KeyValue中定义的XML KeyValue元素的表示 。 
        KeyValue对象包含可用于验证签名的单个公钥。 
        XML模式定义定义为: 
          <element name="KeyValue" type="ds:KeyValueType"/>
    <complexType name="KeyValueType" mixed="true">
      <choice>
        <element ref="ds:DSAKeyValue"/>
        <element ref="ds:RSAKeyValue"/>
        <any namespace="##other" processContents="lax"/>
      </choice>
    </complexType>
    <element name="DSAKeyValue" type="ds:DSAKeyValueType"/>
    <complexType name="DSAKeyValueType">
      <sequence>
        <sequence minOccurs="0">
          <element name="P" type="ds:CryptoBinary"/>
          <element name="Q" type="ds:CryptoBinary"/>
        </sequence>
        <element name="G" type="ds:CryptoBinary" minOccurs="0"/>
        <element name="Y" type="ds:CryptoBinary"/>
        <element name="J" type="ds:CryptoBinary" minOccurs="0"/>
        <sequence minOccurs="0">
          <element name="Seed" type="ds:CryptoBinary"/>
          <element name="PgenCounter" type="ds:CryptoBinary"/>
        </sequence>
      </sequence>
    </complexType>
    <element name="RSAKeyValue" type="ds:RSAKeyValueType"/>
    <complexType name="RSAKeyValueType">
      <sequence>
        <element name="Modulus" type="ds:CryptoBinary"/>
        <element name="Exponent" type="ds:CryptoBinary"/>
      </sequence>
    </complexType>  
        可以通过调用KeyInfoFactory类的newKeyValue方法并向其传递表示公钥值的PublicKey来创建KeyValue实例。 
        以下是从存储在KeyStore中的Certificate的DSAPublicKey创建KeyValue的示例 : 
          KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
 PublicKey dsaPublicKey = keyStore.getCertificate("myDSASigningCert").getPublicKey();
 KeyInfoFactory factory = KeyInfoFactory.getInstance("DOM");
 KeyValue keyValue = factory.newKeyValue(dsaPublicKey);  
        该类将DSAKeyValue和RSAKeyValue元素分别作为类型DSAPublicKey和RSAPublicKey的对象返回。 
        请注意,并非架构中的所有字段都可以作为这些类型的参数进行访问。