using SRAM state as a source of randomness

Ivan Krstić krstic at
Sun Sep 16 12:35:20 EDT 2007

On Sep 12, 2007, at 7:06 AM, Udhay Shankar N wrote:
> Sounds like an interesting idea - using SRAM state as a source of  
> randomness. Any of the folks here willing to comment on this?

If you care about your randomness, you don't want to be making the  
assumption that a source is random because "it sometimes looks that  
way, sort of". You want to be using a source that's assumed random  
because, as far as you know, it's very hard for it to be any other way.

Clearly, SRAM state falls into the former category, and there are  
lots and lots of variables keeping it firmly outside the latter. This  
means the usual wisdom applies: if you really need the extra entropy,  
mix some of these SRAM state bits into your pool, but make sure  
you're also feeding the pool from at least one source about whose  
randomness you can reason strongly.

Ivan Krstić <krstic at> |
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