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Asked: 2026-06-09T10:28:05+00:00

I am developing an Application that will perform Encryption/Decryption at client side only. I

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I am developing an Application that will perform Encryption/Decryption at client side only. I am using Spring, jdk 1.6+, and eclipse. I have developed an Applet that contain cryptographic code it looks like :

public void accessToken(){
        try{
            File tmpConfigFile = File.createTempFile("pkcs11", "conf");
            tmpConfigFile.deleteOnExit();
            PrintWriter configWriter = new PrintWriter(new FileOutputStream(tmpConfigFile), true);
            configWriter.println("name=eToken");
            configWriter.println("library=" + "C:\\WINDOWS\\system32\\eTPKCS11.dll");
            configWriter.println("slotListIndex=0");
            configWriter.println("showInfo=true");

            this.pkcs11Provider = new SunPKCS11(tmpConfigFile.getAbsolutePath());
            Security.addProvider(this.pkcs11Provider);

            CallbackHandler cbh = new DialogCallbackHandler();
            KeyStore.Builder ksBuilder = KeyStore.Builder.newInstance("PKCS11", null, new KeyStore.CallbackHandlerProtection(cbh));                     
            KeyStore ks = ksBuilder.getKeyStore();
            ks.load(null, null);            
        }catch(Exception e){
            e.printStackTrace();
        }
    }

I have created jar file and signed it, it works well when I run it as “run on Java Applet” on local machine from eclipse also it works well and prompts for password on page load when I open html page which includes this applet but when I click on checkbox that calls this accessToken() applet method it gives error on java console like:

java.lang.SecurityException: Unable to create temporary file
    at java.io.File.checkAndCreate(Unknown Source)
    at java.io.File.createTempFile(Unknown Source)
    at java.io.File.createTempFile(Unknown Source)
    at message.MessageApplet.accessToken(MessageApplet.java:49)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at sun.plugin.javascript.JSInvoke.invoke(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at sun.plugin.javascript.JSClassLoader.invoke(Unknown Source)
    at sun.plugin2.liveconnect.JavaClass$MethodInfo.invoke(Unknown Source)
    at sun.plugin2.liveconnect.JavaClass$MemberBundle.invoke(Unknown Source)
    at sun.plugin2.liveconnect.JavaClass.invoke0(Unknown Source)
    at sun.plugin2.liveconnect.JavaClass.invoke(Unknown Source)
    at sun.plugin2.main.client.LiveConnectSupport$PerAppletInfo$DefaultInvocationDelegate.invoke(Unknown Source)
    at sun.plugin2.main.client.LiveConnectSupport$PerAppletInfo$3.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.plugin2.main.client.LiveConnectSupport$PerAppletInfo.doObjectOp(Unknown Source)
    at sun.plugin2.main.client.LiveConnectSupport$PerAppletInfo$LiveConnectWorker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)

and my html page looks like:

<SCRIPT LANGUAGE="JavaScript">
            function selectedCity() 
            {
                var elem = document.getElementById('cityRb');

                if(elem.checked)
                {
                    document.messageApplet.accessToken();
                }      
            }
        </SCRIPT></HEAD>
    <BODY >
        <b>This is the Applet</b>
     <script src="http://www.java.com/js/deployJava.js"></script>
    <script>
        <!-- applet id can be used to get a reference to the applet object -->
        var attributes = { id:'messageApplet', code:'message.MessageApplet',  width:1, height:1} ;
        var parameters = {jnlp_href: 'message-applet.jnlp'} ;
        deployJava.runApplet(attributes, parameters, '1.6');
    </script>

    <FORM NAME="CityChoice">
        <input type="radio" id="cityRb" name="City" value="Boston" onClick="selectedCity()"> Boston<br>
    </form>
</BODY >

and my JNLP file looks like:

<jnlp spec="1.0+" codebase="" href="">
    <information>
        <title>Message Applet</title>
        <vendor>Fountainhead</vendor>
    <offline-allowed/>
    </information>
<update check="background"/>
    <security>
    <all-permissions/>
    </security>
    <resources>
        <!-- Application Resources -->
    <j2se version="1.6+"
              href="http://java.sun.com/products/autodl/j2se"/>
        <jar href="message.jar" main="true" />

    </resources>
    <applet-desc 
         name="Message Applet"
         main-class="message.MessageApplet"
         width="300"
         height="300">
     </applet-desc>
     <update check="background"/>
</jnlp>

all files and jar are in same directory and my applet class is in message folder
please help me I am stuck here…

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1 Answer

  1. Editorial Team

    This happened because you are calling your applet’s method from your javascript. Actually when you call any signed applet’s method from javascript it behaves as unsigned, because both having own security sand box and you have to perform in that specific sandbox. Now I have made changes in your code as below.

    final File myFile = (File) AccessController.doPrivileged(new PrivilegedAction() {
                public Object run(){
                    String fileName = System.getProperty("user.home") +
                      System.getProperty("file.separator") +
                      "pkcs11.conf";                    
                    return new File(fileName);
                }});

    this AccessController allow you to create a file on client machine. I am not good in English hence if there any mistakes then sorry.

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