Accessing signed applets from netscape 4.5 browser


1)I need to write an applet in JDK 1.1 which will access serial port and printer. This applet will run on netscape 4.5 . Are signed applets necessary .. if yes how to do this .. any pointers .. sample code will be helpful.
I had tried example given by at, it throws security exception.
2) To run a signed applet on browser r there any software required on client side other than browser.
3)Are third party digital certificates must for this? (Our clients are known to us since the applet will be run within our organization.)
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"Unfortunately the Java Development Kit (JDK TM) 1.1 signing and verification is not supported by the web browsers (NetscapeTM's and Microsoft's.)"

You would need a java plug-in for what you need to do.

1) You need to explicitly define security policies for the applet sandbox, Security Manager
Here is an article and some reference at its end:

2) Besides JDK1.1 limitations on browsers, no software is required on the client side, except a compatible browser -- NN and IE supporting 40-bit encryption (don't know if better encryption is available yet).

3) For intranets, certificates from companies like Verisign are not necessary. You can make your own certificates by using the tools come with JDK -- javakey.exe, policytool.exe, keytool.exe, etc..

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Go for jdk1.2 , Java 2 plug-in.

check out the Java Tutirial on Security in java 1.2

some of tr resources r,
Code signing resources:

Creating Signed, Persistent Java Applets 



NN: Bypass the need for a certificate
Netscape provides a way to accept a codebase as trusted (then a certificate is not needed). This can be useful
during development or in a private Intranet. In the Netscape Users directory, there is a file called prefs.js. Adding
the line user_pref("signed.applets.codebase_principal_support", true);

will enable JAR file without a certificate to request privileges on your machine. If you agree, it will be possible for
an Applet to lauch a program, write a file on your hard disk or print on the printer. You will still have to ask for
privileges in your program using the Netscape capabilites classes.
Another way is to lower general security setting to more allow more freedom when running applets locally. Add or
modify the following entries in the prefs.js: user_pref("unsigned.applets.low_security_for_local_classes", true);
user_pref("signed.applets.local_classes_have_30_powers", true);
user_pref("signed.applets.low_security_for_local_classes", true);
user_pref("signed.applets.verbose_security_exception", true);

Then you don't need to asked for privileges for local classes.
When adding or modifying the file prefs.js, Netscape must not be running because your modification will be
overwritten. So shut down Netscape, edit the prefs.js and then restart Netscape.

(courtesy vladi21)

thanks for the inputs.
In IE 5.0, u can declare a site as a trusted site and give all the necessary permissions to that site. Is such a thing possible? This will eliminate the need of signing etc.


No. In NN it's not posible.
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