[openssl-project] FW: [openssl/openssl] VMS: lower the entropy demand for this platform specifically (#5904)

Kurt Roeckx kurt at roeckx.be
Sun Apr 8 15:36:27 UTC 2018

On Sat, Apr 07, 2018 at 08:50:35PM +0200, Kurt Roeckx wrote:
> On Sat, Apr 07, 2018 at 05:55:14PM +0000, Salz, Rich wrote:
> >     > Because
> >     > 	- It is not clear we need to do so
> >     
> > >    That we need to do what?
> > 
> > Do FIPS compliant random numbers in this release.
> We will never have that in any release by default, like I already
> stated a few times.
> > Everything is a trade-off.  Please explain why you want AES256-CTR with a nonce, and why AES128-CTR with personalization (and/or a DF) is not sufficient.
> RAND_DRBG_set() takes 2 parameters: type and flags.
> Type can be:
> - NID_aes_128_ctr
> - NID_aes_192_ctr
> - NID_aes_256_ctr
> The only flag is RAND_DRBG_FLAG_CTR_NO_DF. When using a DF a nonce
> is required. When not using a DF the nonce is not used.
> We always use a personalization string.
> The requirements for not using a DF means that you need to use
> "full entropy", which is even more strict then when using a DF.
> Since we don't have a "full entropy" source, we can generate it
> ourself, but it would require the double amount of entropy, so 512
> bit. We have no code currently to do this, but there is an open
> issue about it.

This is actually wrong. When not using a DF, the seed length = 384
for NID_aes_256_ctr. So we would need 768 bits of entropy if we
don't have access to full entropy.


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