com.cladonia.security.signature.SignatureVerifier.java Source code

Introduction

Here is the source code for com.cladonia.security.signature.SignatureVerifier.java

Source

/*
 * $Id: SignatureVerifier.java,v 1.2 2004/04/06 08:30:48 knesbitt Exp $
 *
 * Copyright (C) 2002-2003, Cladonia Ltd. All rights reserved.
 *
 * This software is the proprietary information of Cladonia Ltd.  
 * Use is subject to license terms.
 */

package com.cladonia.security.signature;

import java.io.File;
import java.security.PublicKey;
import java.security.cert.X509Certificate;

import org.apache.xml.security.keys.KeyInfo;
import org.apache.xml.security.signature.XMLSignature;
import org.apache.xml.security.utils.Constants;
import org.apache.xml.security.utils.XMLUtils;
import org.apache.xpath.XPathAPI;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

import com.cladonia.xml.XngrURLUtilities;

/**
 * An implementation of an XML Signature verifier. 
 *
 * @version   $Revision: 1.2 $, $Date: 2004/04/06 08:30:48 $
 * @author Dogs bay
 */
public class SignatureVerifier {

    static {
        // apache api needs to be initialized before being used
        org.apache.xml.security.Init.init();
    }

    private Document doc = null;
    private String baseUri = null;

    /**
      * Constructs a SignaturVerifier using a dom and a base uri (can pass in the URL to the file
      * containg the signature instead)
      *
      * @param doc a dom containing the signature
      * @param baseUri the baseUri (this is required, I don't like it though), see the uri spec.
      */
    public SignatureVerifier(Document doc, String baseUri) {
        this.doc = doc;
        this.baseUri = baseUri;
    }

    /**
     * Verifys the signature.
     * Uses Xpath to find the signature in the dom. Uses the certificate from the KeyInfo section
     * to verify, if no certiicate is present then looks for the public key itself.
     * 
     * @return boolean true if the signature verifys, otherwise returns false
     */
    public boolean verify() throws SignatureException {
        try {

            // using xpath to locate the signature
            Element nscontext = XMLUtils.createDSctx(doc, "ds", Constants.SignatureSpecNS);
            Element sigElement = (Element) XPathAPI.selectSingleNode(doc, "//ds:Signature[1]", nscontext);

            // create the main apache object using the signature element and base uri
            XMLSignature signature = new XMLSignature(sigElement, baseUri);

            // look for the KeyInfo section
            KeyInfo ki = signature.getKeyInfo();
            if (ki != null) {
                X509Certificate cert = signature.getKeyInfo().getX509Certificate();
                if (cert != null) {
                    return signature.checkSignatureValue(cert);
                } else {
                    PublicKey publickey = signature.getKeyInfo().getPublicKey();
                    if (publickey != null) {
                        return signature.checkSignatureValue(publickey);
                    } else {
                        throw new Exception("Could not find the public key in the signature");
                    }
                }
            } else {
                throw new Exception("Could not find any KeyInfo in the signature");
            }

        } catch (Exception e) {
            // should log\trace error here
            final String errMsg = "The following error occurred verifying the signature: " + e.getMessage();
            throw new SignatureException(errMsg, e);
        }
    }

    // for testing purposes only
    public static void main(String[] args) throws Exception {
        org.apache.commons.logging.Log log = org.apache.commons.logging.LogFactory
                .getLog(SignatureGenerator.class.getName());

        log.info("**** Testing Signature Verification *****");

        javax.xml.parsers.DocumentBuilderFactory dbf = javax.xml.parsers.DocumentBuilderFactory.newInstance();
        dbf.setNamespaceAware(true);
        dbf.setAttribute("http://xml.org/sax/features/namespaces", Boolean.TRUE);

        File f = new File("c:\\temp\\sigout.xml");
        javax.xml.parsers.DocumentBuilder db = dbf.newDocumentBuilder();
        org.w3c.dom.Document doc = db.parse(new java.io.FileInputStream(f));

        SignatureVerifier verifier = new SignatureVerifier(doc, XngrURLUtilities.getURLFromFile(f).toString());
        if (verifier.verify())
            System.out.println("Signature 1 - verification passed");
        else
            System.out.println("Signature 1 - verification failed");

        File f2 = new File("c:\\temp\\sigout2.xml");
        org.w3c.dom.Document doc2 = db.parse(new java.io.FileInputStream(f2));

        // Note the apache api requires that you pass in a base uri, the location where the 
        // signature file is fine, if you do not know this (i.e in the case where the signature
        // file has not been saved), then just pass in "file:", as it works!!
        SignatureVerifier verifier2 = new SignatureVerifier(doc2, "file:");
        if (verifier2.verify())
            System.out.println("Signature 2 - verification passed");
        else
            System.out.println("Signature 2 - verification failed");

        File f3 = new File("c:\\temp\\vordelsig.xml");
        org.w3c.dom.Document doc3 = db.parse(new java.io.FileInputStream(f3));
        SignatureVerifier verifier3 = new SignatureVerifier(doc3, XngrURLUtilities.getURLFromFile(f3).toString());
        if (verifier3.verify())
            System.out.println("Vordel Signature - verification passed");
        else
            System.out.println("Vordel Signature - verification failed");

        File f4 = new File("c:\\temp\\license.xml");
        org.w3c.dom.Document doc4 = db.parse(new java.io.FileInputStream(f4));
        SignatureVerifier verifier4 = new SignatureVerifier(doc4, XngrURLUtilities.getURLFromFile(f4).toString());
        if (verifier4.verify())
            System.out.println("License Signature - verification passed");
        else
            System.out.println("License Signature - verification failed");

    }
}