Binary Data in XML

Jonathan A. Borden jborden at
Wed Sep 30 18:29:39 BST 1998

Yeah, but please include an


as a required attribute ... err or perhaps the default is 

another alternative to xml:packed might be
xml:content-encoding="base64" ??

Jonathan Borden
JABR Technology Corporation
mailto:jborden at

> Suppose I wrote up a NOTE, should occupy less than one page, proposing
> a reserved attribute xml:packed with, for the moment, only two
> allowed values, "none" and "base64".  The default value is "none".
> If an element has xml:packed="base64" this means that
> (a) the content of the element to which this is attached must be
>     pure #PCDATA, no child elements and no references, and
> (b) the content is encoded in base64, leading and trailing spaces allowed
> This obviously couldn't retroactively become part of XML 1.0, but
> if it went through a process and became a W3C recommendation, I bet
> every parser author in the world would support it in about 15 minutes.
> Base64 (a 4-for-3 encoding) wastes 33%, so I thought about perhaps
> inventing Base128 (8-for-7) or maybe even a higher level to cut down
> wasteage, but Base64 has the advantage that it avoids UTF8/ISO-8859 
> confusion and I bet Mr. LZW will eat that 33% anyhow...
> I also thought about xml:encoding=, but that conflicts with
> encoding= in the XML declaration in a confusing way.
> Are there any gotchas I'm missing?  Don't know if I could persuade
> one of the WGs to take it up, but it seems pretty obvious that there
> is not only industry demand but in fact people doing this already, so
> the case is pretty strong I think. -Tim

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