Re: [xcbf] Discussion document on XCBF spec

[John Larmouth <j.larmouth@salford.ac.uk>]

I take your point on not using BASIC-XER, although I would prefer to use 
  "basic XER" if you are agreeable, to avoid confusion.

But your point b) unfortunately is not possible unless the Open Type is 
changed to an OCTET STRING.  Open types are *always* (in all encoding 
rules) encoded according to the same encoding as the outer-level encoding.

So even if you start with a CXER encoding (which indeed *is* a valid 
basic XER encoding), going through a PER relay can produce a non-CXER 
encoding (some other basic XER encoding, as there is no formal knowledge 
that it should be CXER), so the receiving application will need to 
decode and re-encode with CXER in order to check the signature etc.  But 
provided that is understood and clearly spelled out, this is a workable 
solution.

John L


Ed Day wrote:
> The combination we were closest to at the end was:
> 
> a) BASE64 for the CertificateSet and CertificateRevocationList OCTET
> STRING's
> 
> b) XER for the outer level encoding and CXER for the BiometricObjects (note:
> for the purpose of this document, the term "BASIC-XER" is not recognized
> because it does not exist in any published standard).
> 
> Regards,
> 
> Ed
> 
> 
> ----- Original Message -----
> From: "John Larmouth" <j.larmouth@salford.ac.uk>
> To: "Ed Day" <eday@obj-sys.com>
> Cc: "xcbf" <xcbf@lists.oasis-open.org>
> Sent: Wednesday, May 07, 2003 2:23 PM
> Subject: Re: [xcbf] Discussion document on XCBF spec
> 
> 
> 
>>A further reply:
>>
>>We have four options now (combinations of a) and b) below):
>>
>>a) Use of BASE64 or not for the DER encodings in the OCTET STRINGs
>>
>>b) Use of CXER or BASIC-XER as the outer-level encoding.
>>
>>It is my honest belief that clear conformant text can be produced for
>>all four combinations (but with very different imlications for the
>>complexity of implementations, particularly if relaying in and out of
>>PER is being envisaged - see an earlier e-mail).  I am prepared to
>>produce draft text for **any two** out of the four, but not for all
>>four!  You can then decide which you like best.
>>
>>Let me know which two you want text for.  (Noting that BASE64 is
>>currently in, but that the current text is ambiguous/inconsistent on b)
>>above.)
>>
>>Would a NetMeeting, once Paul is back from holiday and can host it, be a
>>useful way of resolving this, or do you want to try to settle it sooner
>>by e-mail?
>>
>>John L
>>
>>
>>Ed Day wrote:
>>
>>>It was my understanding from Phil that CXER could not be used for the
>>
> entire
> 
>>>message because the Base-64 encoded DER components would violate the
>>
> CXER
> 
>>>rules for OCTET STRING encodings.
>>>
>>>Regards,
>>>
>>>Ed
>>>
>>>----- Original Message -----
>>>From: "John Larmouth" <j.larmouth@salford.ac.uk>
>>>To: "Ed Day" <eday@obj-sys.com>
>>>Cc: "xcbf" <xcbf@lists.oasis-open.org>
>>>Sent: Wednesday, May 07, 2003 12:52 PM
>>>Subject: Re: [xcbf] Discussion document on XCBF spec
>>>
>>>
>>>
>>>
>>>>The document is currently inconsistent, Ed.  Do we intend CXER encoding
>>>>for everything excpet DER, or use of basic XER at the outer-level?
>>>>
>>>>I think minimum changes mean we do everything with CXER (and DER), and
>>>>remove any text that implies the opposite - probably only a sentence or
>>>>two, at most.
>>>>
>>>>I will produce a document to that effect in the next few days.
>>>>
>>>>John L
>>>>
>>>>Ed Day wrote:
>>>>
>>>>
>>>>>I think given this late date that changes should be kept to a minimum.
>>>>
>>>What
>>>
>>>
>>>>>is there has already been approved for the most part.  Only a few
>>>>
> tweaks
> 
>>>>>describing how the Base64 encoding is to be accomplished should be
>>>>>necessary.  I think any big changes need to be deferred to the next
>>>>
>>>version.
>>>
>>>
>>>>>Regards,
>>>>>
>>>>>Ed Day
>>>>>
>>>>>
>>>>>----- Original Message -----
