Task: Question Understanding
Input (English): Context : Twofish was designed by Bruce Schneier, John Kelsey, Doug Whiting, David Wagner, Chris Hall, and Niels Ferguson; the ``extended Twofish team'' who met to perform further cryptanalysis of Twofish and other AES contest entrants included Stefan Lucks, Tadayoshi Kohno, and Mike Stay. 
Question : Which is the basis of Twofish?
Output (English): based on