Messages in this thread | | | Date | Wed, 25 Jul 2012 20:16:19 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 07/10] random: add new get_random_bytes_arch() function |
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On 07/25/2012 08:10 AM, Theodore Ts'o wrote: > Aside from whether it's better to do this step in > xfer_secondary_pool() or extract_entropy() ...
By the way, I looked at doing this in xfer_secondary_pool()... the problem there is that xfer_secondary_pool() is called exactly once per invocation of extract_entropy() and so there is no way to make it inject the same amount of material as it consumes.
One could put it in extract_entropy[_user]() and if you prefer I'll rewrite the patch to do that, however that code would look very similar to the one in extract_buf() -- pretty much the same code in the caller rather than the callee -- but would have the same downside with being processed on 10-byte chunks because the final buffer might be misaligned and/or partial. It would mean just running it once rather than twice per output datum, but I actually expected you would prefer the additional mashing and security margin.
-hpa
P.S. Anyone who have any insider info on when we can expect the SHA-3 selection? Switching to SHA-2 at this time with SHA-3 around the corner (and based on numbers I have seen, likely to be faster) seems a bit silly...
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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