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Re: ESS 2.9 text

1998-02-24 08:32:27
Phil,

The contentHints syntax is being changed to replace DirectoryString with
UTF8String, so the DirectoryString syntax is no longer required in ESS.
However, your comment is still applicable because I believe that there will
be other fields that are constrained by MAX.  For example, I believe that
MLReceiptPolicy should be changed as follows:  

MLReceiptPolicy ::= CHOICE {
  none [0] NULL,
  insteadOf [1] SEQUENCE SIZE (1..MAX) OF GeneralNames,
  inAdditionTo [2] SEQUENCE SIZE (1..MAX) OF GeneralNames }


The PKIX X.509 Certificate and CRL Profile (aka PKIX I) includes:

"Appendix C. ASN.1 Notes

The construct

       SEQUENCE SIZE (1..MAX) OF

appears in several ASN.1 constructs. A valid ASN.1 sequence will have
zero or more entries. The SIZE (1..MAX) construct constrains the
sequence to have at least one entry. MAX indicates the upper bound is
unspecified. Implementations are free to choose an upper bound that
suits their environment."

Recommend that the MAX text in section 2.9 should be deleted.  Recommend
that the aforementioned excerpt from PKIX I should be included as a comment
in the ESS ASN.1 module.  This will ensure consistency between the PKIX and
S/MIME specs.

================================
John Pawling   
jsp(_at_)jgvandyke(_dot_)com                             
J.G. Van Dyke & Associates, Inc.           
================================


At 09:36 AM 2/24/98 -0500, asn1(_at_)mindspring(_dot_)com wrote:
Hope this has not already been mentioned.

The text in 2.9 ...

The construct "SIZE (1..MAX)" is used in the DirectoryString 
syntax to constrain each CHOICE to have at least one entry. 

could be improved by changing the second line to read...

notation to constrain each choice alternative to contain
at least one character.  

The text following the above...

MAX indicates that the upper bound is unspecified.  
Implementations are free to choose an upper bound that 
suits their environment.

will create problems. If one implementor chooses an upper 
bound of 64 and sends a message to an implementor with an
upper bound of say 32, the message will fail to decode.

Implementors should be allowed to choose the upper bound 
that suits them for messages that they send, but should be 
prepared to receive messages of any length.

Phil
-- 
Phillip H. Griffin         Griffin Consulting
asn1(_at_)mindspring(_dot_)com        ASN.1-SET-Java-Security
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