申論 2電子媒體封裝檔格式，部分的Document Type Definition（DTD）如下，請詳述每一列的意義：（40 分）列號 DTD 內容 意義<?xml version="1.0"encoding="cns11643"?>2 <!ELEMENT 媒體封裝檔 (Signature)><!ELEMENT Signature (SignedInfo,3 SignatureValue, KeyInfo?,Object*)><!ATTLIST Signature Id ID#IMPLIED><!ELEMENT SignedInfo5 (CanonicalizationMethod,SignatureMethod, Reference+)><!ELEMENT CanonicalizationMethod(#PCDATA)* ><!ATTLIST CanonicalizationMethodAlgorithm CDATA #REQUIRED ><!ELEMENT Transform (#PCDATA|XPath)*>