168 Chapter 5 " XML Digital Signatures <xsl:template match="content/weather"> <xsl:apply-templates/> </xsl:template> <xsl:template match="location"> <xsl:apply-templates/> </xsl:template> <xsl:template match="time|wind|visibility|sky|note|dewpt|press |temperature|humidity"> </xsl:template> </xsl:stylesheet> </Transform> </Transforms> <DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/> <DigestValue>cMH2OCnUZui3DZtMnwl1QAlCtb8=</DigestValue> </Reference> </SignedInfo> <SignatureValue>lfLsdCZzOut1lOFJCDyYtKO/9CATXzt9ZgoImW7Nak7UOlGXi6KVB 1Z9nwu/sQ/7+QRNJxGUkwTBBIJblwXCjQ==</SignatureValue> </Signature> </Envelope> NOTE You can write your own code to perform XSL transformations on the server, or you can use the XSL ISAPI extension to automatically transform the XML page that includes a reference to the XSL style sheet. Some of the advantages to using the ISAPI filter are automatic selection and exe- cution of style sheets on the server, style sheet caching for improved per- formance, and the option to allow the pass-through of the XML for client-side processing. To learn more about the XSL ISAPI extension, visit http://msdn.microsoft.com/xml/general/xslisapifilter.asp. www.syngress.com Figure 5.15 Continued