Subject: [sidr] RFC 6487 possible oversight

From: Andreas Reuter <[email-masked]>
Date: Wed, 8 Oct 2014 15:50:20 +0200

Hi,

I came across a (possible) oversight in RFC 6487, Section 4.4 about
the issuer field:

>    An issuer name MUST contain one instance of the CommonName attribute
>    and MAY contain one instance of the serialNumber attribute.  If both
>    attributes are present, it is RECOMMENDED that they appear as a set.
>    The CommonName attribute MUST be encoded using the ASN.1 type
>    PrintableString [X.680].

This wording does not define the encoding of the serialNumber
attribute.

While mailing with Rob he told me that the serialNumber came later
into the spec, and most likely the definition has been just forgotten.
Can someone from the authors clarify?

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From: Sean Turner <[email-masked]>
Date: Wed, 8 Oct 2014 11:30:29 -0400

> Can someone from the authors clarify?

I think it’s right as is.

RFC 5280 has the definition for serial number:

-- Naming attributes of type X520SerialNumber

id-at-serialNumber      AttributeType ::= { id-at 5 }

X520SerialNumber ::=    PrintableString (SIZE (1..ub-serial-number))

So there’s no need to say it’s printable string because it always is printable string.  When you specify a common name you need say which of the permitted encodings you want because there’s a choice of 5 string types:

-- Naming attributes of type X520CommonName

id-at-commonName        AttributeType ::= { id-at 3 }

-- Naming attributes of type X520CommonName:
--   X520CommonName ::= DirectoryName (SIZE (1..ub-common-name))
--
-- Expanded to avoid parameterized type:

X520CommonName ::= CHOICE {
      teletexString     TeletexString   (SIZE (1..ub-common-name)),
      printableString   PrintableString (SIZE (1..ub-common-name)),
      universalString   UniversalString (SIZE (1..ub-common-name)),
      utf8String        UTF8String      (SIZE (1..ub-common-name)),
      bmpString         BMPString       (SIZE (1..ub-common-name)) }

spt

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From: Randy Bush <[email-masked]>
Date: Wed, 08 Oct 2014 12:01:55 -0400

> RFC 5280 has the definition for serial number:

while i am an advocate for references as opposed to redundancy in rfcs,
i gotta say chasing the refs in this corner of the universe makes me
even crazier than usual.

randy

---

From: Rob Austein <[email-masked]>
Date: Thu, 09 Oct 2014 17:44:50 -0400

At Wed, 8 Oct 2014 11:30:29 -0400, Sean Turner wrote:
> 
> I think it?s right as is.
> 
> So there?s no need to say it?s printable string because it always is printable string.

My bad, I didn't think to check RFC 5280.

I agree that the text in RFC 5280 nails it down to PrintableString and
that there's no need for a change to RFC 6487.