An applet, a Java program that runs in a browser, often has to access the
client resources. However, the security manager prevents an applet from
accessing client resources. To access client resources, the applet has to
have the proper permission. With this permission the applet can then access
the client system resources by way of the security manager. This phenomenon
is called stepping out of the sandbox. The sandbox is the security manager.
To achieve this phenomenon the applet needs to be signed and the client user
has to grant the applet permission. Signing the applet ensures that the
bytecode isn't tampered with, and the client user can be assured that the
contents of the applet are coming from a trusted source as stated by the
certificate.
Microsoft Internet Expl... (more)