Note that the root user can read every file, and the contents of memory if she/he desires, so this person must be trusted

This is really getting off of the subject of Perl, but as knowledge is paramount in securing any system, I'm posting it anyway.

One should note also that there have been recent developments of security systems which -- even in their default configurations -- deny even root access to system objects. Such things are sometimes known as Mandatory Access Controls. If security is an issue (and I cannot imagine a situation where it is not), then the administrator should investigate these avenues to be implemented in tandem with existing methodologies.