Generating an XML Signature

<< genenveloped Example | Creating a Public Key Pair >>

GENENVELOPED

XAMPLE

227

The sample program will generate an enveloped signature of the document in the
file

envelope.xml

and store it in the file

envelopedSignature.xml

in the cur-

rent working directory.

Generating an XML Signature

This example shows you how to generate an XML Signature using the XML
Digital Signature API. More specifically, the example generates an enveloped
XML Signature of an XML document. An enveloped signature is a signature that
is contained inside the content that it is signing. The example uses DOM (the
Document Object Model) to parse the XML document to be signed and a JSR
105 DOM implementation to generate the resulting signature.

A basic knowledge of XML Signatures and their different components is helpful
for understanding this section. See

http://www.w3.org/TR/xmldsig-core/

for

more information.

Instantiating the Document to be Signed

First, we use a JAXP

DocumentBuilderFactory

to parse the XML document

that we want to sign. An application obtains the default implementation for

Doc-

umentBuilderFactory

by calling the following line of code:

DocumentBuilderFactory dbf =

DocumentBuilderFactory.newInstance();

We must also make the factory namespace-aware:

dbf.setNamespaceAware(true);

Next, we use the factory to get an instance of a

DocumentBuilder

, which is used

to parse the document:

DocumentBuilder builder = dbf.newDocumentBuilder();
Document doc = builder.parse(new FileInputStream(argv[0]));