Plugin has mechanism to dynamically install extensions for applet.
However, for this mechanism to work, the extension has to have at least some VERSION information and also provide installer if more sophiscated installation is needed. Currently, JCE is distributed with JDK. However, due to import restriction imposed by different countries, only the weak-crypto version of JCE is included in JDK. For applets which require strong crypto, plugin need to download strong crypto JCE at runtime.
In order for plugin to retrieve strong crypto JCE, JCE needs to provide its own installer for this purpose as well as provide version info for Plugin.