One-stroke polynomials over a ring of modulo $2^w$
  Permutation polynomials over a ring of modulo $2^w$ are compatible with digital computers and digital signal processors, and so they are in particular expected to be useful for cryptography and pseudo random number generator. In general, the period of the polynomial should be long in such fields. In this paper, we derive the necessary and sufficient condition which specify one-stroke polynomials which are permutation polynomials whose periods are maximized. 
Atsushi Iwasaki, Ken Umeno
cs.IT math.IT