The correct answer is PGP. PGP stands for Pretty Good Privacy, an email encryption technology.

Input Controls are used to ensure that transactions are properly entered into the system once.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the
Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 218.

LOMAC is a security enhancement for Linux that uses Low Water-Mark Mandatory Access Control to protect the integrity of processes and data from viruses, Trojan horses, malicious remote users and compromised root daemons. LOMAC is implemented as a loadable kernel module - no kernel recompilations or changes to existing applications are required. Although not all the planned features are currently implemented, it presently provides sufficient protection to thwart script-kiddies, and is stable enough for everyday use.