http://www.lavarand.org/
>>>
>>>Let me know if you can prove their methods don't provide a true "high
>>>quality" random source.
>>>
>>>I'd like to see their code as a module with an automatic test to make
>>>sure that the random source is high quality.  In this case, that
>>>would mean making sure that the cap was not off the camera.
>>>      
>>>
Or, at least if it was that it was pointing at a Lava Lamp!

>>>sdw
>>>      
>>>
>>	just because it passes tests of entropy and probability doesn't make
>>it random. it just gets really really close. [hence pseudo-random]
>>Everybody knows that /dev/random isn't truly random (it's still a state
>>machine, dependent on a hash algorithm [chosen b/c they can take a
>>non-random source and make it 'LOOK' random], and you feed it with data
>>that is not totally predictable. BUT, there are still enough ways to
>>exploit it if you can control/influence the input). it just can pass
>>enough tests so that it can be used.
>>    
>>
>tere are devices such as this that I admit to not knowing of until now...
>  
>
>>	and that still doesn't answer the question of how one would use [such
>>a device] to 'generate a one time pad'. a one time pad must be
>>possessed by both parties that are communicating. and if you have a
>>secure channel to transmit an OTP, then you have one that can carry a
>>message as well (most commonly, an OTP is used with a time delay. there
>>is a single time when a secure channel is available. one [or both] of
>>the parties brings it with him/her when he/she travels.
>>
>>	so i'd believe that mebbe this Securikey could hold one... but, any
>>USB key-fob type device can.
>>    
>>
>Perhaps I should make an amendment. you could perhaps put a geiger counter 
>and cobalt or other radioactive source into a key fob... but i don't 
>think it would ever be considered 'safe' to carry.
>
>other sources may be available as well (i admit to not getting the time to 
>read the website until just now). doesn't look like it fits in a USB 
>key-fob yet tho.
>  
>
>>	I'm sure that someone else can be more knowledgeable on this than I,
>>but the general theory holds fast.
>>    
>>
>
>- -- 
>If it's worth doing, it's worth doing for money.
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