Compared to HMAC, KMAC and ASCON, AES-CMAC is more widely supported in many 
MCUs due to the fact that no extra primitive technologies except AES is 
required.

So for the embedded world e.g. automotive, supporting AES-CMAC in COSE is 
wished.

Lijun

> On 31. Oct 2025, at 18:25, Robert Moskowitz 
> <[email protected]> wrote:
> 
> You have HMAC, KMAC, and ASCON.
> 
> You want lightweight?  Go with ASCON.
> 
> HMAC is two keyed MACs, KMAC is one.  HMAC can be lighter in memory with KMAC 
> faster.
> 
> I generally run away from AES-CMAC.  It has edge cases where there be 
> dragons.  Thus it has been years since I have don't anything with CMAC.
> 
> On 10/31/25 12:55 PM, Sipos, Brian J. wrote:
>> WG,
>> In doing some background research for a minimalist COSE profile I ran into 
>> the case that the existing registered AES-MAC algorithm family is not on the 
>> US NIST FIPS 140 approved list [1] but the AES-CMAC family is approved. I 
>> saw some COSE discussion on this going back to 2015 [2] and 2018 [3] with 
>> the conclusion there that AES-CBC-MAC was more widely supported in 
>> constrained environments. Since that time, it appears that CMAC has been 
>> more solidified as the preferred cipher-based MAC technique.
>>  
>> Is there any COSE WG appetite for registering a FIPS-approved AES-CMAC 
>> algorithm family? This would be a relatively small addition, probably two 
>> code points, and because this is not a technical or security limitation of 
>> the existing AES-MAC registrations I think they would be left in-place and 
>> not deprecated.
>>  
>> I can bring this up at next week’s IETF if there is any interest.
>>  
>> Thanks for any feedback,
>> Brian S.
>>  
>> [1] 
>> https://csrc.nist.gov/projects/cryptographic-module-validation-program/sp-800-140-series-supplemental-information/sp800-140c
>> [2] https://mailarchive.ietf.org/arch/msg/cose/GwP_6EgbzTkzXGh36WhX0nomhT8/
>> [3] https://mailarchive.ietf.org/arch/msg/cose/yiLtOdsw6RXC-iHdNHJKGWgfUEs/
>>  
>> 
>> 
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