Re: [keyassure] Opening issue #21: "Need to specify which crypto

[Nicholas Weaver <[e-mail]>]

On Mar 8, 2011, at 7:58 AM, Sean Turner wrote:
> I think I'm in this camp.  It's hard to use 2119-language for something that nobody can claim conformance to.  Somebody is still going to need to write a draft that says here's the SHA-3 alg, here's it's reference and we're updating the registry regardless so I think the draft could just as well do this:
> 
>   Value        Short description       Ref.
>   -----------------------------------------------------
>   0            No hash used            [This]
>   1            SHA-1                   NIST FIPS 180-3
>   2            SHA-256                 NIST FIPS 180-3
>   3            SHA-384                 NIST FIPS 180-3
>   4-254        Unassigned
> 
>   Applications to the registry can request specific values that have
>   yet to be assigned. Note that there is every intent to update this
>   registry when [SHA-3] is finalized.  Implementors are strongly
>   encouraged to support a flexible implementation strategy in order
>   to support an orderly migration to [SHA-3] shortly after this
>   registry is updated.

I still don't get why SHA-384 instead of SHA-512.  SHA-384 just seems silly to me: its no FASTER than SHA-512, it MUST be less secure than SHA-512, and the "every bit is sacred" zombie-idea in DNS needs its head lopped off: 16B larger hashes does NOT make a difference in DNS, especially for a single signature over a big blob of data.

(Not that I'm saying it should impede this group, I'm happing with the language above or similar, I just want to know why people want to use SHA-384 instead of SHA-512!)