The secrecy of fraternity and sorority rituals have been studied through Greek history. The secret handshake is a ritual that gives the fraternity a way to symbolize their pact to belong together. When you are part of a fraternity, you are not supposed to ever tell anyone else how to do the secret handshake. More information is available at:
. http://campusactivities.suite101.com/article.cfm/sorority_rituals_and_initiation.