>>>>>From: "John Larmouth" <j.larmouth@salford.ac.uk>
>>>>>To: <j.larmouth@salford.ac.uk>
>>>>>Cc: "xcbf" <xcbf@lists.oasis-open.org>
>>>>>Sent: Sunday, May 04, 2003 4:26 PM
>>>>>Subject: Re: [xcbf] Discussion document on XCBF spec
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>>To reply to my own message:
>>>>>>
>>>>>>John Larmouth wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>>I understand that you should be getting notification of that upload
>>>>>>>automatically, but it has not come back to *me* yet.
>>>>>>
>>>>>>It still has not come (but I understand that others have got it).
>>>>>
> Maybe
> 
>>>>>>the person posting the document does not get the noticiation?  But
>>>>>
> this
> 
>>>>>>is not the first time that OASIS mailings have taken a couple of days
>>>>>
> to
> 
>>>>>>reach me when others have got them (don't know why - guess the server
>>>>>
> is
> 
>>>>>>anti-English!).
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>>(There is no formal mechanism - even with Amendment 1 in place - to
>>>>>>>formally forbid a HEX encoding.  You can allow a BASE64 encoding as
>>>>>>
> an
> 
>>>>>>>encoder's option, but you cannot express formally that you require
>>>>>>>(only) that to be used instead of HEX.
>>>>>>
>>>>>>I got this wrong - getting too old!  The BASE64 encoding instruction
>>>>>>*does* prohibit use of HEX (otherwise we would have ambiguous
>>>>>>encodings), but it does NOT mandate BASE64 - use of XML mark-up for
>>>>>
> the
> 
>>>>>>contents is still allowed as an encoders option.
>>>>>>
>>>>>>Sorry for the wrong information.
>>>>>>
>>>>>>(I don't think this affects the main discussion on what we want for
>>>>>
>>>XCBF.)
>>>
>>>
>>>>>>John L
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>--
>>>>PLEASE NOTE - As an anti-SPAM measure, e-mails will shortly
>>>>not be accepted by my machine from an unknown sender unless
>>>>the subject contains the phrase "Hi John".
>>>>
>>>>If you pass my e-mail address to others (which I am very happy
>>>>for you to do) please tell them to include this phrase in the
>>>>subject line of their first mailing to me.  Thanks.
>>>>
>>>>   Prof John Larmouth
>>>>   Larmouth T&PDS Ltd
>>>>   (Training and Protocol Development Services Ltd)
>>>>   1 Blueberry Road
>>>>   Bowdon                               j.larmouth@salford.ac.uk
>>>>   Cheshire WA14 3LS                    (put "Hi John" in subject)
>>>>   England
>>>>   Tel: +44 161 928 1605 Fax: +44 161 928 8069
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>>
>>
>>--
>>PLEASE NOTE - As an anti-SPAM measure, e-mails will shortly
>>not be accepted by my machine from an unknown sender unless
>>the subject contains the phrase "Hi John".
>>
>>If you pass my e-mail address to others (which I am very happy
>>for you to do) please tell them to include this phrase in the
>>subject line of their first mailing to me.  Thanks.
>>
>>    Prof John Larmouth
>>    Larmouth T&PDS Ltd
>>    (Training and Protocol Development Services Ltd)
>>    1 Blueberry Road
>>    Bowdon                               j.larmouth@salford.ac.uk
>>    Cheshire WA14 3LS                    (put "Hi John" in subject)
>>    England
>>    Tel: +44 161 928 1605 Fax: +44 161 928 8069
>>
>>
> 
> 
> 
> 


-- 
PLEASE NOTE - As an anti-SPAM measure, e-mails will shortly
not be accepted by my machine from an unknown sender unless
the subject contains the phrase "Hi John".

If you pass my e-mail address to others (which I am very happy
for you to do) please tell them to include this phrase in the
subject line of their first mailing to me.  Thanks.

    Prof John Larmouth
    Larmouth T&PDS Ltd
    (Training and Protocol Development Services Ltd)
    1 Blueberry Road
    Bowdon                               j.larmouth@salford.ac.uk
    Cheshire WA14 3LS                    (put "Hi John" in subject)
    England			
    Tel: +44 161 928 1605		Fax: +44 161 928 8069