Ray “The Diceman” Semko gives an operational security brief aboard Marine Corps Base Camp Lejeune, N.C., Oct. 4, 2010. Semko uses the acronym D.I.C.E., meaning defensive information to counter espionage to teach about the importance and practice of operational security. - Ray “The Diceman” Semko gives an operational security brief aboard Marine Corps Base Camp Lejeune, N.C., Oct. 4, 2010. Semko uses the acronym D.I.C.E., meaning defensive information to counter espionage to teach about the importance and practice of operational security.