How to self-sign an applet?

Hello,

I have a graphics design applet which is not signed. With this applet the user can draw lines, circles etc. and may add regular images. There's a set of pre-made images, so the chances that the user will use his own are low.
However, there is an option for this, so if the user wants to insert his own images, an open dialog must show up and allow the user to select a file from his computer.

Unfortunately, to use an open dialog the applet must be signed, otherwise a security exception will be thrown. Because in most cases the user will not use his own images, it is stupid for me to sign the entire applet, and have the certificate window appear each time. The confirmation window should only appear when the user clicks on the Open button, in which case the applet should use the keystore which I'd provide and it should "sign itself", ie. certify itself with the browser's security manager.

How can I do this? I think the answer probably lies with the Keystore and Permission classes, but I haven't done this yet so I don't know.

If anyone can help please write!

Thanks, Csaba

Oh and before you suggest, I can't use Webstart because of client's request.

You are asking for a mechanism that fits the profile of a trojan or virus installer, so I doubt you'll solve this problem this way. Best just to sign the applet and forget about the user inconvenience. Browsers now ask to remember certs anyway.