[RFC 2/2] FIXME: initial implementation of GCM

[Stephan Mueller]

Am Montag, 5. August 2013, 17:13:13 schrieb Dmitry Eremin-Solenikov:

Hi Dmitry,

>On Mon, Aug 5, 2013 at 4:31 PM, Stephan Mueller <smueller at chronox.de> 
wrote:
>> Am Montag, 5. August 2013, 16:28:09 schrieb Dmitry Eremin-Solenikov:
>> 
>> Hi Dmitry,
>> 
>>>Hi Stephan,
>>>
>>>On Fri, Aug 2, 2013 at 6:10 PM, Stephan Mueller <smueller at chronox.de>
>>>
>> wrote:
>>>> Am Freitag, 2. August 2013, 11:14:15 schrieb Dmitry
>>>> Eremin-Solenikov:
>>>> 
>>>> Hi Dmitry,
>>>> 
>>>>>+void
>>>>>+_gcry_cipher_gcm_setiv (gcry_cipher_hd_t c,
>>>>>+                        const byte *iv, unsigned int ivlen)
>>>>>+{
>>>>>
>>>> The IV handling in GCM is a special beast. SP800-38D section 8.2
>>>> defines exactly two ways how IVs are to be constructed. The current
>>>> implementation seems to leave that issue to the caller. However, a
>>>> caller may not understand that there is a specific requirement on
>>>> how
>>>> to set up the IV.
>>>
>>>Thanks for the pointing to the issue. In my opinion, we should not
>>>mandate any special form of IV in setiv interface. IV block could  be
>>>already constructed by the caller according to the rules of
>>>SP800-38D.
>>>I might be wrong, but judging from quick glance on OpenSSL, Nettle or
>>>NSS, no library implements these IV requirements in basic interface.
>>>If that would be required by FIPS certification, we can probably
>>>extend API. However I don't think
>>>that basic setiv should have any additional complexity.
>>>
>> As I am working in that field of FIPS 140-2, I know that NIST has
>> some
>> change of heart in that area in recent times. If you leave it like
>> this, a successful validation is in question in the future.
>
>What would be your proposal?

Unfortunately, I am not entitled to a proposal as this would taint me 
although I would have some suggestions. :-(

NIST and their rules...
>
>>>I will probably add a note that to be fully compatible with NIST
>>>recommendations,
>>>one have to generate IV according to the specification.
>>>
>>>What do you think?


Ciao
Stephan
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