Security models in mzscheme ?? [Was: Scheme interpreter with web interface?]

[John Casu <casuj@valinux.com>]

> 
> You will also find the _threads_ and _custodians_ built into PLT
> Scheme extremely useful for this task, to enforce timeouts and to
> gather up resources allocated by the user's program.
> 
> The security risks of doing this are massive.  Be sure you know what
> you're doing.

How would one go about adding a security model to mzscheme, so that you
could run your cgi/scheme code in a sandbox ?

Specifically, given a granted authority, I'd like to be able to create a 
new process, with a different capability or user/group id, to the parent.

I'm interested in building a scheme machine using the mzscheme/oskit
combo, and I'd like to make that a multiuser system.

thanks,

john c.