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Re: Comments to CMS-02

1998-01-06 01:16:35

-----Original Message-----
From: John Pawling <jsp(_at_)jgvandyke(_dot_)com>
To: ietf-smime(_at_)imc(_dot_)org <ietf-smime(_at_)imc(_dot_)org>
Date: Monday, January 05, 1998 07:24
Subject: Comments to CMS-02


IssuerAndSerialNumber should be changed as follows:

IssuerAndSerialNumber ::= SEQUENCE {
 issuer        Name,
 serialNumber  SerialNumber
 issuerAltName [0] IMPLICIT GeneralNames OPTIONAL}

This would be backwards compatible with PKCS #7, v1.5.


John,

Excellent point, but please bear in mind the following...

The issuerAltName extension is defined as a GeneralName not GeneralNames -
i.e. there is only one of them.  Unfortunately, if we simply change the
GeneralNames to a GeneralName, the IMPLICIT key word in the above would be
ignored by the ASN.1 compiler because of the following:

The GeneralName structure is a CHOICE, and under BER and DER all CHOICE
constructs that have additional tagging are tagged as EXPLICIT regardless of
any explicit IMPLICIT or EXPLICIT key word. (As in X.509's
AuthorityKeyIdentifier extension)

IMHO, I believe the following would make matching against issuerAltName
easier to implement:

IssuerAndSerialNumber ::= SEQUENCE {
  issuer        Name,
  serialNumber  SerialNumber
  issuerAltName [0] EXPLICIT GeneralName OPTIONAL}
                        -- EXPLICIT keyword is informational as GeneralName
is always
                        -- encoded explicitly.

Darren

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