Don't tell anyone about the handshake, apparently. That's a big no-no for this one sorority. 

Phi Sigma Sigma is taking a woman to court for talking about secret information concerning their sorority in an online forum. Lawyers seem to have a case stating it was a breach of contract when the woman signed the initiation agreement.

When you signed this contract you are bound to secrecy about things like the secret knock, the discreet and official handshake, and oaths they give at meetings.