In message <[email protected]> on Tue, 3 Apr 2018
12:52:50 +0000, "Salz, Rich" <[email protected]> said:
rsalz> I had not realized that we just increased the “entropy”
rsalz> requirements by 50%, from 256 to 384. The original DRBG
rsalz> submission that I did only required 128 bits. I think that is
rsalz> wrong, and I think the PR that did it (#5503) should be
rsalz> reverted.
rsalz>
rsalz> I am concerned that we are trying to meet requirements that we
rsalz> really don’t have. The original code was a huge improvement.
rsalz>
rsalz> Requiring 384 bits of random seed is silly. I think it is
rsalz> ridiculous. One way or another we HAVE to fix that before the
rsalz> release.
rsalz>
rsalz> Thoughts?
FYI, here's the magic number that lies behind this:
: ; git grep RAND_DRBG_STRENGTH
...
include/openssl/rand_drbg.h:# define RAND_DRBG_STRENGTH 256
The requirement change from 128 to 256 happened with this commit:
commit 32bda2b2e4900308cb025020d8c8692e1d3c2ba9
Author: Kurt Roeckx <[email protected]>
Date: Sun Feb 18 19:16:13 2018 +0100
Switch the DRBGs from AES-128-CTR to AES-256-CTR
Reviewed-by: Dr. Matthias St. Pierre <[email protected]>
GH: #5401
And then there's this one, which did the added 50%:
commit 2a70d65b99e1f2376be705d18bca88703b7e774a
Author: Kurt Roeckx <[email protected]>
AuthorDate: Sat Mar 3 23:19:03 2018 +0100
Commit: Kurt Roeckx <[email protected]>
CommitDate: Sun Apr 1 21:11:26 2018 +0200
Make sure we use a nonce when a nonce is required
If a nonce is required and the get_nonce callback is NULL, request 50%
more entropy following NIST SP800-90Ar1 section 9.1.
Reviewed-by: Dr. Matthias St. Pierre <[email protected]>
GH: #5503
Each of them seen by itself make sense. The combined result, though,
leaves me wondering...
(I'm tempted to try this with /dev/random only on Unix... do I
remember it right, that it blocks for a while after every 8 byte chunk
on some Unixen?)
--
Richard Levitte [email protected]
OpenSSL Project http://www.openssl.org/~levitte/
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