T-functions revisited: New criteria for bijectivity/transitivity
  The paper presents new criteria for bijectivity/transitivity of T-functions and fast knapsack-like algorithm of evaluation of a T-function. Our approach is based on non-Archimedean ergodic theory: Both the criteria and algorithm use van der Put series to represent 1-Lipschitz $p$-adic functions and to study measure-preservation/ergodicity of these. 
Vladimir Anashin and Andrei Khrennikov and Ekaterina Yurova
cs.CR math.DS