in reply to binary data in XML
CDATA sections originate from a related SGML concept and are used for verbatim text (like code).
They are simply a way to stop any special entity-like processing and are certainly *not* meant for binary data. They are many schemes for binary XML.
If the document is valid UTF-8, then base64-enc of values is useful and does not need escaping as quotes are not part of the image set. Obviously you could also use directly the encoding data in a CDATA section but it seems less useful than:
The whole arsenal of MIME/PEM conversions can be used. But be careful, there is one pitfall: the scheme *breaks* if the xml document uses an (at least 2 bytes) encoding like UTF-16 as a base64 sequence of bytes is not valid UTF-16. The solution is to use an extra conversion like iconv -f ISO-88859-1 -t UTF-16 and its inverse.<data local_enc="base64"> <value>c3RlcGhhbgo=</value> </data>
Finally one way to encode ]]> would be to close the CDATA section after outputting ]] and then open another one starting with >cheers --stephan