Every definitive movement has its own hand-sign. 9/11 Truth protesters should also have theirs. This video shows the Truth hand-sign which is similar to the OK hand-sign and resembles an inverted 911. The Truth 'masonic' handshake is simply an extension of the hand-sign to the handshake.

http://www.youtube.com/watch?v=YqU3pj1S-0w