Subject: Re: [Ntp] WGLC for draft-ietf-ntp-mac

From: Harlan Stenn <[email-masked]>
Date: Thu, 1 Mar 2018 04:57:13 -0800

On 2/28/18 5:51 AM, Daniel Franke wrote:
> The block size of AES is 128 bits, regardless of whether a 128- or 256-bit
> key is used, and therefore the output of AES-CMAC is always 128 bits.
> 160-bit digests are already supported by RFC7822, but there's no way to
> make AES-CMAC produce one.

OK, thanks - this is what I get for reading things in a hurry.

Is this even an issue then?  The reference implementation has long
supported any digest algorithm provided by the crypto libraries it was
linked with.

OK, it is an issue in that AES-CMAC is not a digest that is provided by
OpenSSL - we have to do use a wrapper to get the signature.

H
--
> On Feb 28, 2018 7:47 AM, "Harlan Stenn" <[email-masked]> wrote:
> 
>> Most everybody seems to think that 160 bits of digest is all that will
>> ever be needed.
>>
>> I'm perfectly happy making sure longer digests are supported.
>> -- Harlan Stenn <[email-masked]>
>> http://networktimefoundation.org - be a member!
>>
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> 
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-- 
Harlan Stenn <[email-masked]>
http://networktimefoundation.org - be a member!