Hope this helps!
import java.io.*;
import
javax.xml.parsers.*;
import java.security.*;
import org.w3c.dom.*;
import
org.apache.xml.security.signature.*;
import
org.apache.xml.security.transforms.*;
import
org.apache.xml.security.Init;
import
org.bouncycastle.util.encoders.Base64;
/**
* This code
generates an IRMark (secure hash value) for an input document.
* The
value is a base64 encoded SHA1 digest of a signature
* transform
over a certain style of document.
*
* The code has a
number of jar dependencies:-
* xmlsec.jar - The Apache XML
Security Library
* log4j-1.2.5.jar - The Apache Log
utility
* xalan.jar - Apache XSLT/XPath
processor
* xercesImpl.jar - Apache XML
processor
* bc-jce-jdk13-114.jar - Bouncy Castle JCE
library
*
* The Bouncy Castle JCE provider is
automatically downloaded
* by the Apache XML sec library
build so you may already have
* that.
*/
public
class IRMark {
/**
* Generate and print the
IRmark.
*
* @param args - Pass
the filename of the input document
* @throws
Exception
*/
public static void main(String
args[]) throws Exception {
// Init
the Apache XML security library
Init.init();
// Check we are given
a file to work with
if (args.length!=1)
{
System.out.println("Use: IRmark <file>
");
return;
}
// Open the input
file
FileInputStream fis=null;
try
{
fis=new FileInputStream(args[0]);
}
catch (FileNotFoundException e)
{
System.out.println("The file " + args[0] + " could
not be opened.");
return;
}
// Load file into a
byte array
byte[] data=""> try
{
int
bytes=fis.available();
data=""
byte[bytes];
fis.read(data);
} catch
(IOException e) {
System.out.println("Error reading
file.");
e.printStackTrace();
}
// First part is to
run the a transform over the input to extract the
//
fragment to be digested. This is done by setting up a
Transforms
// object from a Template and then executing
against the input document
// The transforms to
be performed are specified by using the template XML
below.
String transformStr
=
"<?xml
version='1.0'?>\n"
+
"<dsig:Transforms xmlns:dsig='http://www.w3.org/2000/09/xmldsig#'
xmlns:gt='http://www.govtalk.gov.uk/CM/envelope'
xmlns:ir='http://www.govtalk.gov.uk/taxation/SA'>\n"
+ "<dsig:Transform
Algorithm='http://www.w3.org/TR/1999/REC-xpath-19991116'>\n"
+ "<dsig:XPath>\n"
+
"count(ancestor-or-self::node()|/gt:GovTalkMessage/gt:Body)=count(ancestor-or-self::node())\n"
+
" and count(self::ir:IRmark)=0 \n"
+ " and
count(../self::ir:IRmark)=0 \n"
+
"</dsig:XPath>\n"
+
"</dsig:Transform>\n"
+
"<dsig:Transform
Algorithm='http://www.w3.org/TR/2001/REC-xml-c14n-20010315#WithComments'/>\n"
+ "</dsig:Transforms>\n"
;
// Parse the
transform details to create a
document
DocumentBuilderFactory
dbf=DocumentBuilderFactory.newInstance();
dbf.setNamespaceAware(true);
DocumentBuilder
db=dbf.newDocumentBuilder();
Document doc=db.parse(new
ByteArrayInputStream(transformStr.getBytes()));
// Construct a Apache
security Transforms object from that document
Transforms
transforms = new Transforms(doc.getDocumentElement(), null);
// Now perform the
transform on the input to get the
results.
XMLSignatureInput input =
new XMLSignatureInput(data);
XMLSignatureInput result =
transforms.performTransforms(input);
// Uncomment this line to see transform
output
// System.out.println(new
String(result.getBytes()));
// Second part is to run output via SHA1
digest
// This is done via the
standard java.security API
MessageDigest md =
MessageDigest.getInstance("SHA");
md.update(result.getBytes());
byte[]
digest=md.digest();
// And finally print
a Base64 of the digest with
// The help of the BouncyCastle
JCE library
System.out.println("IRmark: " + new
String(Base64.encode(digest)));
}
}
