W3C home > Mailing lists > Public > w3c-ietf-xmldsig@w3.org > October to December 2001

RE: New data format to substitute Canonical XML ?!?

From: Hallam-Baker, Phillip <pbaker@verisign.com>
Date: Wed, 17 Oct 2001 07:43:26 -0700
Message-ID: <2F3EC696EAEED311BB2D009027C3F4F405869802@vhqpostal.verisign.com>
To: "'Carl Ellison'" <cme@acm.org>, Christian Geuer-Pollmann <geuer-pollmann@nue.et-inf.uni-siegen.de>
Cc: w3c-ietf-xmldsig@w3.org
Given that virtually every XML document on earth only uses 64 distinct
symbols a 25% saving in space can be achieved using a cheesy FSR that could
be written in about 30 minutes.

The odd thing about the return of the Forces of ASN.1 is that reusing the
ASN.1 encoding format buys you precisely nothing if you are using the XML
data model. You can't use any existing ASN.1 tools and using any of the
toolkits would give you even more indigestion than usual.

In other venues the Forces of ASN.1 have claimed much higher compression -
from 200 bytes to 6. My response is that MD5 is guaranteed to compress *any*
bit stream of any length to 16 bytes and is only marginally harder to decode
than some of the more insane forms of ASN.1.


	Phill

Phillip Hallam-Baker FBCS C.Eng.
Principal Scientist
VeriSign Inc.
pbaker@verisign.com
781 245 6996 x227


> -----Original Message-----
> From: Carl Ellison [mailto:cme@acm.org]
> Sent: Wednesday, October 17, 2001 8:36 AM
> To: Christian Geuer-Pollmann
> Cc: w3c-ietf-xmldsig@w3.org
> Subject: Re: New data format to substitute Canonical XML ?!?
> 
> 
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> At 01:01 PM 10/17/2001 +0200, Christian Geuer-Pollmann wrote:
> >Hi all,
> >
> >just for your personal entertainment:
> >
> >http://www.eddf.org/
> >http://www.globera.com/eddf.php3
> >
> >Seems some people can't live without ASN.1 ;-))
> >
> >Christian
> >
> 
> Only 25% shorter than XML?
> 
> Canonical S-expressions [CSEXP] (as used in SPKI/SDSI) is also a
> binary format, is 1:1 with a major subset of XML (see
> http://world.std.com/~cme/html/spki.html#XML), and is about 50%
> shorter.  Then again, CSEXP is almost always shorter than traditional
> ASN.1 without any XML compatibility.
> 
> Of course, %-shorter is strictly a function of the ratio of tags to
> content and is a pretty meaningless measurement apart from a real
> document.
> 
>  - Carl
> 
> [P.S. for some reason, Netscape gets to the #XML tagged line above
> but IE doesn't.]
> 
> 
> -----BEGIN PGP SIGNATURE-----
> Version: PGP 6.5.8
> 
> iQA/AwUBO817KnPxfjyW5ytxEQINlgCfZapTJy1Gm4+btNQFkvBdj0Zh2S4AoIwV
> lndL3AxlCqs3rOR4sHcrcsop
> =Rgmh
> -----END PGP SIGNATURE-----
> 
> 
> +------------------------------------------------------------------+
> |Carl M. Ellison         cme@acm.org     http://world.std.com/~cme |
> |    PGP: 08FF BA05 599B 49D2  23C6 6FFD 36BA D342                 |
> +--Officer, officer, arrest that man. He's whistling a dirty song.-+
> 



Received on Wednesday, 17 October 2001 10:43:24 GMT

This archive was generated by hypermail 2.2.0 + w3c-0.29 : Thursday, 13 January 2005 12:10:14 GMT