[cryptography] Hardware Randomizer (SE Android)

Jeffrey Walton noloader at gmail.com
Sun Mar 4 20:12:17 EST 2012


Hi All,

I've been reading SE Android's Mobile Capabilities Package
(http://www.nsa.gov/ia/_files/Mobility_Capability_Pkg_(Version_1.1U).pdf).
I'm interested in seeing how the NSA collects entropy and produces
bits.

So far, the only item of interest is a "hardware randomizer" mentioned
in section 4.4.4. Thinking about it, I'm not sure what a "hardware
randomizer" is. Hardware randomizer seems a bit non-standard to me - I
see a discussion of the linux kernel and PIIIs for a hardware
randomizer [1] from Indiana University, and a IC for a hardware
randomizer [2].

Does this thing produce random bits like like a hardware based RNG
(similar to Entropy Key (http://www.entropykey.co.uk/))? Does it feed
/dev/[u]random? Or does it take bits from /dev/[u]random, add a secret
sauce, and produce an output stream pseudo random bits?

Jeff

[1] http://lkml.indiana.edu/hypermail/linux/kernel/9910.1/1254.html
[2] rf.harris.com/media/Acropolis_tcm26-9013.pdf



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