1. An XML data encoding method comprising the steps of: converting into ASN.1 abstract syntax type a grammar definition for defining the grammar of XML data; separating said XML data into the contents text of a syntactic element and a structure an element name including the structure; converting said structure into an ASN.1 abstract syntax value that conforms to said ASN.1 abstract syntax type; converting said ASN.1 abstract syntax value into an ASN.1 transfer syntax; compressing said contents of said syntactic element; and combining the compressed contents of said syntactic element and said ASN.1 transfer syntax.