Re: [lamps] Adam Roach's Yes on draft-ietf-lamps-rfc5751-bis-10: (with COMMENT)

Adam Roach <> Tue, 03 July 2018 16:14 UTC

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To: Jim Schaad <>, "'The IESG'" <>
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From: Adam Roach <>
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Date: Tue, 3 Jul 2018 11:10:19 -0500
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Subject: Re: [lamps] Adam Roach's Yes on draft-ietf-lamps-rfc5751-bis-10: (with COMMENT)
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Jim --

Thanks for the quick response. Comments inline.

On 7/3/18 10:27 AM, Jim Schaad wrote:
>> §
>>>   The values to be placed in the micalg parameter SHOULD be from the
>>>   following:
>>>    Algorithm Value Used
>>>    MD5       md5
>>>    SHA-1     sha-1
>>>    SHA-224   sha-224
>>>    SHA-256   sha-256
>>>    SHA-384   sha-384
>>>    SHA-512   sha-512
>>>    Any other (defined separately in algorithm profile or "unknown" if
>>>              not defined)
>> The example then goes on to demonstrate the use of "micalg=sha-1".  This is
>> probably a misunderstanding on my part, but I thought that this document
>> was intending to mark MD5 and SHA-1 as historic for digesting content (cf.
>> §1.7 and §B.1). Wouldn't that mean they should be annotated as deprecated
>> in some way here? I would have also expected the example to use sha-256
>> or sha-512.
> In terms of the content of the table, this table is the only registry that exists for the values to be placed here.  This means that I have not removed any of the "historical" values as I believe that they need to be part of the table.

Sure; I didn't expect to see them removed. I expected them to be 
annotated in some way; something like:

   Algorithm Value Used
   MD5*      md5
   SHA-1*    sha-1
   SHA-224   sha-224
   SHA-256   sha-256
   SHA-384   sha-384
   SHA-512   sha-512
   Any other (defined separately in algorithm profile or "unknown" if
             not defined)

   *Note: MD5 and SHA-1 are historic and no longer considered secure.
    See section B.1 for details.

>    In terms of the following example, it is one of the examples that I did not re-generate as part of this document and thus is still setup with a micalg of sha-1.  While I could re-generate this example, it is correct as it is and has been validated.  I cannot have that same assurance if it is replaced.

I have a lot of sympathy for the challenges involved with generating 
correct examples. At the same time, I think it's  problematic to publish 
a document that deprecates an algorithm while simultaneously 
demonstrating its use. On the balance between these two factors, I think 
this document really needs to be updated so that the examples are 
consistent with the text.