Re: RNG in a Smart Card

geeman@best.com
Thu, 16 Jul 1998 20:00:47 -0700

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Some designs I have seen use a reasonable amount of entropy, which IS by
the way available thru various tricks of the card interface, and then
leveraging certain crypto modules already present in a nontrivial way to
produce a not-very-breakable RNG.

At 11:32 AM 7/16/98 -0500, Bruce Schneier wrote:
>At 11:15 PM 7/16/98 +0800, Ng Pheng Siong wrote:
>>Hi,
>>
>>(Attempting to draw another thread on randomness...)
>>
>>Some smart cards, like Schlumberger's CryptoFlex, can generate keys
>>within the card. (Which others?)
>>
>>The question is: how does a smart card harvest entropy to generate "good"
>>random numbers? There aren't UI events, network packets, etc.
>>
>>If the entropy comes from sampling electrical noise, or whatever, what does
>>physics tell us about the constraints on parameters like sampling rate,
>>quantifying entropy, etc., in the context of operating within a smart card?
>
>My guess is that they use a very breakable random number generator.
>
>Bruce
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