On Mon, 24 Jan 2000 nathan.zook@amd.com wrote:
>Second, we need to check the correlation of the bits in the result, which is
>what Sandy is discussing. As I recall from the press, the RNG calculates an
>index into a 2^16 byte array of "true random data", which means that the
>data is skewed by the fact that they are sampling a sample, even if the
>index is truly random. Presumably, every system has the same array, so it
>should be possible to find out what the entries are and see how bad the
>effect is.
If that is really what the RNG does, then it's useless. What you describe
is equivalent to a normal algorithmic pseudo-random number generator.
The documents I've found on Intel's developer web site do not describe how
the random number generator works.
If the index is somehow "randomly" (not algorithmically) generated, then
there is no point in having an array of 2^16 bytes! You could just return
the index as your random number. So a large array implies an algorithmic
approach, which means the RNG will return little if any real entropy.
Entropy has to come from somewhere something unguessable. Thermal
fluctuations or quantum spin states (Stern-Gerlach device, anyone) work
well in theory. But there is a difference between theory and practice...
Dave
David Whysong dwhysong@physics.ucsb.edu
Astrophysics graduate student University of California, Santa Barbara
My public PGP keys are on my web page - http://www.physics.ucsb.edu/~dwhysong
DSS PGP Key 0x903F5BD6 : FE78 91FE 4508 106F 7C88 1706 B792 6995 903F 5BD6
D-H PGP key 0x5DAB0F91 : BC33 0F36 FCCD E72C 441F 663A 72ED 7FB7 5DAB 0F91
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