File: png-dSIG-OID-proposal-20080905.txt

This proposal is a companion to the recently-approved dSIG chunk.

There is a need for countersigners to add comments.
A logical place to put such comments would be 

  signed-comment OBJECT IDENTIFIER ::= { iso(1) member-body(2)
          us(840) rsadsi(113549) pkcs(1) pkcs9(9) 7 }

and described under paragraph 11 of RFC-3852 [1], but there is no
definition of a signed-comment type there.

The IANA "Private Enterprise Number (PEN)" 1.3.6.1.4.1.31170 was assigned to
the PNG Development Group, and the specification of OIDs in a subtree
under that has been delegated to the PNG Development Group (see [2]).

For dSIG purposes, it is proposed to use 1.3.6.1.4.1.31170.1.
This will be at the top of a new subtree as follows:

   signed-comment OBJECT IDENTIFIER ::= {1 3 6 1 4 1 
     PNG(31170) dSIG(1) signed-dSIG-data(1) signedComment(1)
   unsigned-comment OBJECT IDENTIFIER ::= {1 3 6 1 4 1 
     PNG(31170) dSIG(1) unsigned-dSIG-data(2) unsignedComment(1)

Both types of comment have data type "PrintableString" as
defined in the ASN.1 Basic Encoding Rules (see [3]).

In the future, any other chunks needing to specify ASN.1 OIDs would
have their own subtrees under the PNG PEN, e.g., 1.3.6.1.4.1.31170.2
for a second chunk type.

References:

[1] R. Housley and Virgil Security, "Cryptographics Message Syntax",
RFC-3852, available at http://www.ietf.org/rfc/rfc3852.txt

[2] IANA, "PRIVATE ENTERPRISE NUMBERS", available at
http://www.iana.org/assignments/enterprise-numbers

[3] ITU-T Rec. X.680 (07/2002)Information technology -- Abstract
Syntax Notation One (ASN.1): Specification of basic notation,
available at
http://www.itu.int/ITU-T/studygroups/com17/languages/X.680-0207.pdf