Re: [xcbf] SignedData Attributes - DigitalSignature Attributes

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

CXER does not support encoding instructions.  So an octet string value
in CXER can only be transferred using hex.

VXER - Variant XER - *will* provide a BASE64 transfer, but VXER is not
canonical.

(We have discussed providing a CVXER - Canonical Variant XER, but we
have almost agreed not to, at least at present, for some very good
reasons:  it is very difficult, and it will delay the progression of
VXER, which we know is needed.)

As Ed rightly says, there is no way you can have canonical encodings
that allow both hex and base64 for an OCTET STRING, even if you have a
"format=" attribute.  For canonical encodings, there is just one, and
only one, way of encoding an octet string.  For CXER, that is hex.

John L


Ed Day wrote:
> 
> I thought in a canonical XER encoding things could be done one way and only
> one way.  Doesn't introducing these attributes violate the canonical rules?
> 
> Regards,
> 
> Ed Day
> Principal Engineer
> Objective Systems, Inc.
> Tel: +1 (484) 875-3020
> Fax: +1 (484) 875-2913
> Toll-free: (877) 307-6855 (USA only)
> mailto:eday@obj-sys.com
> http://www.obj-sys.com
> 
> ----- Original Message -----
> From: "Phil Griffin" <phil.griffin@asn-1.com>
> To: "xcbf" <xcbf@lists.oasis-open.org>
> Sent: Monday, August 12, 2002 9:02 AM
> Subject: [xcbf] SignedData Attributes - DigitalSignature Attributes
> 
> > I proposed on 8/6 that the following XML markup be used
> > in XCBF.
> >
> >     <version> ........................ </version>
> >     <digestAlgorithms> ............... </digestAlgorithms>
> >     <encapContentInfo> ............... </encapContentInfo>
> >     <certificates format='base64'> ... </certificates>
> >     <crls format='base64'> ........... </crls>
> >     <signerInfos> .................... </signerInfos>
> >
> > The signature component of the SIGNATURE parameterized
> > type identifies a value of type BIT STRING. These bits
> > are not used as bit flags, and signatures tend to be in
> > the thousands of bits in length and can more easily and
> > compactly be represented as OCTET STRINGs. I propose that
> > the following XML markup be used for these values:
> >
> >     <signature format='hex'> ... </signature>
> >
> > So far, I have received no comments. Unless I hear comments
> > that use of these attributes is unacceptable, I will include
> > them in the next release of the XCBF document.
> >
> > Phil
> >
> >
> >
> >
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-- 
   Prof John Larmouth
   Larmouth T&PDS Ltd
   (Training and Protocol Development Services)
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