bogus random entropy sources
Posted Oct 6, 2010 3:51 UTC (Wed) by jzbiciak
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In reply to: bogus random entropy sources
Parent article: Solid-state storage devices and the block layer
I linked this whitepaper above on the technique VIA used on its C3. They used multiple free-running oscillators to gather entropy. The resulting output varies in quality, from 0.75 to 0.99 bits of entropy per output bit, depending on the decimation factor used and whether or not you enable von Neumann whitening.
Given that it generates entropy in the megabits/second range, this is several orders better than you can get from hard disk seeks and user keystrokes, even if you have to throw most of the numbers away. And, given the high apparent entropy of the raw bits, you don't really need to throw many away at all.
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